View MAX8805Z_3415636.PDF datasheet online --- IC-ON-LINE

Datasheet File OCR Text:

general description the max8805y/MAX8805Z high-frequency step-down converters are optimized for dynamically powering the power amplifier (pa) in wcdma or ncdma handsets. the devices integrate a high-efficiency pwm step-down converter for medium- and low-power transmission, and a 60m typical bypass fet to power the pa directly from the battery during high-power transmission. dual 200ma low-noise, high-psrr low-dropout regulators (ldos) for pa biasing are also integrated. two switching frequency options are available?mhz (max8805y) and 4mhz (MAX8805Z)?llowing optimiza- tion for smallest solution size or highest efficiency. fast switching allows the use of small ceramic 2.2? input and output capacitors while maintaining low ripple voltage. the feedback network is integrated, further reducing external component count and total solution size. the max8805y/MAX8805Z use an analog input driven by an external dac to control the output voltage linearly for continuous pa power adjustment. at high duty cycle, the max8805y/MAX8805Z automatically switch to the bypass mode, connecting the input to the output through a low-impedance (60m typ) mosfet. the user can also enable the bypass mode directly through a logic-control input. the ldos in the max8805y/MAX8805Z are designed for low-noise operation (35? rms typ). each ldo is indi- vidually enabled through its own logic control interface. the max8805y/MAX8805Z are available in a 16-bump, 2mm x 2mm wlp package (0.7mm max height). applications wcdma/ncdma cellular handsets wireless pdas smartphones features ? pa step-down converter 7.5? (typ) settling time for 0.8v to 3.4v output voltage change dynamic output voltage setting from 0.4v to v batt 60m pfet and 100% duty cycle for low dropout 2mhz or 4mhz switching frequency low output-voltage ripple 600ma output drive capability 2% maximum accuracy tiny external components ? dual low-noise ldos low 35? rms (typ) output noise high 70db (typ) psrr guaranteed 200ma output drive capability individual on/off control ? low 0.1? shutdown current ? 2.7v to 5.5v supply voltage range ? thermal shutdown ? tiny 2mm x 2mm x 0.7mm wlp package (4 x 4 grid) max8805y/MAX8805Z 600ma pwm step-down converters in 2mm x 2mm wlp for wcdma pa power ________________________________________________________________ maxim integrated products 1 ordering information in1a lx paa 1 h batt 2.7v to 5.5v agnd pa_en refin en1 en2 in2 batt 2.7v to 5.5v pa on/off analog control v pa 0.4v to v batt refbp in1b ldo1 on/off ldo2 on/off pab ldo2 ldo1 v ldo2 up to 200ma pgnd hp forced bypass 2.2 f 2.2 f MAX8805Z v ldo1 up to 200ma typical operating circuit 19-0777; rev 0; 4/07 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. + denotes a lead-free package. t = tape and reel package. * xy is the output voltage code (see table 1 in the output voltages section). note: all devices are specified over the -40? to +85? operat- ing temperature range. pin configuration appears at end of data sheet. part pin- package pkg code swi t c h i n g f r eq u en c y ( m h z) max8805y ewexy+t* 16 wlp-16 w162b2+ 1 2 MAX8805Z ewexy+t* 16 wlp-16 w162b2+ 1 4
