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general description the max9756/MAX9757/max9758 combine dual, 2.3w, bridge tied load (btl) stereo audio power amplifiers and a directdrive tm headphone amplifier in a single device. these devices feature single-supply voltage operation, shutdown mode, logic-selectable gain, a headphone sense input, a 31-step analog volume control, and indus- try-leading click-and-pop suppression. the headphone amplifier uses maxim? patent-pending directdrive archi- tecture that produces a ground-referenced output from a single supply, eliminating the need for large dc-blocking capacitors. the max9756/MAX9757 feature automatic level control (alc) that automatically limits output power to the speak- er in the event of an overpowered output. the max9756/max9758s?150ma internal linear regula- tor provides a complete solution for dac- or codec- based designs. the max9756/MAX9757/max9758 are offered in space- saving, thermally efficient 32-pin (5mm x 5mm x 0.8mm) and 36-pin thin qfn (6mm x 6mm x 0.8mm) packages. all devices are specified over the extended -40? to +85? temperature range. features ? automatic level control?rotects speakers ? analog volume control ? 120mw directdrive headphone amplifiers (16 ) ? 150ma adjustable ldo ? class ab, 2.3w, stereo btl speaker amplifiers (3 ) ? high 95db psrr ? low-power shutdown mode ? industry-leading click-and-pop suppression ? short-circuit and thermal protection ? beep input max9756/MAX9757/max9758 2.3w stereo speaker amplifiers and directdrive headphone amplifiers with automatic level control ________________________________________________________________ maxim integrated products 1 vol alc single supply 4.5v to 5.5v single supply 4.5v to 5.5v single supply 4.5v to 5.5v 1.2v to 5v hps beep max9756 ldo alc vol alc hps beep MAX9757 alc vol 1.2v to 5v hps beep max9758 ldo simplified block diagrams ordering information applications part alc ldo pin-package max9756 etx+ ? 36 thin qfn-ep** MAX9757 etj+* 32 thin qfn-ep** max9758 etj+* 32 thin qfn-ep** 19-3782; rev 0; 8/05 for pricing, delivery, and ordering information, please contact maxim/dallas direct! at 1-888-629-4642, or visit maxim? website at www.maxim-ic.com. evaluation kit available notebook pcs tablet pcs portable dvd players flat-panel tvs pc displays lcd projectors portable audio note: all devices specified for -40? to +85? operating temperature range. + denotes lead-free package. * future product?ontact factory for availability. ** ep = exposed paddle.
max9756/MAX9757/max9758 2.3w stereo speaker amplifiers and directdrive headphone amplifiers with automatic level control 2 _______________________________________________________________________________________ absolute maximum ratings electrical characteristics (v dd = pv dd = hpv dd = cpv dd = in = +5.0v, gnd = pgnd = cpgnd = 0, shdn = v dd , regen = v dd , dr = set = gnd, c bias = 1?, c pvss = 1?, c1 = c2 = 1?, pref = unconnected, speaker loads terminated between out_+ and out_-, headphone load terminated between hp_ and gnd, gain1 = gain2 = gain3 = vol = 0 (a v(sp) = 15db, a v(hp) = 0db), t a = -40? to +85?, unless otherwise noted. typical values are at t a = +25?.) (note 1) stresses beyond those listed under ?bsolute maximum ratings?may cause permanent damage to the device. these are stress rating s only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specificatio ns is not implied. exposure to absolute maximum rating conditions for extended periods may affect device reliability. supply voltage (v dd , pv dd , hpv dd , cpv dd , in to gnd) ....+6v pgnd, cpgnd to gnd ......................................................?.3v cpv ss , c1n, v ss to gnd......................................-6.0v to +0.3v hp_ to gnd ...........................................................................?v any other pin .............................................-0.3v to (v dd + 0.3v) duration of out_ short circuit to gnd or pv dd ........continuous duration of out_+ short circuit to out_- .................continuous duration of hp_ short circuit to gnd, v ss , or hpv dd .........................................................continuous duration of out short circuit to gnd........................continuous continuous current (pv dd , out_, pgnd) ...........................1.7a continuous current (cpv dd , c1n, cpgnd, c1p, cpv ss , v ss , hpv dd , hp_, in, out) .............................................0.85a continuous input current (all other pins) .........................?0ma continuous power dissipation (t a = +70?, single-layer board) 32-pin thin qfn (derate 18.6mw/? above +70?).....1490mw 36-pin thin qfn (derate 20.4mw/? above +70?).....1633mw continuous power dissipation (t a =+70?, multilayer board) 32-pin thin qfn (derate 24.9mw/? above +70?).....1990mw 36-pin thin qfn (derate 27.7mw/? above +70?).....2180mw junction temperature .....................................................+150? operating temperature range ...........................-40? to +85? storage temperature range .............................-65? to +150? lead temperature (soldering, 10s) .................................+300? parameter symbol conditions min typ max units general supply voltage range v dd , pv dd inferred from psrr test 4.5 5.5 v headphone supply voltage hpv dd inferred from psrr test 3.0 5.5 v hps = gnd, speaker mode, r l = 14 29 quiescent supply current i dd i dd = i vdd + i hpvdd + i cpvdd hps = 5v, headphone mode, r l = 713 ma shutdown supply current i shdn shdn = regen = gnd 0.2 5 a bias voltage v bias 2.2 2.43 2.65 v switching time t sw gain or input switching 10 ? input resistance r in inl and inr 10 20 30 k turn-on time t son 25 ms speaker amplifiers (hps = gnd) output offset voltage v os measured between out_+ and out_-, t a = +25? ?.4 ?5 mv pv dd = 4.5v to 5.5v, t a = +25? 75 95 f = 1khz, v ripple = 200mv p-p 83 power-supply rejection ratio (note 2) psrr f = 10khz, v ripple = 200mv p-p 68 db r l = 8 0.9 1.3 r l = 4 2.0 output power (note 3) p out thd+n = 1%, f = 1khz (t a = +25?) r l = 3 2.3 w r l = 8 , btl p out = 1w, f = 1khz 0.009 total harmonic distortion plus noise thd+n r l = 4 , btl p out = 1w, f = 1khz 0.015 % r l = 8 , btl p out = 1w, bw = 22hz to 22khz, unweighted 92 signal-to-noise ratio snr r l = 8 , btl p out = 1w, a weighted 95 db
max9756/MAX9757/max9758 2.3w stereo speaker amplifiers and directdrive headphone amplifiers with automatic level control _______________________________________________________________________________________ 3 electrical characteristics (continued) (v dd = pv dd = hpv dd = cpv dd = in = +5.0v, gnd = pgnd = cpgnd = 0, shdn = v dd , regen = v dd , dr = set = gnd, c bias = 1?, c pvss = 1?, c1 = c2 = 1?, pref = unconnected, speaker loads terminated between out_+ and out_-, headphone load terminated between hp_ and gnd, gain1 = gain2 = gain3 = vol = 0 (a v(sp) = 15db, a v(hp) = 0db), t a = -40? to +85?, unless otherwise noted. typical values are at t a = +25?.) (note 1) parameter symbol conditions min typ max units noise v n bw = 22hz to 22khz, unweighted, measured at output, input at ac gnd 71 ? rms capacitive-load drive c l no sustained oscillations 200 pf crosstalk l to r, r to l, f = 10khz 80 db slew rate sr measured between out_+ and out_- 1.3 v/? gain3 = 0 gain2 = 0 gain1 = 0 15 gain3 = 0 gain2 = 0 gain1 = 1 16.5 gain3 = 0 gain2 = 1 gain1 = 0 18 gain3 = 0 gain2 = 1 gain1 = 1 19.5 gain3 = 1 gain2 = 0 gain1 = 0 21 gain3 = 1 gain2 = 0 gain1 = 1 22.5 gain3 = 1 gain2 = 1 gain1 = 0 24.0 gain (maximum volume settings) (note 4) a vmax (spkr) gain3 = 1 gain2 = 1 gain1 = 1 25.5 db into shutdown 65 click-and-pop level k cp peak voltage, 32 samples/second, a weighted (note 5) out of shutdown 38.5 dbv headphone amplifiers (hps = v dd ) output offset voltage v os ( hp ) t a = +25? 2 7 mv hpv dd = 3v to 5.5v, t a = +25? 70 90 f = 1khz, v ripple = 200mv p-p 72 power-supply rejection ratio (note 2) psrr f = 10khz, v ripple = 200mv p-p 70 db r l = 32 40 68 output power (note 3) p out thd+n = 1%, f = 1khz (t a = +25?) r l = 16 = , v out = 1v rms , f = 1khz 0.02 total harmonic distortion plus noise thd+n r l = 16 , v out = 1v rms , f = 1khz 0.04 % r l = 32 , btl p out = 65mw, bw = 22hz to 22khz, unweighted 97 signal-to-noise ratio snr r l = 32 , btl p out = 65w, bw = 22hz to 22khz, a weighted 100 db noise v n bw = 22hz to 22khz 20.4 ? rms capacitive-load drive c l no sustained oscillations 200 pf crosstalk l to r, r to l, f = 10khz 60 db slew rate sr 1.4 v/? gain2 = 0, hps = 1 0 gain (maximum volume settings) (note 6) a vmax ( hp ) gain2 = 1, hps = 1 3.0 db into shutdown 62 click-and-pop level k cp peak voltage, 32 samples/second, a weighted (note 4) out of shutdown 50 dbv
max9756/MAX9757/max9758 2.3w stereo speaker amplifiers and directdrive headphone amplifiers with automatic level control 4 _______________________________________________________________________________________ electrical characteristics (continued) (v dd = pv dd = hpv dd = cpv dd = in = +5.0v, gnd = pgnd = cpgnd = 0, shdn = v dd , regen = v dd , dr = set = gnd, c bias = 1?, c pvss = 1?, c1 = c2 = 1?, pref = unconnected, speaker loads terminated between out_+ and out_-, headphone load terminated between hp_ and gnd, gain1 = gain2 = gain3 = vol = 0 (a v(sp) = 15db, a v(hp) = 0db), t a = -40? to +85?, unless otherwise noted. typical values are at t a = +25?.) (note 1) parameter symbol conditions min typ max units charge pump charge-pump frequency f osc 500 550 600 khz volume control vol input impedance r vol 100 m vol input hysteresis 10 mv full mute voltage (note 7) 0.858 x hpv dd v full mute attenuation f in = 1khz -85 db input impedance r vol_ any gain setting 100 m a v = +15db to 0db ?.2 a v = -2db to -20db ?.3 channel matching a v = -22db to -56db ?.0 db beep input beep signal amplitude threshold t a = +25?, r b = 47k (see beep input section) 0.3 v beep signal frequency threshold t a = +25? 300 hz automatic level control speaker amplifier (max9756/MAX9757) pref threshold accuracy r pref = 180k 5 8.1 % maximum gain compression 6.0 6.3 db attack time c t = 1? (note 8) 15 ms hold time time between attack and release phases 50 ms 0v < v dr < (0.3v x v dd )30 0.4v < v dr < (0.6v x v dd ) 9.5 release time (note 9) c t = 1?, release from 6db 0.8v < v dr < v dd 3 s dr input (tri-state input) dr input voltage high v drh 0.8 x v dd v dd v dr input voltage middle v drm 0.4 x v dd 0.6 x v dd v dr input voltage low v drl 0 0.3 x v dd v input leakage current 0v v dr v dd ? ? logic inputs (gain_, shdn , regen) input high voltage v ih 2v input low voltage v il 0.8 v input leakage current i in ? ?