max8805y/MAX8805Z 600ma pwm step-down converters in 2mm x 2mm wlp for wcdma pa power 2 _______________________________________________________________________________________ absolute maximum ratings electrical characteristics (v in1a = v in1b = v in2 = v pa_en = v en1 = v en2 = 3.6v, v hp = 0v, v refin = 0.9v, t a = -40? to +85?. typical values are at t a = +25?, unless otherwise noted.) (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. in1a, in1b, in2, refin, en2, refbp to agnd ...-0.3v to +6.0v paa, pab, pa_en, hp to agnd....-0.3v to (v in1a /v in1b + 0.3v) ldo1, ldo2, en1 to agnd ......................-0.3v to (v in2 + 0.3v) in2 to in1b/in1a ...................................................-0.3v to +0.3v pgnd to agnd .....................................................-0.3v to +0.3v lx current ......................................................................0.7a rms in1a/in1b and paa/pab current .....................................2a rms paa and pab short circuit to gnd or in...................continuous continuous power dissipation (t a = +70?) 16-bump wlp (derate 12.5mw/? above +70?).............1w junction temperature ......................................................+150? storage temperature range .............................-65? to +150? bump temperature (soldering, reflow) ............................+235? parameter conditions min typ max units input supply input voltage v in1a , v in1b , v in2 2.7 5.5 v input undervoltage threshold v in1a , v in1b , v in2 rising, 180mv typical hysteresis 2.52 2.63 2.70 v t a = +25? 0.1 4 shutdown supply current v pa_en = v en1 = v en2 = 0v t a = +85? 0.1 ? v pa_en = 0v, i ldo1 = i ldo2 = 0a 150 250 max8805y 3500 v en1 = v en2 = 0v, i pa = 0a, switching MAX8805Z 5000 no-load supply current v en1 = v en2 = 0v, v hp = 3.6v 150 ? thermal protection thermal shutdown t a rising, 20? typical hysteresis +160 ? logic control pa_en, en1, en2, hp logic- input high voltage 2.7v v in1a = v in1b = v in2 5.5v 1.4 v pa_en, en1, en2, hp logic- input low voltage 2.7v v in1a = v in1b = v in2 5.5v 0.4 v t a = +25? 0.01 1 logic-input current (pa_en, en1, en2, hp) v il = 0v or v ih = v in1a = 5.5v t a = +85? 0.1 ? refin refin common-mode range 0.1 2.2 v refin to pa_ gain (falling edge) v refin = 0.4v, 0.9v, 1.7v, 2.2v 1.96 2.00 2.04 v/v refin input resistance 540 k refin dual mode threshold v refin rising, 50mv hysteresis 0.45 x v in2 0.465 x v in2 0.48 x v in2 v note: this device is constructed using a unique set of packaging techniques that impose a limit on the thermal profile the device can be exposed to during board level solder attach and rework. this limit permits only the use of the solder profiles recom- mended in the industry-standard specification, jedec 020a, paragraph 7.6, table 3 for ir/vpr and convection reflow. preheating is required. hand or wave soldering is not allowed. dual mode is a trademark of maxim integrated products, inc.
max8805y/MAX8805Z 600ma pwm step-down converters in 2mm x 2mm wlp for wcdma pa power _______________________________________________________________________________________ 3 parameter conditions min typ max units lx p-channel mosfet switch, i lx = -40ma 0.18 0.6 on-resistance n-channel mosfet rectifier, i lx = 40ma 0.15 0.6 t a = +25? 0.1 5 lx leakage current v in1a = v in1b = v in2 = 5.5v, v lx = 0v t a = +85? 1 ? p-channel mosfet peak current limit v lx = 0v 0.7 0.9 1.1 a n-channel mosfet valley current limit 0.5 0.7 0.9 a minimum on- and off-times 0.1 ? power-up delay from pa_en rising to lx rising 150 250 ? bypass t a = +25? 0.060 0.1 on-resistance p-channel mosfet bypass, i out = -90ma t a = +85? 0.1 bypass current limit v pa = 0 0.8 1.2 1.8 a s tep - d ow n c ur r ent li m i t i n byp ass v lx = 0 0.7 0.9 1.1 a total bypass current limit v lx = v pa = 0 1.5 2.1 2.9 a t a = +25? 0.01 10 bypass off-leakage current v in1a = v in1b = v in2 = 5.5v, v paa = v pab = 0v t a = +85? 1 ? ldo1 max8805yeweaa+t 1.746 1.8 1.854 max8805yewebc+t 2.425 2.5 2.575 max8805yewecc+t 2.619 2.7 2.781 max8805yewedd+t 2.716 2.8 2.884 max8805yeweee+t 2.765 2.85 2.936 output voltage v ldo1 v in2 = 5.5v, i ldo1 = 1ma; v in2 = 3.4v, i ldo1 = 100ma max8805yewegg+t 2.910 3.0 3.090 v output current 200 ma current limit v ldo1 = 0v 250 550 750 ma dropout voltage i ldo1 = 100ma, t a = +25? (v ldo1 2.5v) 70 200 mv line regulation v in2 stepped from 3.5v to 5.5v, i ldo1 = 100ma 2.4 mv load regulation i ldo1 stepped from 50? to 200ma 25 mv power-supply rejection v ldo1 / v in2 10hz to 10khz, c ldo1 = 1?, i ldo1 = 30ma 70 db output noise 100hz to 100khz, c ldo1 = 1?, i ldo1 = 30ma 35 v rms 0 < i ldo1 < 10ma 100 nf output capacitor for stable operation 0 < i ldo1 < 200ma 1 ? shutdown output impedance v en1 = 0v 1 k electrical characteristics (continued) (v in1a = v in1b = v in2 = v pa_en = v en1 = v en2 = 3.6v, v hp = 0v, v refin = 0.9v, t a = -40? to +85?. typical values are at t a = +25?, unless otherwise noted.) (note 1)
max8805y/MAX8805Z 600ma pwm step-down converters in 2mm x 2mm wlp for wcdma pa power 4 _______________________________________________________________________________________ electrical characteristics (continued) (v in1a = v in1b = v in2 = v pa_en = v en1 = v en2 = 3.6v, v hp = 0v, v refin = 0.9v, t a = -40? to +85?. typical values are at t a = +25?, unless otherwise noted.) (note 1) parameter conditions min typ max units ldo2 max8805yeweaa+t 1.746 1.8 1.854 max8805yeweac+t 2.619 2.7 2.781 max8805yewead+t 2.716 2.8 2.884 max8805yewebe+t 2.765 2.85 2.936 output voltage v ldo2 v in2 = 5.5v, i ldo2 = 1ma; v in2 = 3.4v, i ldo2 = 100ma max8805yewegg+t 2.910 3.0 3.090 v output current 200 ma current limit v ldo2 = 0v 250 550 750 ma dropout voltage i ldo2 = 100ma, t a = +25? 70 200 mv line regulation v in2 stepped from 3.5v to 5.5v, i ldo2 = 100ma 2.4 mv load regulation i ldo2 stepped from 50? to 200ma 25 mv power-supply rejection v ldo2 / v in2 10hz to 10khz, c ldo2 = 1?, i ldo2 = 30ma 70 db output noise 100hz to 100khz, c ldo2 = 1?, i ldo2 = 30ma 35 v rms 0? < i ldo2 < 10ma 100 nf output capacitor for stable operation 0? < i ldo2 < 200ma 1 ? shutdown output impedance v en2 = 0v 1 k refbp refbp output voltage 0 i refbp 1? 1.237 1.250 1.263 v refbp supply rejection v in2 stepped from 2.55v to 5.5v 0.2 5 mv note 1: all devices are 100% production tested at t a = +25?. limits over the operating temperature range are guaranteed by design.
max8805y/MAX8805Z 600ma pwm step-down converters in 2mm x 2mm wlp for wcdma pa power _______________________________________________________________________________________ 5 typical operating characteristics (v in1a = v in1b = v in2 = 3.6v, v pa = 1.2v, v ldo1 = 2.85v, v ldo2 = 2.85v, r pa = 7.5 , circuit of figure 5, t a = +25?, unless other- wise noted.) 