max9756/MAX9757/max9758 2.3w stereo speaker amplifiers and directdrive headphone amplifiers with automatic level control _______________________________________________________________________________________ 5 note 1: all devices are 100% production tested at room temperature. all temperature limits are guaranteed by design. note 2: psrr is specified with the amplifier input connected to gnd through r in and c in . note 3: output power levels are measured with the tqfn? exposed paddle soldered to the ground plane. note 4: speaker path gain is defined as: a vspkr = (v out+ - v out- )/v in__ ). note 5: speaker mode testing performed with 8 resistive load connected across btl output. headphone mode testing per- formed with 32 resistive load connected between hp_ and gnd. mode transitions are controlled by shdn . note 6: headphone path gain is defined as: a vhp = v hp_ /v in__ . note 7: see table 3 for detains on the mute levels. note 8: attack envelope is exponential. attack time is defined as the 15 x 10 3 x c t . note 9: time for the gain to return to within 10% of nominal gain setting after the input signal has fallen below the pref threshold. release is linear in db. release time is proportional to magnitude of gain compression. note 10: dropout voltage is defined as (v in - v out ) when v out is 2% below the value of v out for v in = v out(nom) + 1v. electrical characteristics (continued) (v dd = pv dd = hpv dd = cpv dd = in = +5.0v, gnd = pgnd = cpgnd = 0, shdn = v dd , regen = v dd , dr = set = gnd, c bias = 1?, c pvss = 1?, c1 = c2 = 1?, pref = unconnected, speaker loads terminated between out_+ and out_-, headphone load terminated between hp_ and gnd, gain1 = gain2 = gain3 = vol = 0 (a v(sp) = 15db, a v(hp) = 0db), t a = -40? to +85?, unless otherwise noted. typical values are at t a = +25?.) (note 1) parameter symbol conditions min typ max units logic input headphone (hps) input high voltage v ih 2v input low voltage v il 0.8 v hps pullup current 35 ? low-dropout linear regulator input voltage range v in inferred from line regulation 3.5 5.5 v i out = 0ma, shdn = gnd 100 160 supply (ground) current i q i out = 150ma 350 ? shutdown current i shdn regen = 0v 0.1 3 a output current i out 150 ma fixed output voltage accuracy i out = 1ma ?.5 % adjustable output voltage range v set 4.85 v set reference voltage v set 1.19 1.21 1.23 v set dual-mode threshold 200 mv set input leakage current i set ?0 ?00 na i out = 50ma 25 50 dropout voltage (note 10) v od v out = 4.65v (fixed output operation) i out = 150ma 100 150 mv output current limit i lim 300 ma startup time 20 ? line regulation v in = 3.5v to 5.5v, v out = 2.5v, i out = 1ma -0.1 +0.01 +0.1 %/v load regulation v out = 4.65v, 1ma < i out < 150ma 0.5 % f = 1khz 60 ripple rejection v ripple = 200mv p-p f = 10khz 50 db output voltage noise 20hz to 22khz, c out = 2 x 1?, i out = 150ma, v out = 4.65v 100 ? rms
max9756/MAX9757/max9758 2.3w stereo speaker amplifiers and directdrive headphone amplifiers with automatic level control 6 _______________________________________________________________________________________ typical operating characteristics (v dd = pv dd = hpv dd = cpv dd = in = +5.0v, gnd = pgnd = cpgnd = 0v, shdn = v dd , regen = dr = set = gnd, c bias = 1?, c pvss = 1?, c1 = c2 = 1?, pref = unconnected, gain1 = 1, gain2 = gain3 = vol = 0v, measurement bw = 22hz to 22khz, t a = +25?, unless otherwise noted.) total harmonic distortion plus noise vs. frequency (headphone mode) max9756 toc01 frequency (hz) thd+n (%) 10k 1k 100 0.01 0.1 1 10 0.001 10 100k v dd = 5v r l = 3 output power = 500mw output power = 1.8w total harmonic distortion plus noise vs. frequency (headphone mode) max9756 toc02 frequency (hz) thd+n (%) 10k 1k 100 0.01 0.1 1 10 0.001 10 100k v dd = 5v r l = 4 output power = 500mw output power = 1.5w total harmonic distortion plus noise vs. frequency (headphone mode) max9756 toc03 frequency (hz) thd+n (%) 10k 1k 100 0.01 0.1 1 10 0.001 10 100k v dd = 5v r l = 8 output power = 500mw output power = 1w total harmonic distortion plus noise vs. output power (speaker mode) max9756 toc04 output power (w) thd+n (%) 3.0 2.5 2.0 1.5 1.0 0.5 0.01 0.1 1 10 100 0.001 03.5 v dd = 5v r l = 3 f in = 100hz f in = 1khz f in = 10khz total harmonic distortion plus noise vs. output power (speaker mode) max9756 toc05 output power (w) thd+n (%) 3.0 2.5 2.0 1.5 1.0 0.5 0.01 0.1 1 10 100 0.001 0 3.5 v dd = 5v r l = 4 f in = 100hz f in = 1khz f in = 10khz total harmonic distortion plus noise vs. output power (speaker mode) max9756 toc06 output power (w) thd+n (%) 1.5 1.0 0.5 0.01 0.1 1 10 100 0.001 0 2.0 v dd = 5v r l = 8 f in = 100hz f in = 1khz f in = 10khz output power vs. load resistance (speaker mode) max9756 toc07 load resistance ( ) output power (w) 10 0.5 1.0 1.5 2.0 2.5 3.0 0 1100 v dd = 5v f = 1khz thd+n = 10% thd+n = 1% power dissipation vs. output power (speaker mode) max9756 toc08 output power (w) power dissipation (w) 3.5 3.0 2.5 2.0 1.5 1.0 0.5 0.5 1.0 1.5 2.0 2.5 3.0 0 0 4.0 f = 1khz p out = p outl + p outr r l = 8 r l = 4 power-supply rejection ratio vs. frequency (speaker mode) max9756 toc09 frequency (hz) psrr (db) 10k 1k 100 -110 -100 -90 -80 -70 -60 -50 -40 -30 -20 -10 0 -120 10 100k v ripple = 200mv p-p r l = 8
max9756/MAX9757/max9758 2.3w stereo speaker amplifiers and directdrive headphone amplifiers with automatic level control _______________________________________________________________________________________ 7 crosstalk vs. frequency (speaker mode) max9756 toc10 frequency (hz) crosstalk (db) 10k 1k 100 -100 -90 -80 -70 -60 -50 -40 -30 -20 -10 0 -110 10 100k left to right right to left v in = 200mv p-p turn-on response (speaker mode) max9756 toc11 10ms/div shdn 5v/div out_+ 2v/div out_- 2v/div out_+ - out_- 50mv/div turn-off response (speaker mode) max9756 toc12 10ms/div shdn 5v/div out_+ 2v/div out_- 2v/div out_+ - out_- 50mv/div total harmonic distortion plus noise vs. frequency (headphone mode) max9756 toc13 frequency (hz) thd+n (%) 10k 1k 100 0.01 0.1 1 10 0.001 10 100k v dd = 5v r l = 16 output power = 100mw output power = 40mw total harmonic distortion plus noise vs. frequency (headphone mode) max9756 toc14 frequency (hz) thd+n (%) 10k 1k 100 0.01 0.1 1 10 0.001 10 100k v dd = 5v r l = 32 output power = 20mw output power = 60mw total harmonic distortion plus noise vs. frequency (headphone mode) max9756 toc15 frequency (hz) thd+n (%) 10k 1k 100 0.01 0.1 1 10 0.001 10 100k v dd = 3.3v r l = 16 output power = 80mw output power = 20mw total harmonic distortion plus noise vs. frequency (headphone mode) max9756 toc16 frequency (hz) thd+n (%) 10k 1k 100 0.01 0.1 1 10 0.001 10 100k v dd = 3.3v r l = 32 output power = 50mw output power = 20mw total harmonic distortion plus noise vs. output power (headphone mode) max9756 toc17 output power (mw) thd+n (%) 180 160 140 120 100 80 60 40 20 0.01 0.1 1 10 100 0.001 0200 hpv dd = 5v r l = 16 f in = 100hz f in = 10khz f in = 1khz total harmonic distortion plus noise vs. output power (headphone mode) max9756 toc18 output power (mw) thd+n (%) 90 80 70 60 50 40 30 20 10 0.01 0.1 1 10 100 0.001 0100 hpv dd = 5v r l = 32 f in = 100hz f in = 10khz f in = 1khz typical operating characteristics (continued) (v dd = pv dd = hpv dd = cpv dd = in = +5.0v, gnd = pgnd = cpgnd = 0v, shdn = v dd , regen = dr = set = gnd, c bias = 1?, c pvss = 1?, c1 = c2 = 1?, pref = unconnected, gain1 = 1, gain2 = gain3 = vol = 0v, measurement bw = 22hz to 22khz, t a = +25?, unless otherwise noted.)