0 40 20 80 60 120 100 140 0 0.4 0.6 0.2 0.8 1.0 1.2 1.4 1.6 1.8 bypass mode dropout voltage vs. pa load current max8805y/z toc01 pa load current (a) bypass mode dropout voltage (mv) v in1 = 3.2v v in1 = 3.6v 60 70 80 90 100 0.5 1.5 2.5 3.5 1.0 2.0 3.0 4.0 4.5 pa step-down converter efficiency vs. output voltage (MAX8805Z) max8805y/z toc02 output voltage (v) efficiency (%) bypass mode v in1 = 4.2v v in1 = 3.6v v in1 = 3.2v r pa = 7.5 60 70 80 90 100 0.5 1.5 2.5 3.5 1.0 2.0 3.0 4.0 4.5 pa step-down converter efficiency vs. output voltage (max8805y) max8805y/z toc03 output voltage (v) efficiency (%) bypass mode v in1 = 4.2v v in1 = 3.6v v in1 = 3.2v r pa = 7.5 60 70 80 90 100 0.5 1.5 2.5 3.5 1.0 2.0 3.0 4.0 4.5 pa step-down converter efficiency vs. output voltage (MAX8805Z) max8805y/z toc04 output voltage (v) efficiency (%) bypass mode v in1 = 4.2v v in1 = 3.6v v in1 = 3.2v r pa = 10 60 70 80 90 100 0.5 1.5 2.5 3.5 1.0 2.0 3.0 4.0 4.5 pa step-down converter efficiency vs. output voltage (max8805y) max8805y/z toc05 output voltage (v) efficiency (%) bypass mode v in1 = 4.2v v in1 = 3.6v v in1 = 3.2v r pa = 10 50 60 80 70 90 100 0200 100 300 400 500 600 pa step-down converter efficiency vs. load current (MAX8805Z) max8805y/z toc06 load current (ma) efficiency (%) v in1 = 4.2v v in1 = 3.6v v in1 = 3.2v v pa = 1.8v 50 60 80 70 90 100 0 200 100 300 500 400 600 pa step-down converter efficiency vs. load current (max8805y) max8805y/z toc07 load current (ma) efficiency (%) v in1 = 4.2v v in1 = 3.6v v in1 = 3.2v v pa = 1.8v 50 60 80 70 90 100 0200 100 300 500 400 600 pa step-down converter efficiency vs. load current (MAX8805Z) max8805y/z toc08 load current (ma) efficiency (%) v in1 = 4.2v v in1 = 3.6v v in1 = 3.2v v pa = 1.2v 50 60 80 70 90 100 0200 100 300 500 400 600 pa step-down converter efficiency vs. load current (max8805y) max8805y/z toc09 load current (ma) efficiency (%) v in1 = 4.2v v in1 = 3.6v v in1 = 3.2v v pa = 1.2v
max8805y/MAX8805Z 600ma pwm step-down converters in 2mm x 2mm wlp for wcdma pa power 6 _______________________________________________________________________________________ typical operating characteristics (continued) (v in1a = v in1b = v in2 = 3.6v, v pa = 1.2v, v ldo1 = 2.85v, v ldo2 = 2.85v, r pa = 7.5 , circuit of figure 5, t a = +25?, unless other- wise noted.) 50 60 80 70 90 100 0 200 100 300 500 400 600 pa step-down converter efficiency vs. load current (MAX8805Z) max8805y/z toc10 load current (ma) efficiency (%) v in1 = 4.2v v in1 = 3.6v v in1 = 3.2v v pa = 0.6v 50 60 80 70 90 100 0 200 100 300 500 400 600 pa step-down converter efficiency vs. load current (max8805y) max8805y/z toc11 load current (ma) efficiency (%) v in1 = 4.2v v in1 = 3.6v v in1 = 3.2v v pa = 0.6v 1.25 1.20 1.15 1.10 1.05 0 300 100 200 400 500 600 pa step-down converter output voltage vs. load current max8805y/z toc12 load current (ma) output voltage (v) max8805y MAX8805Z 0.5 1.5 1.0 2.5 2.0 3.5 3.0 4.0 00.8 0.4 1.2 1.6 2.0 pa step-down converter output voltage vs. refin voltage max8805y/z toc13 refin voltage (v) output voltage (v) -100 -60 -80 0 -20 -40 20 40 80 60 100 0.4 0.6 0.7 0.5 0.8 0.9 1.0 1.1 1.2 1.3 1.4 1.5 refin vs. refin to out gain (MAX8805Z) max8805y/z toc14 refin voltage (v) output voltage error (mv) v in1 = 3.2v, no load v in1 = 4.2v, no load -50 -30 -10 10 30 50 0.4 0.6 0.7 0.5 0.8 0.9 1.0 1.1 1.2 1.3 1.4 1.5 refin vs. refin to out gain (max8805y) max8805y/z toc15 refin voltage (v) output voltage error (mv) v in1 = 3.2v, no load v in1 = 4.2v, no load