max9756/MAX9757/max9758 2.3w stereo speaker amplifiers and directdrive headphone amplifiers with automatic level control 8 _______________________________________________________________________________________ typical operating characteristics (continued) (v dd = pv dd = hpv dd = cpv dd = in = +5.0v, gnd = pgnd = cpgnd = 0v, shdn = v dd , regen = dr = set = gnd, c bias = 1?, c pvss = 1?, c1 = c2 = 1?, pref = unconnected, gain1 = 1, gain2 = gain3 = vol = 0v, measurement bw = 22hz to 22khz, t a = +25?, unless otherwise noted.) total harmonic distortion plus noise vs. output power (headphone mode) max9756 toc19 output power (mw) thd+n (%) 100 80 60 40 20 0.01 0.1 1 10 100 0.001 0120 hpv dd = 3.3v r l = 16 f in = 100hz f in = 10khz f in = 1khz total harmonic distortion plus noise vs. output power (headphone mode) max9756 toc20 output power (mw) thd+n (%) 80 90 70 40 50 60 30 10 20 0.01 0.1 1 10 100 0.001 0 100 hpv dd = 3.3v r l = 32 f in = 100hz f in = 1khz f in = 10khz output power vs. load resistance (headphone mode) max9756 toc21 load resistance ( ) output power (mw) 100 20 40 60 80 100 120 140 0 10 1000 hpv dd = 3.3v f = 1khz thd+n = 10% thd+n = 1% output power vs. load resistance (headphone mode) max9756 toc22 load resistance ( ) output power (mw) 100 20 40 60 80 100 120 140 160 180 200 0 10 1000 hpv dd = 5v f = 1khz thd+n = 10% thd+n = 1% power dissipation vs. output power (headphone mode) max9756 toc23 output power (mw) power dissipation (mw) 225 200 175 150 125 100 75 50 25 0.2 0.4 0.6 0.8 0 0 250 f = 1khz p out = p hl + p hr r l = 16 r l = 32 output power vs. supply voltage (headphone mode) max9756 toc24 supply voltage (v) output power (mw) 5.0 4.5 4.0 3.5 10 20 30 40 50 60 70 80 90 100 110 120 130 140 0 3.0 5.5 r l = 16 r l = 32 thd+n = 1% power-supply rejection ratio vs. frequency (headphone mode) max9756 toc25 frequency (hz) psrr (db) 10k 1k 100 -90 -80 -70 -60 -50 -40 -30 -20 -10 0 -100 10 100k v ripple = 100mv p-p inputs ac-grounded hpv dd = 5v hpv dd = 3.3v crosstalk vs. frequency (headphone mode) max9756 toc26 frequency (hz) crosstalk (db) 10 1 0.1 -100 -90 -80 -70 -60 -50 -40 -30 -20 -10 0 -110 0.01 100 r l = 32 f = 1khz v in = 200mv p-p right to left left to right output power vs. charge-pump capacitance (headphone mode) max9756 toc27 load ( ) output power (mw) 30 25 20 15 35 40 45 40 30 50 60 70 80 90 100 120 110 130 140 150 20 10 50 c1 = c2 = 1 f c1 = c2 = 2.2 f f = 1khz thd+n = 1%
max9756/MAX9757/max9758 2.3w stereo speaker amplifiers and directdrive headphone amplifiers with automatic level control _______________________________________________________________________________________ 9 turn-on response (headphone mode) max9756 toc28 10ms/div shdn 5v/div hpr 10mv/div hpl 10mv/div turn-off response (headphone mode) max9756 toc29 10ms/div shdn 5v/div hpr 10mv/div hpl 10mv/div supply current vs. supply voltage max9756 toc30 supply voltage (v) supply current (ma) 5.3 5.1 4.9 4.7 8 11 14 17 20 5 4.5 5.5 hps = gnd hps = v dd shutdown current vs. supply voltage max9756 toc31 supply voltage (v) shutdown current (na) 5.3 5.1 4.7 4.9 100 200 300 400 500 600 0 4.5 5.5 power limiting of sine burst (fast attack and fast release) max9756 toc32 10ms/div output 2v/div ct 1v/div power limiting of sine burst (fast attack and slow release) max9756 toc33 40ms/div output 2v/div ct 1v/div power limiting of sine burst (slow attack and slow release) max9756 toc33 2s/div output 2v/div ct 1v/div ldo output voltage accuracy vs. load current max9756 toc35 load current (ma) deviation (%) 125 100 25 50 75 -1.5 -1.0 -0.5 0 0.5 1.0 1.5 2.0 -2.0 0150 typical operating characteristics (continued) (v dd = pv dd = hpv dd = cpv dd = in = +5.0v, gnd = pgnd = cpgnd = 0v, shdn = v dd , regen = dr = set = gnd, c bias = 1?, c pvss = 1?, c1 = c2 = 1?, pref = unconnected, gain1 = 1, gain2 = gain3 = vol = 0v, measurement bw = 22hz to 22khz, t a = +25?, unless otherwise noted.)
max9756/MAX9757/max9758 2.3w stereo speaker amplifiers and directdrive headphone amplifiers with automatic level control 10 ______________________________________________________________________________________ typical operating characteristics (continued) (v dd = pv dd = hpv dd = cpv dd = in = +5.0v, gnd = pgnd = cpgnd = 0v, shdn = v dd , regen = dr = set = gnd, c bias = 1?, c pvss = 1?, c1 = c2 = 1?, pref = unconnected, gain1 = 1, gain2 = gain3 = vol = 0v, measurement bw = 22hz to 22khz, t a = +25?, unless otherwise noted.) ldo output voltage accuracy vs. temperature max7956 toc37 temperature ( c) deviation (%) 60 35 10 -15 -4 -3 -2 -1 0 1 2 3 4 5 -5 -40 85 dropout voltage vs. load current max9756 toc38 load current (ma) dropout voltage (v) 125 100 75 50 25 -200 -100 0 100 200 300 -300 0150 power-supply rejection ratio vs. frequency (ldo) max9756 toc39 frequency (hz) psrr (db) 10k 1k 100 -90 -80 -70 -60 -50 -40 -30 -20 -10 0 -100 10 100k v ripple = 100mv p-p ldo output noise max9756 toc40 200 s/div ldo_out 1mv/div crosstalk vs. frequency (ldo) max9756 toc36 frequency (hz) crosstalk (db) 10 1 0.1 -100 -90 -80 -70 -60 -50 -40 -30 -20 -10 0 -110 0.01 100 r l = 4 p out(spk) = 1w i out = 90ma i out = 10ma i out = 50ma
max9756/MAX9757/max9758 2.3w stereo speaker amplifiers and directdrive headphone amplifiers with automatic level control ______________________________________________________________________________________ 11 typical operating characteristics (continued) (v dd = pv dd = hpv dd = cpv dd = in = +5.0v, gnd = pgnd = cpgnd = 0v, shdn = v dd , regen = dr = set = gnd, c bias = 1?, c pvss = 1?, c1 = c2 = 1?, pref = unconnected, gain1 = 1, gain2 = gain3 = vol = 0v, measurement bw = 22hz to 22khz, t a = +25?, unless otherwise noted.) output noise vs. frequency (ldo) max9756 toc41 frequency (hz) noise ( v) 10k 1k 100 20 30 40 50 60 70 80 90 100 110 10 10 100k c out = 2 f 10hz to 100khz line-transient response max9756 toc42 40 s/div v in 500mv/div 4.5v 5.5v ldo_out 20mv/div load-transient response max9756 toc43 20 s/div 50v 0v i load 25mv/div ldo_out = 4.65v 20mv/div ldo shutdown response max9756 toc44 100ms/div regen 5v/div ldo_out 1v/div pin description pin max9756 MAX9757 max9758 name function 1 32 32 inl left-channel audio input 21 1 gain1 gain control input 1 32 2 gain2 gain control input 2 43 3 gain3 gain control input 3 54 4 beep audible alert beep input 6, 22 5, 21 5, 21 pgnd power ground 76 6 outl+ left-channel positive speaker output 87 7 outl- left-channel negative speaker output 9,19 8,18 8, 18 pv dd speaker amplifier power supply. bypass with 1? ceramic capacitor to pgnd.
max9756/MAX9757/max9758 2.3w stereo speaker amplifiers and directdrive headphone amplifiers with automatic level control 12 ______________________________________________________________________________________ pin description (continued) pin max9756 MAX9757 max9758 name function 10 9 9 cpv dd charge-pump power supply. bypass with 1? ceramic capacitor to cpgnd. 11 10 10 c1p charge-pump flying-capacitor positive terminal. connect a 1? capacitor from c1p to c1n. 12 11 11 cpgnd charge-pump ground 13 12 12 c1n charge-pump flying-capacitor negative terminal. connect a 1? capacitor from c1p to c1n. 14 13 13 cpv ss charge-pump negative output. connect to v ss . 15 14 14 v ss headphone amplifier negative power supply. bypass with 1? ceramic capacitor to gnd. 16 15 15 hpr right headphone output 17 16 16 hpl left headphone output 18 17 17 hpv dd headphone positive power supply. bypass with 1? ceramic capacitor to gnd. 20 19 19 outr- right-channel negative speaker output 21 20 20 outr+ right-channel positive speaker output 23 22 22 hps h ead p hone s ense inp ut. leave h p s unconnected i f autom ati c head p hone sensi ng i s not used . 24 23 regen ld o e nab l e. c onnect re ge n to v d d to enab l e the ld o. c onnect to g n d to d i sab l e ld o. 25 23 dr automatic level control attack to release time ratio select. hardwired to v dd , gnd, or bias to set the attack to release ratio; see the alc section. 26 24 24 bias common-mode bias voltage. bypass with a 1.0? capacitor to gnd. 27 25 25 shdn shutdown input. drive shdn low to disable the audio amplifiers. connect shdn to v dd for normal operation. 28 26 26 vol analog volume control input 29 27 pref p ow er - li m i ti ng inp ut. c onnect a r esi stor fr om p re f to g n d to set the sp eaker outp ut cl am p i ng l evel . leave p re f unconnected to d i sab l e alc ; see the alc secti on. 30 27 set regulator feedback input. connect to gnd for 4.65v fixed output. connect to resistor-divider for adjustable output; see the low-dropout linear regulator section. 31 28 28 gnd ground 32 29 v dd power supply 33 in ldo input. bypass with two 1? ceramic capacitors to gnd. 34 30 out ldo output. bypass with two 1? ceramic capacitors to gnd. 35 30 ct automatic level control attack and release timing capacitor. connect ct to gnd to disable alc; see the alc section. 36 31 31 inr right-channel audio input 29 v dd power-supply and ldo input. bypass with two 1? ceramic capacitors to gnd. ep ep ep ep exposed pad. the external pad lowers the package? thermal impedance by providing a direct-heat conduction path from the die to the pc board. connect the exposed thermal pad to gnd.
max9756/MAX9757/max9758 2.3w stereo speaker amplifiers and directdrive headphone amplifiers with automatic level control ______________________________________________________________________________________ 13 detailed description the max9756/MAX9757/max9758 combine dual, 2w btl stereo audio power amplifiers with a directdrive headphone amplifier in a single device. the stereo power amplifiers deliver up to 2.3w per channel into a 3 speaker from a 5v supply and the stereo head- phone amplifiers deliver up to 130mw per channel into a 16 headphone from a 5v supply. the max9756/MAX9757 feature alc that automatically controls output power to the speaker, preventing loud- speaker, overload and provides optimized dynamic range. the max9756/MAX9757/max9758 feature 31-step ana- log volume control and a beep input. the amplifier gain is pin programmable. these devices feature click- and-pop suppression, eliminating the need for discrete muting circuitry. speaker and headphone outputs have short-circuit and thermal protection. the max9756/max9758s?internal ldo features maxim? dual mode feedback. the ldo output volt- age is either fixed at 4.65v (set = gnd), or adjusted between 1.23v and 5v using a resistive divider at set. the ldo delivers up to 150ma of continuous current, and can be enabled independently from the audio amplifiers. short-circuit and thermal-overload protec- tion are provided for the ldo. all devices feature a single-supply voltage, a shut- down mode, logic-selectable gain, and a headphone sense input. industry-leading click-and-pop suppres- sion eliminates audible transients during power and shutdown cycles. each signal path consists of an input amplifier that sets the signal-path gain and feeds both the speaker and headphone amplifiers (figure 1). the speaker amplifier uses a btl architecture, doubling the voltage drive to the speakers and eliminating the need for dc-blocking capacitors. the output consists of two signals, identical in magnitude, but 180 out of phase. the headphone amplifiers use maxim? patented directdrive architecture that eliminates the bulky output dc-blocking capacitors required by traditional head- phone amplifiers. a charge pump inverts the positive supply (cpv dd ), creating a negative supply (cpv ss ). the headphone amplifiers operate from these bipolar supplies with their outputs biased about gnd (figure 2). the amplifiers have almost twice the supply range compared to other single-supply amplifiers, nearly qua- drupling the available output power. the benefit of the gnd bias is that the amplifier outputs do not have a dc component (typically v dd /2). this eliminates the large dc-blocking capacitors required with conventional headphone amplifiers, conserving board space and system cost while improving frequency response. out_+ out_- volume control bias in_ vol bias bias hp_ gnd alc figure 1. max9756/MAX9757 signal path +v dd -v dd gnd conventional driver-biasing scheme directdrive biasing scheme v dd /2 v dd gnd v out figure 2. traditional headphone amplifier output waveform vs. directdrive headphone amplifier output waveform dual mode is a trademark of maxim integrated products, inc.
max9756/MAX9757/max9758 the max9756/MAX9757/max9758 feature an under- voltage lockout that prevents operation from an insuffi- cient power supply and click-and-pop suppression that eliminates audible transients on startup and shutdown. the amplifiers include thermal-overload and short-cir- cuit protection. an additional feature of the amplifiers is that there is no phase inversion from input to output. automatic level control (alc) two-watt amplifiers are commonly used in notebook pcs (almost always powered from a 5v supply). with an 8 speaker driven from a btl amplifier, the maxi- mum theoretical continuous power available is: see figure 5 for suggested alc component values. the alc feature offers two benefits: 1) to limit amplifier power to protect a loudspeaker. 2) to make input signals with a wide dynamic range more intelligible by boosting low-level signals with- out distorting the high-level signals. a device without alc experiences clipping at the output when too much gain is applied to the input. alc pre- vents clipping at the output when too much gain is applied to the input, eliminating output clipping. figure 3 shows a comparison of an overgained speaker input with and without alc. the max9756/max9758 control the gain to the speakers by first detecting that the output voltage to the speaker has exceeded a preset limit. the speaker amplifier gain is rapidly reduced to correct for the excessive output power. this process is known as the attack time. when the signal subsequently lowers in amplitude, the gain is held at the reduced state for a short period before slowly increasing to the normal value. this process is known as the hold and release time. the speed at which the ampli- fiers adjust to changing input signals is set by the exter- nal timing capacitor c ct and the setting of logic input dr. the output power limit can be set by adjusting the value of the external resistor connected to pref. gain reduction is a function of input signal amplitude with a maximum alc attenuation of 6db. figure 4 shows the effect of an input burst exceeding the preset limit, output attack, hold and release times. this process (referred to as ?imiting?in audio) limits the amplifier output power so loudspeaker overload can be prevented. if the attack and release times are configured to respond too fast, audible artifacts often, described as ?umping?or ?reathing,?can occur as the gain is rapid- ly adjusted to follow the dynamics of the signal. for best results, adjust the time constant of the alc to accommo- date the source material. notebook applications in which music cds and dvds are the main audio source, a 495? attack time with a 990ms release time is recom- mended with a 1.2w output into an 8 load. p v r w out peak speaker . = ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? = ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? = 2 5 2 8 156 22 2.3w stereo speaker amplifiers and directdrive headphone amplifiers with automatic level control 14 ______________________________________________________________________________________ alc disable, clipping at the output input signal 10ms/div 10ms/div output signal alc enable, no clipping at the output figure 3. alc disabled vs. alc enabled