400ns/div pa step-down converter light-load switching waveforms (MAX8805Z) v pa ac-coupled i lx 200ma/div 20mv/div 2v/div max8805y/z toc16 v lx v pa = 1.2v, i pa = 50ma 400ns/div pa step-down converter light-load switching waveforms (max8805y) v pa ac-coupled i lx 200ma/div 20mv/div 2v/div max8805y/z toc17 v lx v pa = 1.2v, i pa = 50ma 400ns/div pa step-down heavy-load switching waveforms (MAX8805Z) v pa ac-coupled i lx 500ma/div 20mv/div 2v/div max8805y/z toc18 v lx v pa = 1.2v, i pa = 500ma max8805y/MAX8805Z 600ma pwm step-down converters in 2mm x 2mm wlp for wcdma pa power _______________________________________________________________________________________ 7 400ns/div pa step-down heavy-load switching waveforms (max8805y) v pa ac-coupled i lx 500ma/div 20mv/div 2v/div max8805y/z toc19 v lx v pa = 1.2v, i pa = 500ma 20 s/div pa step-down soft-start waveforms (MAX8805Z) v pa_en v pa 1v/div 2v/div 500ma/div max8805y/z toc20 i lx 20 s/div pa step-down soft-start waveforms (max8805y) v pa_en v pa 1v/div 2v/div 200ma/div max8805y/z toc21 i lx typical operating characteristics (continued) (v in1a = v in1b = v in2 = 3.6v, v pa = 1.2v, v ldo1 = 2.85v, v ldo2 = 2.85v, r pa = 7.5 , circuit of figure 5, t a = +25?, unless other- wise noted.) _______________________________________________________________________________________ 7
max8805y/MAX8805Z 600ma pwm step-down converters in 2mm x 2mm wlp for wcdma pa power 8 _______________________________________________________________________________________ typical operating characteristics (continued) (v in1a = v in1b = v in2 = 3.6v, v pa = 1.2v, v ldo1 = 2.85v, v ldo2 = 2.85v, r pa = 7.5 , circuit of figure 5, t a = +25?, unless other- wise noted.) 10 s/div pa step-down converter output voltage transient response v refin v pa 500mv/div 500mv/div 500ma/div max8805y/z toc26 i lx 0.5v 1v 0.5v 20 s/div pa step-down converter forced bypass-fet transient response v hp v pa 2v/div 2v/div 500ma/div max8805y/z toc27 i lx 0.5v 0v 0v 1.2v 1.2v 3.6v 10 s/div pa step-down converter load transient response (max8805y) i pa i lx 500ma/div 500ma/div 100mv/div max8805y/z toc25 v pa ac-coupled 0ma 500ma 0ma 10 s/div pa step-down converter load transient response (MAX8805Z) i pa i lx 500ma/div 500ma/div 100mv/div max8805y/z toc24 v pa ac-coupled 0ma 500ma 0ma 10 s/div pa step-down converter line transient response (MAX8805Z) v in1 v pa ac-coupled 50mv/div 500mv/div 200ma/div max8805y/z toc22 i lx 4.0v 3.5v 4.0v 10 s/div pa step-down converter line transient response (max8805y) v in1 v pa ac-coupled 50mv/div 500mv/div 200ma/div max8805y/z toc23 i lx 4.0v 3.5v 4.0v
max8805y/MAX8805Z 600ma pwm step-down converters in 2mm x 2mm wlp for wcdma pa power _______________________________________________________________________________________ 9 10 s/div pa step-down converter automatic bypass-fet transient response v refin v pa 2v/div 1v/div 500ma/div max8805y/z toc28 i lx 1.8v 0.6v 0.6v 1.2v 1.2v 3.6v 200 s/div pa step-down converter automatic bypass-fet transient response v refin v pa 1v/div 1v/div 500ma/div max8805y/z toc29 i lx v refin is a 0.4v to 2v sinusoidal signal 3.6v 10 s/div pa step-down converter shutdown response (max8805y) v pa_en v pa 1v/div 2v/div 100ma/div max8805y/z toc30 i lx 0v 2v 1.2v 10 s/div pa step-down converter shutdown response (MAX8805Z) v pa_en v pa 2v/div 2v/div 100ma/div max8805y/z toc31 i lx 0v 2v 1.2v 0 50 100 150 200 ldo1, ldo2 supply current vs. supply voltage max8805y/z toc32 supply voltage (v) no-load supply current ( a) 2.0 3.5 4.0 2.5 3.0 4.5 5.0 5.5 0 30 90 60 120 150 ldo1, ldo2 dropout voltage vs. load current max8805y/z toc33 load current (ma) ldo1, ldo2 dropout voltage (mv) 0 100 50 150 200 typical operating characteristics (continued) (v in1a = v in1b = v in2 = 3.6v, v pa = 1.2v, v ldo1 = 2.85v, v ldo2 = 2.85v, r pa = 7.5 , circuit of figure 5, t a = +25?, unless other- wise noted.)