attack time the attack time is the time it takes to reduce the gain after the input signal has exceeded the threshold level. suggested attack time range is from 150? to 50ms. the gain attenuation in attack is exponential and the attack time is defined as one time constant. the time constant of the attack is given by 15,000 x c ct sec- onds (where c ct is the external timing capacitor). use a short attack time for the alc to react quickly to transient signals, such as snare drum beats (music) or gun shots (dvd). fast attack times can lead to gain ?umping?where rapid alc action can be heard reacting to dynamic material. use a longer attack time to allow the alc to ignore short-duration peaks and only reduce the gain when a noticeable increase in loudness occurs. short-dura- tion peaks are not reduced, but louder passages are. this allows the louder passages to be reduced in vol- ume, thereby maximizing output dynamic range. having the attack time too long can possibly result in some damage to the loudspeaker under harsh condi- tions. hold time hold time is the delay after the signal falls below the threshold level before the release phase is initiated. hold time is internally set to 50ms and nonadjustable. the hold time is cancelled by any signal exceeding the set threshold level and attack is reinitiated. release time the release time is how long it takes for the gain to return to its normal level after the input signal has fallen below the threshold level and 50ms hold time has expired. release time is defined as release from a 6db gain compression to 10% of the nominal gain setting after the input signal has fallen below pref threshold and the 50ms hold time has expired. release time is adjustable between 95ms and 10s. the release time is set by picking an attack time using c ct and setting the attack to release time ratio by configuring dr as shown in table 2. release time is linear in db with time and is inversely proportional to the magnitude of gain com- pression: use a small ratio to maximize the speed of the alc. use a large ratio to maximize the sound quality and prevent repeated excursions above the threshold from being independently adjusted by the alc. release and attack times are set by selecting the capacitance value between ct and gnd, and by set- ting the logic state of dr (table 1). dr is a tristate logic input that sets the attack-to-release time ratio. a fixed hold time of 50ms is internally added to the release time. max9756/MAX9757/max9758 2.3w stereo speaker amplifiers and directdrive headphone amplifiers with automatic level control ______________________________________________________________________________________ 15 output 2v/div ct 1v/div 10ms/div figure 4. attack, hold, and release time table 1. attack and release time attack time release time timing capacitor (c ct ) dr = ? dr = v dd dr = v bias dr = gnd 10nf 150? 30ms 95ms 300ms 33nf 495? 99ms 313ms 990ms 100nf 1.5ms 300ms 950ms 3s 330nf 4.95ms 990ms 3.1s 9.9s 1? 15ms 3s 9.5s 2.2? 33ms 6.6s 3.3? 49.5ms 10s
max9756/MAX9757/max9758 the release/attack time ratio that can be achieved by programming dr is listed in table 2. output power threshold to set the threshold at which speaker output is clamped, an external resistor must be connected from pref to ground. the suggested external resistor range is from 100k to 200k (for best results use a 1% resis- tor). leaving pref unconnected disables the alc function. a constant current of 12? is sourced at pref, so that a 180k resistor results in 1.2w clamp limit on an 8 load and a 200k resistor results in a 1.5w clamp limit on an 8 load (figure 6). use the following equation to choose the value for r pref for the desired maximum output power level based on a sine wave input: gain selection the max9756/MAX9757/max9758 feature an internally set, selectable gain. the gain1, gain2, and gain3 inputs set the maximum gain for the speaker and head- phone amplifiers (table 3). the gain of the device can vary based upon the voltage at vol but does not exceed the maximum gain listed below (see the analog volume (vol) control section). rk pr pref out l = ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? 180 1 166 8 . 2.3w stereo speaker amplifiers and directdrive headphone amplifiers with automatic level control 16 ______________________________________________________________________________________ max9756 MAX9757 33nf 180k values shown for an output power threshold of 1.2w with an r l = 8 attack time of 495 s and a release time of 990ms dr 5v v dd ct pref figure 5. recommended output power threshold, attack, and release time components output power threshold vs. r pref r pref (k ) output power threshold (w) 190 180 170 160 150 140 130 120 110 0.5 1.0 1.5 2.0 2.5 3.0 0 100 200 r l = 4 r l = 8 figure 6. output power threshold vs. r pref table 2. release to attack ratio dr release/attack ratio v dd 200 v bias 633 gnd 2000 table 3. maximum gain settings gain3 gain2 gain1 speaker mode gain (db) headphone mode gain (db) 0 0 0 +15 0 0 0 1 +16.5 0 0 1 0 +18 +3 0 1 1 +19.5 +3 1 0 0 +21 0 1 0 1 +22.5 0 1 1 0 +24 +3 1 1 1 +25.5 +3
analog volume control (vol) the max9756/MAX9757/max9758 feature an analog volume control that varies the gain of the device in 31 discrete steps based upon the dc voltage applied to vol (see table 4). the input range of vol is from 0 (full volume) to hpv dd (full mute), with example step sizes shown in table 3. connect the reference of the device driving vol (figure 7) to hpv dd . connect vol to gnd (full volume) if volume control is not used. max9756/MAX9757/max9758 2.3w stereo speaker amplifiers and directdrive headphone amplifiers with automatic level control ______________________________________________________________________________________ 17 table 4. volume levels v vol (v) = multiplier x hpv dd speaker mode gain (db) headphone mode gain (db) m u l tiplie r v vol ( min ) * v vol ( max ) * ga i n 3 = 0 ga i n 2 = 0 ga i n 1 = 0 ga i n 3 = 0 ga i n 2 = 0 ga i n 1 = 1 ga i n 3 = 0 ga i n 2 = 1 ga i n 1 = 0 ga i n 3 = 0 ga i n 2 = 1 ga i n 1 = 1 ga i n 3 = 1 ga i n 2 = 0 ga i n 1 = 0 ga i n 3 = 1 ga i n 2 = 0 ga i n 1 = 1 ga i n 3 = 1 ga i n 2 = 1 ga i n 1 = 0 ga i n 3 = 1 ga i n 2 = 1 ga i n 1 = 1 ga i n 3 = x ga i n 2 = 0 ga i n 1 = x ga i n 3 = x ga i n 2 = 1 ga i n 1 = x 0.07 0.00 0.49 15 16.5 18 19.5 21 22.5 24 25.5 0 3 0.16 0.49 0.57 14 16 17.5 19 20 22 23.5 25 -1 2.5 0.18 0.57 0.64 13 15 17 18.5 19 21 23 24.5 -2 2 0.21 0.64 0.72 12 14 16.5 18 18 20 22.5 24 -3 1.5 0.23 0.72 0.80 10 13 16 17.5 16 19 22 23.5 -5 1 0.25 0.80 0.88 81215 1714182123-70 0.28 0.88 0.95 6 10 14 16.5 12 16 20 22.5 -9 -1 0.30 0.95 1.03 4 8 13 16 10 14 19 22 -11 -2 0.32 1.03 1.11 2 6 12 15 8 12 18 21 -13 -3 0.35 1.11 1.19 0 4 10 14 6 10 16 20 -15 -5 0.37 1.19 1.26 -2 2 8 13 4 8 14 19 -17 -7 0.39 1.26 1.34 -4 0 6 12 2 6 12 18 -19 -9 0.42 1.34 1.42 -6 -2 4 10 0 4 10 16 -21 -11 0.44 1.42 1.50 -8 -4 2 8 -2 2 8 14 -23 -13 0.46 1.50 1.57 -10 -6 0 6 -4 0 6 12 -25 -15 0.49 1.57 1.65 -12 -8 -2 4 -6 -2 4 10 -27 -17 0.51 1.65 1.73 -14 -10 -4 2 -8 -4 2 8 -29 -19 0.54 1.73 1.80 -16 -12 -6 0 -10 -6 0 6 -31 -21 0.56 1.80 1.88 -18 -14 -8 -2 -12 -8 -2 4 -33 -23 0.58 1.88 1.96 -20 -16 -10 -4 -14 -10 -4 2 -35 -25 0.61 1.96 2.04 -22 -18 -12 -6 -16 -12 -6 0 -37 -27 0.63 2.04 2.11 -24 -20 -14 -8 -18 -14 -8 -2 -39 -29 0.65 2.11 2.19 -26 -22 -16 -10 -20 -16 -10 -4 -41 -31 0.68 2.19 2.27 -28 -24 -18 -12 -22 -18 -12 -6 -43 -33 0.70 2.27 2.35 -32 -26 -20 -14 -26 -20 -14 -8 -47 -35 0.72 2.35 2.42 -36 -28 -22 -16 -30 -22 -16 -10 -51 -37 0.75 2.42 2.50 -40 -32 -24 -18 -34 -26 -18 -12 -55 -39 0.77 2.50 2.58 -44 -36 -26 -20 -38 -30 -20 -14 -59 -41 0.79 2.58 2.66 -48 -40 -28 -22 -42 -34 -22 -15 -63 -43 0.82 2.66 2.73 -52 -44 -32 -24 -46 -38 -26 -18 -67 -47 0.84 2.73 2.81 -56 -48 -36 -26 -50 -42 -30 -20 -71 -51 0.93 2.81 3.30 mute mute mute mute mute mute mute mute mute mute max9756 v ref dac hpv dd vol figure 7. volume control circuit *based on hpv dd = 3.3v. x = don? care.
max9756/MAX9757/max9758 since the volume control (vol) adc is ratiometric to hpv dd , any variations in hpv dd are negated. the gain step sizes are not constant; the step sizes are 0.5db/step at the upper extreme, 2db/step in the midrange, and 4db/step at the lower extreme. figure 8 shows the transfer function of the volume control for a 3.3v supply. low-dropout linear regulator the max9756/max9758s?low-dropout linear regulator (ldo) can be used to provide a clean power supply to a codec or other circuitry. the ldo can be enabled independently of the audio amplifiers. regen enables/disables the ldo, set regen = v dd to enable the ldo or set regen = gnd to disable. the ldo is capable of providing up to 150ma continuous current and features maxim? dual mode feedback. when set is connected to gnd, the output is internally set to approximately 4.65v. adjust the output from 1.23v to 5v by connecting two external resistors, used as a volt- age-divider, at set (figure 9). the output voltage is set by the following equation: where v set = 1.23v. to simplify resistor selection: since the input bias current at set is nominally zero, large resistance values can be used for r1 and r2 to minimize power consumption without losing accuracy. up to 1.5m is acceptable for r2. to minimize the current consumption, it is desirable to use high-value resistors (> 10k for the external feed- back divider (r1, r2). the input capacitance at set and the stray and wiring capacitance should be com- pensated by placing a small capacitor (in the 10pf range) across the upper feedback resistor r1 (see figure 9). this capacitor creates a zero in the feedback loop to reduce overshoot. overcompensation can cause poor stability in the high current range. the regulator should be compensated with two 1f ceramic capacitors connected between in and gnd and out and gnd. x7r dielectric with 10% tolerance is recommended. the esr of each capacitor should not exceed 40m for good stability up to the full-rated current (150ma). place the capacitors as close as possible to the device to limit the parasitic resistance and inductance. there is no upper limit to the amount of additional bypass capacitance. directdrive headphone amplifier unlike the max9756/MAX9757/max9758, conventional single-supply headphone amplifiers typically have their outputs biased at half the supply voltage for maximum dynamic range. large coupling capacitors are needed to block this dc bias from the headphones. without these capacitors, a significant amount of dc current flows to the headphone, resulting in unnecessary power dissipation and possible damage to both head- phone and headphone amplifier. rr v v out set 12 1 = ? ? ? ? ? ? ? vv r r out set =+ ? ? ? ? ? ? 1 1 2 2.3w stereo speaker amplifiers and directdrive headphone amplifiers with automatic level control 18 ______________________________________________________________________________________ figure 8. volume control transfer function volume control transfer function v vol (v) gain (db) 3.5 3.0 2.5 2.0 1.5 1.0 0.5 -60 -40 -20 0 20 40 -80 0 4.0 gain1 = gain2 = gain3 = 1 hpv dd = 3.3v speaker mode headphone mode figure 9. adjustable output using external feedback resistors max9756 max9758 out set gnd 1 f 1 f 10pf r1 r2
maxim? patent-pending directdrive architecture uses a charge pump to create an internal negative supply volt- age. this allows the max9756/MAX9757/max9758 head- phone amplifier output to be biased at gnd, almost doubling the dynamic range while operating from a single supply. with no dc component, there is no need for the large dc-blocking capacitors. instead of two large capacitors (220?, typ), the max9756/MAX9757/ max9758 charge pump requires only two small ceramic capacitors (1? typ), conserving board space, reducing cost, and improving the frequency response of the headphone amplifier. see the output power vs. charge- pump capacitance graph in the typical operating characteristics for details of the possible capacitor values. low-frequency response in addition to the cost and size disadvantages, the dc- blocking capacitors limit the low-frequency response of the amplifier. the impedance of the headphone load to the dc-blocking capacitor forms a highpass filter with the -3db point determined by: where r l is the impedance of the headphone and c out is the value of the dc-blocking capacitor. the highpass filter is required by conventional single- ended, single-supply headphone amplifiers to block the midrail dc component of the audio signal from the headphones. depending on the -3db point, the filter can attenuate low-frequency signals within the audio band. larger values of c out reduce the attenuation but are physically larger, more expensive capacitors. figure 10 shows the relationship between the size of c out and the resulting low-frequency attenuation. note that the -3db point for a 16 headphone with a 100?-blocking capacitor is 100hz, well within the audio band. charge pump the max9756/MAX9757/max9758 feature a low-noise inverting charge pump to generate the negative rail necessary for directdrive headphone operation. the switching frequency is well beyond the audio range, and does not interfere with the audio signals. the switch drivers feature a controlled switching speed that minimizes noise generated by turn-on and turn-off tran- sients. limiting the switching speed of the charge pump minimizes the di/dt noise caused by the parasitic bond wire and trace inductance. headphone sense input (hps) the headphone sense input (hps) monitors the head- phone jack and automatically configures the max9756/ MAX9757/max9758 based upon the voltage applied at hps. a voltage of less than 0.8v enables the speaker amplifier. a voltage of greater than 2v disables the speaker amplifiers and enables the headphone ampli- fiers. for automatic headphone detection, connect hps to the control pin of a 3-wire headphone jack as shown in figure 11. with no headphone present, the output impedance of the headphone amplifier pulls hps low. when a headphone plug is inserted into the jack, the control pin is disconnected from the tip contact and hps is pulled to v dd with 35?. fdb rc l out ?= 3 1 2 max9756/MAX9757/max9758 2.3w stereo speaker amplifiers and directdrive headphone amplifiers with automatic level control ______________________________________________________________________________________ 19 0 -15.0 10 100 1k 10k 100k low-frequency rolloff (r l = 16 ) -12.0 -13.5 -6.0 -7.5 -9.0 -10.5 -3.0 -4.5 -1.5 frequency (hz) attenuation (db) directdrive 330 f 220 f 100 f 33 f figure 10. low-frequency attenuation of common dc- blocking capacitor values max9756/ MAX9757/ max9758 14k 35 a 14k v dd hps hpl hpr shutdown control figure 11. hps configuration
max9756/MAX9757/max9758 bias the max9756/MAX9757/max9758 feature an internally generated, power-supply independent, common-mode bias voltage of 2.5v referenced to gnd. bias provides both click-and-pop suppression and sets the dc bias level for the amplifiers. choose the value of the bypass capacitor as described in the bias capacitor section. no external load should be applied to bias. any load lowers the bias voltage, affecting the overall perfor- mance of the device. beep input the max9756/MAX9757/max9758 feature an audible alert beep input (beep) that accepts a mono system alert signal and mixes it into the stereo audio path. when the amplitude of v beep exceeds 300mv p-p and the frequency of the beep signal is greater than 300hz, the beep signal is mixed into the active audio path (speaker or headphone). if the signal at v beep is either < 300mv p-p or < 300hz, the beep signal is not mixed into the audio path. the amplitude of the beep signal at the device output is roughly the amplitude v beep times the gain of the selected signal path. the input resistor (r b ) sets the gain of the beep input amplifier, and thus the amplitude of v beep . choose r b based on: the total beep gain is given by: where 47k is the value of the beep amplifier feedback resistor, v beep is the beep amplifier output, v in(beep) is the beep input amplitude, and v out(beep) is the total beep output signal. a v(beepout ) is given by the values listed in table 5. note that v beep must be higher than 300mv p-p . the beep amplifier can be set up as either an attenuator, if the original alert signal amplitude is too large, or to gain up the alert signal if it is below 300mv p-p . ac-couple the alert signal to beep. choose the value of the coupling capacitor as described in the input filtering section. multiple beep inputs can be summed (figure 12). v v k r a out beep in beep b v beepout () () () =+ ? ? ? ? ? ? 47 r vk v b in beep beep () 47 2.3w stereo speaker amplifiers and directdrive headphone amplifiers with automatic level control 20 ______________________________________________________________________________________ max9756/ MAX9757/ max9758 r b 47k beep 0.47 f source 3 r b 47k 0.47 f source 2 r b 47k 0.47 f source 1 47k bias window detector (0.3v p-p threshold) frequency detector (300hz threshold) speaker/headphone amplifier inputs v beep figure 12. beep input table 5. beep output gain a v(beepout) headphone * (v/v) speaker* (v/v) gain3 gain2 gain1 1.5 8.4 0 0 0 1.5 9.4 0 0 1 1.78 10 0 1 0 1.78 10 0 1 1 1.5 15.8 1 0 0 1.5 18.8 1 0 1 1.78 20 1 1 0 1.78 20 1 1 1 * all output gains are for v vol = gnd.