max8805y/MAX8805Z 600ma pwm step-down converters in 2mm x 2mm wlp for wcdma pa power 10 ______________________________________________________________________________________ 20 s/div ldo1, ldo2 load transient response near dropout 100ma/div 50mv/div 100ma/div max8805y/z toc38 0ma 80ma v in2 = v ldo1,2 + 200mv 50mv/div i ldo1 v ldo1 i ldo2 v ldo2 0ma 0ma 0ma 80ma 1ms/div ldo1, ldo2 turn on and shutdown response 2v/div 2v/div 2v/div max8805y/z toc39 v en1,2 v ldo1 v ldo2 20 s/div ldo line transient response 500mv/div max8805y/z toc37 4.0v 4.0v 3.5v i ldo_ = 80ma 5mv/div v in2 v ldo_ ldo psrr vs. frequency max8805y/z toc34 frequency (khz) psrr (db) 100 10 1 0.1 20 30 40 50 60 70 80 10 0.01 1000 i ldo = 30ma ldo output noise spectral density vs. frequency max8805y/z toc35 frequency (khz) output noise density noise (nv/ hz) 100 10 1 0.1 1.0e+02 1.0e+03 1.0e+04 1.0e+01 0.01 1000 400 s/div ldo1, ldo2 output noise waveform 50mv/div max8805y/z toc36 typical operating characteristics (continued) (v in1a = v in1b = v in2 = 3.6v, v pa = 1.2v, v ldo1 = 2.85v, v ldo2 = 2.85v, r pa = 7.5 , circuit of figure 5, t a = +25?, unless other- wise noted.)
max8805y/MAX8805Z 600ma pwm step-down converters in 2mm x 2mm wlp for wcdma pa power ______________________________________________________________________________________ 11 pin description pin name function a1 refbp reference noise bypass. bypass refbp to agnd with a 0.22? ceramic capacitor to reduce noise on the ldo outputs. refbp is internally pulled down through a 1k resistor during shutdown. a2 agnd low-noise analog ground a3 refin dac-controlled input. the output of the pa step-down converter is regulated to 2 x v refin . when v refin reaches 0.465 x v in2 , bypass mode is enabled. a4 pgnd power ground for pa step-down converter b1 ldo2 200ma ldo regulator 2 output. bypass ldo2 with a 1? ceramic capacitor as close as possible to ldo2 and agnd. ldo2 is internally pulled down through a 1k resistor when this regulator is disabled. b2 pa_en pa step-down converter enable input. connect to in_ or logic-high for normal operation. connect to gnd or logic-low for shutdown mode. b3 en2 ldo2 enable input. connect to in2 or logic-high for normal operation. connect to agnd or logic-low for shutdown mode. b4 lx inductor connection. connect an inductor from lx to the output of the pa step-down converter. c1 in2 supply voltage input for ldo1, ldo2, and internal reference. connect in2 to a battery or supply voltage from 2.7v to 5.5v. bypass in2 with a 2.2? ceramic capacitor as close as possible to in2 and agnd. connect in2 to the same source as in1a and in1b. c2 hp high-power mode set input. drive hp high to invoke forced bypass mode. bypass mode connects the input of the pa step-down converter directly to its output through the internal bypass mosfet. drive hp low to disable the forced bypass mode. c3, c4 in1b, in1a supply voltage input for pa step-down converter. connect in1_ to a battery or supply voltage from 2.7v to 5.5v. bypass the connection of in1_ with a 2.2? ceramic capacitor as close as possible to in1_, and pgnd. in1a and in1b are internally connected together. connect in1_ to the same source as in2. d1 ldo1 200ma ldo regulator 1 output. bypass ldo1 with a 1? ceramic capacitor as close as possible to ldo1 and agnd. ldo1 is internally pulled down through a 1k resistor when this regulator is disabled. d2 en1 ldo1 enable input. connect to in2 or logic-high for normal operation. connect to agnd or logic-low for shutdown mode. d3, d4 pab, paa pa connection for bypass mode. internally connected to in1_ using the internal bypass mosfet during bypass mode. pa_ is connected to the internal feedback network. bypass pa_ with a 2.2? ceramic capacitor as close as possible to pa_ and pgnd.