shutdown ( shdn ) the max9756/MAX9757/max9758 feature a 0.2?, low-power shutdown mode that reduces quiescent cur- rent consumption and extends battery life. driving shdn low disables the drive amplifiers, bias circuitry, and charge pump, and drives bias and all outputs to gnd. connect shdn to v dd for normal operation. click-and-pop suppression speaker amplifier the max9756/MAX9757/max9758 speaker amplifiers feature maxim? comprehensive, industry-leading click- and-pop suppression. during startup, the click-and- pop suppression circuitry eliminates any audible transient sources internal to the device. when entering shutdown, both amplifier outputs ramp to gnd quickly and simultaneously. headphone amplifier in conventional single-supply headphone amplifiers, the output-coupling capacitor is a major contributor of audi- ble clicks and pops. since the max9756/MAX9757/ max9758 do not require output-coupling capacitors, no audible transient occurs. additionally, the max9756/MAX9757/max9758 feature extensive click-and-pop suppression that eliminates any audible transient sources internal to the device. the turn-on/turn-off waveforms in the typical operating characteristics show that there are minimal spectral components in the audible range at the output upon startup and shutdown. applications information btl speaker amplifiers the max9756/MAX9757/max9758 feature speaker amplifiers designed to drive a load differentially, a config- uration referred to as bridge-tied load (btl). the btl configuration (figure 13) offers advantages over the sin- gle-ended configuration, where one side of the load is connected to ground. driving the load differentially dou- bles the output voltage compared to a single-ended amplifier under similar conditions. since the differential outputs are biased at 2.5v, there is no net dc voltage across the load. this eliminates the need for dc-blocking capacitors required for single- ended amplifiers. these capacitors can be large and expensive, can consume board space, and can degrade low-frequency performance. power dissipation and heat sinking under normal operating conditions, the max9756/ MAX9757/max9758 can dissipate a significant amount of power. the maximum power dissipation for each package is given in the absolute maximum ratings under continuous power dissipation, or can be calcu- lated by the following equation: where t j(max) is +150?, t a is the ambient temperature, and ja is the reciprocal of the derating factor in ?/w as specified in the absolute maximum ratings section. for example, ja of the 32-pin thin qfn package is +40.2?/w. for optimum power dissipation, the exposed paddle of the package should be connected to the ground plane (see the layout and grounding section). output power (speaker amplifier) the increase in power delivered by the btl configura- tion directly results in an increase in internal power dis- sipation over the single-ended configuration. the maximum power dissipation for a given v dd and load is given by the following equation: if the power dissipation for a given application exceeds the maximum allowed for a given package, either reduce v dd , increase load impedance, decrease the ambient temperature, or add heatsinking to the device or setting pref to limit output power to a safe level. large output, supply, and ground pc board traces improve the maxi- mum power dissipation in the package. thermal-over- load protection limits total power dissipation in these devices. when the junction temperature exceeds +160?, the thermal-protection circuitry disables the amplifier output stage. the amplifiers are enabled once the junction temperature cools by 15?. this results in a pulsing output under continuous thermal-overload condi- tions as the device heats and cools. p v r diss max dd l () = 2 2 2 p t disspkg max j max t a ja () () = ? max9756/MAX9757/max9758 2.3w stereo speaker amplifiers and directdrive headphone amplifiers with automatic level control ______________________________________________________________________________________ 21 figure 13. bridge-tied load configuration +1 v out(p-p) 2 x v out(p-p) v out(p-p) -1
max9756/MAX9757/max9758 output power (headphone amplifier) the headphone amplifiers have been specified for the worst-case scenario?hen both inputs are in phase. under this condition, the drivers simultaneously draw current from the charge pump, leading to a slight loss in headroom of v ss . in typical stereo audio applica- tions, the left and right signals have differences in both magnitude and phase, subsequently leading to an increase in the maximum attainable output power. figure 14 shows the two extreme cases for in and out of phase. in reality, the available power lies between these extremes. power supplies the max9756/MAX9757/max9758 have different sup- plies for each portion of the device, allowing for the opti- mum combination of headroom and power dissipation and noise immunity. the speaker amplifiers are pow- ered from pv dd . pv dd ranges from 4.5v to 5.5v. the headphone amplifiers are powered from hpv dd and v ss . hpv dd is the positive supply of the headphone amplifiers and ranges from 3v to 5.5v. v ss is the nega- tive supply of the headphone amplifiers. connect v ss to cpv ss . the charge pump is powered by cpv dd . cpv dd ranges from 3v to 5.5v and should be the same potential as hpv dd . the charge pump inverts the volt- age at cpv dd , and the resulting voltage appears at cpv ss . the remainder of the device is powered by v dd . component selection input filtering the input capacitor (c in ), in conjunction with the ampli- fier input resistance (r in ), forms a highpass filter that removes the dc bias from an incoming signal (see the typical application circuit ). the ac-coupling capacitor allows the amplifier to bias the signal to an optimum dc level. assuming zero source impedance, the -3db point of the highpass filter is given by: r in is the amplifier? internal input resistance value given in the electrical characteristics . choose c in such that f -3db is well below the lowest frequency of interest. setting f -3db too high affects the amplifier? low-fre- quency response. use capacitors with low-voltage coefficient dielectrics, such as tantalum or aluminum electrolytic. capacitors with high-voltage coefficients, such as ceramics, may result in increased distortion at low frequencies. bias capacitor bias is the output of the internally generated dc bias voltage. the bias bypass capacitor, c bias , improves psrr and thd+n by reducing power supply and other noise sources at the common-mode bias node, and also generates the startup/shutdown dc bias wave- forms for the speaker amplifiers. bypass bias with a 1? capacitor to gnd. charge-pump capacitor selection use capacitors with an esr less than 100m for opti- mum performance. low-esr ceramic capacitors mini- mize the output resistance of the charge pump. for best performance over the extended temperature range, select capacitors with an x7r dielectric. table 6 lists suggested manufacturers. f rc db in in ? = 3 1 2 2.3w stereo speaker amplifiers and directdrive headphone amplifiers with automatic level control 22 ______________________________________________________________________________________ output power (mw) thd+n (%) 160 140 100 120 60 80 20 40 0.01 0.1 1 10 100 0.001 0 200 180 hpv dd = 5v r l = 16 outputs 180 out of phase outputs in phase figure 14. total harmonic distortion plus noise vs. output power with inputs in/out of phase (headphone mode) table 6. suggested capacitor manufacturers supplier phone fax website taiyo yuden 800-384-2496 800-925-0899 www.t-yuden.com tdk 807-803-6100 847-390-4405 www.component.tdk.com
flying capacitor (c1) the value of the flying capacitor (c1) affects the load regulation and output resistance of the charge pump. a c1 value that is too small degrades the device? ability to provide sufficient current drive, which leads to a loss of output voltage. increasing the value of c1 improves load regulation and reduces the charge-pump output resis- tance to an extent. see the output power vs. charge- pump capacitance graph in the typical operating characteristics . above 2.2?, the on-resistance of the switches and the esr of c1 and c2 dominate. output capacitor (c2) the output capacitor value and esr directly affect the ripple at cpv ss . increasing the value of c2 reduces output ripple. likewise, decreasing the esr of c2 reduces both ripple and output resistance. lower capacitance values can be used in systems with low maximum output power levels. see the output power vs. charge-pump capacitance graph in the typical operating characteristics . cpv dd bypass capacitor the cpv dd bypass capacitor (c3) lowers the output impedance of the power supply and reduces the impact of the max9756/MAX9757/max9758? charge-pump switching transients. bypass cpv dd with c3, the same value as c1, and place it physically close to cpv dd and pgnd (refer to the max9756/MAX9757/max9758 evaluation kit for a suggested layout). powering other circuits from a negative supply an additional benefit of the max9756/MAX9757/ max9758 is the internally generated negative supply voltage (cpv ss ). cpv ss is used by the max9756/ MAX9757/max9758 to provide the negative supply for the headphone amplifiers. it can also be used to power other devices within a design. current draw from cpv ss should be limited to 5ma; exceeding this affects the operation of the headphone amplifier. a typical application is a negative supply to adjust the contrast of lcd modules. when considering the use of cpv ss in this manner, note that the charge-pump voltage of cpv ss is roughly proportional to cpv dd and is not a regulated voltage. layout and grounding proper layout and grounding are essential for optimum performance. use large traces for the power-supply inputs and amplifier outputs to minimize losses due to parasitic trace resistance, as well as route heat away from the device. good grounding improves audio per- formance, minimizes crosstalk between channels, and prevents any switching noise from coupling into the audio signal. connect cpgnd, pgnd, and gnd together at a single point on the pc board. route cpgnd and all traces that carry switching transients away from gnd, pgnd, and the traces and compo- nents in the audio signal path. connect all components associated with the charge pump (c2 and c3) to the cpgnd plane. connect v ss and cpv ss together at the device. place the charge- pump capacitors (c1, c2, and c3) as close to the device as possible. bypass hpv dd and pv dd with a 1? capacitor to gnd. place the bypass capacitors as close to the device as possible. use large, low-resistance output traces. as load imped- ance decreases, the current drawn from the device out- puts increase. at higher current, the resistance of the output traces decrease the power delivered to the load. for example, when compared to a 0 trace, a 100m trace reduces the power delivered to a 4 load from 2.1w to 2w. large output, supply, and gnd traces also improve the power dissipation of the device. the max9756/MAX9757/max9758 thin qfn package fea- tures an exposed thermal pad on its underside. this pad lowers the package? thermal resistance by providing a direct-heat conduction path from the die to the pc board. connect the exposed thermal pad to gnd by using a large pad and multiple vias to the gnd plane . max9756/MAX9757/max9758 2.3w stereo speaker amplifiers and directdrive headphone amplifiers with automatic level control ______________________________________________________________________________________ 23
max9756/MAX9757/max9758 2.3w stereo speaker amplifiers and directdrive headphone amplifiers with automatic level control 24 ______________________________________________________________________________________ max9756 block diagram hpv dd hps inr bias vol gain1 gain2 beep 3v to 5.5v cpv dd c1p c1n c1 1 f c bias 1 f 0v to hpv dd c in 1 f c in 1 f 0.47 f 1 f cpgnd inl 36 26 28 2 3 5 10 11 13 12 cpv ss 14 v ss v dd v dd 15 regen 24 in 33 31 6, 22 34 out 4.65v output to codec 30 set 1 dr 25 ct 35 pref 29 1 f 3v to 5.5v 7 32 8 21 20 18 23 17 16 hpl hpr max9756 0.1 f0.1 f gain/ volume control btl amplifier right- channel audio input outr+ outr- charge pump volume and gain control headphone detection shutdown control beep detection gain/ volume btl amplifier left-channel audio input outl+ 4.5v to 5.5v v dd outl- peak detect gain3 shdn 4 27 9, 19 100 f 4.5v to 5.5v pv dd r b 47k figure shown with an attack time = 495 s, release time = 990ms and an output power limit set to 1.2w, spkr gain = 25.5db, ldo shown in fixed output mode, hpgain = 3db . 0.033 f c1 1 f gnd pgnd ldo c3, c4 1 f 1 f1 f 180k
max9756/MAX9757/max9758 2.3w stereo speaker amplifiers and directdrive headphone amplifiers with automatic level control ______________________________________________________________________________________ 25 MAX9757 block diagram hpv dd hps inr bias vol gain1 gain2 beep 3v to 5.5v cpv dd c1p c1n c1 1 f c bias 1 f 0v to hpv dd c in 1 f c in 1 f 0.47 f 1 f cpgnd inl 31 26 28 1 2 4 9 10 12 11 cpv ss 13 v ss v dd 14 28 5, 21 32 1 f 3v to 5.5v 6 29 7 20 19 17 22 15 16 hpl hpr MAX9757 0.1 f 0.1 f gain/ volume control btl amplifier right- channel audio input outr+ outr- charge pump volume and gain control headphone detection shutdown control beep detection gain/ volume btl amplifier left-channel audio input outl+ 4.5v to 5.5v v dd outl- peak detect gain3 shdn 3 25 8, 18 100 f 4.5v to 5.5v pv dd r b 47k figure shown with an attack time = 495 s, release time = 990ms and an output power limit set to 1.2w, spkr gain = 25.5db, hp gain = 3db. 100 f 180k c2 1 f gnd pgnd dr 23 ct 30 pref 27
max9756/MAX9757/max9758 2.3w stereo speaker amplifiers and directdrive headphone amplifiers with automatic level control 26 ______________________________________________________________________________________ max9758 block diagram hpv dd hps inr bias vol gain1 gain2 beep 3v to 5.5v cpv dd c1p c1n c1 1 f c bias 1 f 0v to hpv dd c in 1 f c in 1 f 0.47 f 1 f cpgnd inl 31 24 26 1 2 4 9 10 12 11 cpv ss 13 v ss v dd v dd 14 regen 23 28 5, 21 30 out 27 set 32 1 f 3v to 5.5v 6 29 7 20 19 17 22 15 16 hpl hpr max9758 0.1 f0.1 f volume btl amplifier right-channel audio input outr+ outr- charge pump volume and gain control headphone detection shutdown control beep detection volume btl amplifier left-channel audio input outl+ 4.5v to 5.5v v dd outl- gain3 shdn 3 25 8, 18 100 f 4.5v to 5.5v pv dd r b figure shown with spkr gain = 25.5db, ldo shown in adjustable output mode set to 3.3v, hp gain = 3db. c2 1 f gnd pgnd ldo 1 f 82k 47k 1 f 3.3v output to codec 10pf
max9756/MAX9757/max9758 2.3w stereo speaker amplifiers and directdrive headphone amplifiers with automatic level control ______________________________________________________________________________________ 27 system diagram codec 3v to 5.5v max9756 inr 4.5v to 5.5v 3v to 5.5v inl cpv dd regen out beep 1 f 1 f 180k 1 f 1 f 0.033 f 0.1 f 1 f 1 f 1 f c c1p c1n pref bias gnd pgnd shdn outl+ outl- vol cpv ss v ss set bias outr+ gain1 gain2 outr- hpl hps hpr v dd hpv dd pv dd in 10 f cpgnd hpv dd 1 f 47k gain3 dr ct 1 f
max9756/MAX9757/max9758 2.3w stereo speaker amplifiers and directdrive headphone amplifiers with automatic level control 28 ______________________________________________________________________________________ pin configurations 27 26 24 23 22 21 25 20 19 hpv dd hpl v ss cpv ss c1p cpv dd c1n cpgnd hpr set gnd v dd out ct inr vol 28 29 30 31 32 33 34 35 36 18 17 16 15 14 13 12 11 10 beep pgnd outl+ pv dd gain3 gain2 gain1 inl bias dr regen hps pgnd outr+ outr- pv dd shdn tqfn 6mm x 6mm max9756 top view 1 2 4 5 6 7 3 89 in outl- pref MAX9757 thin qfn 5mm x 5mm 29 30 28 27 12 11 13 gain2 beep pgnd outl+ outl- 14 gain1 dr pgnd outr+ bias outr- pv dd 12 gnd 4567 23 24 22 20 19 18 v dd ct v ss cpv ss c1n cpgnd gain3 hps 3 21 31 10 inr c1p 32 9 inl cpv dd pref 26 15 hpr vol 25 16 hpl pv dd hpv dd 8 17 shdn max9758 thin qfn 5mm x 5mm 29 30 28 27 12 11 13 gain2 beep pgnd outl+ outl- 14 gain1 regen pgnd outr+ bias outr- pv dd 12 gnd 4567 23 24 22 20 19 18 v dd out v ss cpv ss c1n cpgnd gain3 hps 3 21 31 10 inr c1p 32 9 inl cpv dd set 26 15 hpr vol 25 16 hpl pv dd hpv dd 8 17 shdn chip information process: bicmos
max9756/MAX9757/max9758 2.3w stereo speaker amplifiers and directdrive headphone amplifiers with automatic level control ______________________________________________________________________________________ 29 package information (the package drawing(s) in this data sheet may not reflect the most current specifications. for the latest package outline info rmation go to www.maxim-ic.com/packages .) qfn thin.eps d2 (nd-1) x e e d c pin # 1 i.d. (ne-1) x e e/2 e 0.08 c 0.10 c a a1 a3 detail a e2/2 e2 0.10 m c a b pin # 1 i.d. b 0.35x45 d/2 d2/2 l c l c e e l c c l k l l detail b l l1 e aaaaa marking i 1 2 21-0140 package outline, 16, 20, 28, 32, 40l thin qfn, 5x5x0.8mm -drawing not to scale- l e/2
max9756/MAX9757/max9758 2.3w stereo speaker amplifiers and directdrive headphone amplifiers with automatic level control 30 ______________________________________________________________________________________ package information (continued) (the package drawing(s) in this data sheet may not reflect the most current specifications. for the latest package outline info rmation go to www.maxim-ic.com/packages .) common dimensions max. exposed pad variations d2 nom. min. min. e2 nom. max. ne nd pkg. codes 1. dimensioning & tolerancing conform to asme y14.5m-1994. 2. all dimensions are in millimeters. angles are in degrees. 3. n is the total number of terminals. 4. the terminal #1 identifier and terminal numbering convention shall conform to jesd 95-1 spp-012. details of terminal #1 identifier are optional, but must be located within the zone indicated. the terminal #1 identifier may be either a mold or marked feature. 5. dimension b applies to metallized terminal and is measured between 0.25 mm and 0.30 mm from terminal tip. 6. nd and ne refer to the number of terminals on each d and e side respectively. 7. depopulation is possible in a symmetrical fashion. 8. coplanarity applies to the exposed heat sink slug as well as the terminals. 9. drawing conforms to jedec mo220, except exposed pad dimension for t2855-3 and t2855-6. notes: symbol pkg. n l1 e e d b a3 a a1 k 10. warpage shall not exceed 0.10 mm. jedec 0.70 0.80 0.75 4.90 4.90 0.25 0.25 0 -- 4 whhb 4 16 0.35 0.30 5.10 5.10 5.00 0.80 bsc. 5.00 0.05 0.20 ref. 0.02 min. max. nom. 16l 5x5 l 0.30 0.50 0.40 -- - -- - whhc 20 5 5 5.00 5.00 0.30 0.55 0.65 bsc. 0.45 0.25 4.90 4.90 0.25 0.65 - - 5.10 5.10 0.35 20l 5x5 0.20 ref. 0.75 0.02 nom. 0 0.70 min. 0.05 0.80 max. -- - whhd-1 28 7 7 5.00 5.00 0.25 0.55 0.50 bsc. 0.45 0.25 4.90 4.90 0.20 0.65 - - 5.10 5.10 0.30 28l 5x5 0.20 ref. 0.75 0.02 nom. 0 0.70 min. 0.05 0.80 max. -- - whhd-2 32 8 8 5.00 5.00 0.40 0.50 bsc. 0.30 0.25 4.90 4.90 0.50 - - 5.10 5.10 32l 5x5 0.20 ref. 0.75 0.02 nom. 0 0.70 min. 0.05 0.80 max. 0.20 0.25 0.30 down bonds allowed yes 3.10 3.00 3.20 3.10 3.00 3.20 t2055-3 3.10 3.00 3.20 3.10 3.00 3.20 t2055-4 t2855-3 3.15 3.25 3.35 3.15 3.25 3.35 t2855-6 3.15 3.25 3.35 3.15 3.25 3.35 t2855-4 2.60 2.70 2.80 2.60 2.70 2.80 t2855-5 2.60 2.70 2.80 2.60 2.70 2.80 t2855-7 2.60 2.70 2.80 2.60 2.70 2.80 3.20 3.00 3.10 t3255-3 3 .20 3.00 3.10 3.20 3.00 3.10 t3255-4 3 .20 3.00 3.10 no no no no yes yes yes yes 3.20 3.00 t1655-3 3.10 3.00 3.10 3.20 no no 3.20 3.10 3.00 3.10 t1655n-1 3.00 3.20 3.35 3.15 t2055-5 3.25 3.15 3.25 3.35 yes 3.35 3.15 t2855n-1 3.25 3.15 3.25 3.35 no 3.35 3.15 t2855-8 3.25 3.15 3.25 3.35 yes 3.20 3.10 t3255n-1 3.00 no 3.20 3.10 3.00 l 0.40 0.40 ** ** ** ** ** ** ** ** ** ** ** ** ** ** see common dimensions table 0.15 11. marking is for package orientation reference only. i 2 2 21-0140 package outline, 16, 20, 28, 32, 40l thin qfn, 5x5x0.8mm -drawing not to scale- 12. number of leads shown are for reference only. 3.30 t4055-1 3.20 3.40 3.20 3.30 3.40 ** yes 0.05 0 0.02 0.60 0.40 0.50 10 ----- 0.30 40 10 0.40 0.50 5.10 4.90 5.00 0.25 0.35 0.45 0.40 bsc. 0.15 4.90 0.25 0.20 5.00 5.10 0.20 ref. 0.70 min. 0.75 0.80 nom. 40l 5x5 max. 13. lead centerlines to be at true position as defined by basic dimension "e", 0.05. t1655-2 ** yes 3.20 3.10 3.00 3.10 3.00 3.20 t3255-5 yes 3.00 3.10 3.00 3.20 3.20 3.10 ** exceptions
max9756/MAX9757/max9758 2.3w stereo speaker amplifiers and directdrive headphone amplifiers with automatic level control quijano maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a maxim product. no circu it patent licenses are implied. maxim reserves the right to change the circuitry and specifications without notice at any time. 31 ____________________maxim integrated products, 120 san gabriel drive, sunnyvale, ca 94086 408-737-7600 2005 maxim integrated products printed usa is a registered trademark of maxim integrated products, inc. package information (continued) (the package drawing(s) in this data sheet may not reflect the most current specifications. for the latest package outline info rmation go to www.maxim-ic.com/packages .) qfn thin.eps e e l l a1 a2 a e/ 2 e d/2 d e2/2 e2 (ne-1) x e (nd-1) x e e d2/2 d2 b k k l c l c l c l c l f 1 2 21-0141 package outline 36, 40, 48l thin qfn, 6x6x0.8m m l1 l e 8. coplanarity applies to the exposed heat sink slug as well as the terminals. 6. nd and ne refer to the number of terminals on each d and e side respectively. 5. dimension b applies to metallized terminal and is measured between 0.25 mm and 0.30 mm from terminal tip. 4. the terminal #1 identifier and terminal numbering convention shall conform to jesd 95-1 spp-012. details of terminal #1 identifier are optional, but must be located within the zone indicated. the terminal #1 identifier may be either a mold or marked feature. 9. drawing conforms to jedec mo220, except for 0.4mm lead pitch package t4866-1. 7. depopulation is possible in a symmetrical fashion. 3. n is the total number of terminals. 2. all dimensions are in millimeters. angles are in degrees. 1. dimensioning & tolerancing conform to asme y14.5m-1994. notes: 10. warpage shall not exceed 0.10 mm. f 2 2 21-0141 package outline 36, 40, 48l thin qfn, 6x6x0.8m m 11. marking is for package orientation reference only. 12. number of leads shown for reference only.

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