max8805y/MAX8805Z 600ma pwm step-down converters in 2mm x 2mm wlp for wcdma pa power 12 ______________________________________________________________________________________ pwm logic step-down current limit pwm error comparator current-limit control lx pgnd paa bypass fet hp refin r2 r1 r3 r5 r4 r6 r7 c2 c1 in2 r8 r7 error amp error amp ldo1 current limit ldo2 current limit bandgap bandgap ldo1 r11 r10 ldo2 r9 r12 1.25v reference control logic refbp agnd bandgap en1 en2 pa_en pab in1b in1a figure 1. block diagram
max8805y/MAX8805Z 600ma pwm step-down converters in 2mm x 2mm wlp for wcdma pa power ______________________________________________________________________________________ 13 detailed description the max8805y/MAX8805Z are designed to dynamical- ly power the pa in wcdma and ncdma handsets. the devices contain a high-frequency, high-efficiency step- down converter, and two ldos. the step-down convert- er delivers over 600ma. the hysteretic pwm control scheme provides extremely fast transient response, while 2mhz and 4mhz switching-frequency options allow the trade-off between efficiency and the smallest external components. a 60m bypass fet connects the pa directly to the battery during high-power trans- mission. step-down converter control scheme a hysteretic pwm control scheme ensures high effi- ciency, fast switching, fast transient response, low-out- put ripple, and physically tiny external components. the control scheme is simple: when the output voltage is below the regulation threshold, the error comparator begins a switching cycle by turning on the high-side switch. this high-side switch remains on until the mini- mum on-time expires and the output voltage is within regulation, or the inductor current is above the current- limit threshold. once off, the high-side switch remains off until the minimum off-time expires and the output voltage falls again below the regulation threshold. during the off period, the low-side synchronous rectifier turns on and remains on until the high-side switch turns on again. the internal synchronous rectifier eliminates the need for an external schottky diode. voltage-positioning load regulation the max8805y/MAX8805Z step-down converters utilize a unique feedback network. by taking dc feedback from the lx node through r1 in figure 1, the usual phase lag due to the output capacitor is removed, mak- ing the loop exceedingly stable and allowing the use of very small ceramic output capacitors. to improve the load regulation, resistor r3 is included in the feedback. this configuration yields load regulation equal to half of the inductor? series resistance multiplied by the load current. this voltage-positioning load regulation greatly reduces overshoot during load transients or when changing the output voltage from one level to another. however, when calculating the required refin voltage, the load regulation should be considered. because inductor resistance is typically well specified and the typical pa is a resistive load, the max8805y/MAX8805Z v refin to v out gain is slightly less than 2v/v. step-down converter bypass mode during high-power transmission, the bypass mode con- nects in1a and in1b directly to paa and pab with the internal 60m (typ) bypass fet, while the step-down converter is forced into 100% duty-cycle operation. the low on-resistance in this mode provides low dropout, long battery life, and high output current capability. forced and automatic bypass mode invoke forced bypass mode by driving hp high or invoke automatic bypass mode by applying a high volt- age to refin. to prevent excessive output ripple as the step-down converter approaches dropout, the max8805y/MAX8805Z enter bypass mode automatically when v refin > 0.465 x v in2 (see figure 2). note that in2 is used instead of in1 to prevent switching noise from causing false enagement of automatic bypass mode. for this reason, in2 must be connected to the same source as in1. shutdown mode connect pa_en to gnd or logic-low to place the max8805y/MAX8805Z pa step-down converter in shut- down mode. in shutdown, the control circuitry, internal switching mosfet, and synchronous rectifier turn off and lx becomes high impedance. connect pa_en to in1_ or logic-high for normal operation. connect en1 or en2 to gnd or logic-low to place ldo1 or ldo2, respectively, in shutdown mode. in shutdown, the outputs of the ldos are pulled to ground through an internal 1k resistor. when the pa step-down and ldos are all in shutdown, the max8805y/MAX8805Z enter a very low power state, where the input current drops to 0.1? (typ). 0 1.0 0.5 2.0 1.5 3.0 2.5 3.5 4.5 4.0 5.0 0101520 525303545 40 50 time (ms) in2 and pa_ voltage (v) refin voltage (v) in2 pa_ refin 0 0.5 1.0 1.5 2.0 2.5 figure 2. v in2 and v pa_ with automatic entry/exit into bypass mode
max8805y/MAX8805Z 600ma pwm step-down converters in 2mm x 2mm wlp for wcdma pa power 14 ______________________________________________________________________________________ step-down converter soft-start the max8805y/MAX8805Z pa step-down converter has internal soft-start circuitry that limits inrush current at startup, reducing transients on the input source. soft- start is particularly useful for supplies with high output impedance such as li+ and alkaline cells. see the soft- start waveforms in the typical operating characteristics. analog refin control the max8805y/MAX8805Z pa step-down converter uses refin to set the output voltage. the output voltage is reg- ulated at twice the voltage applied at refin minus the load regulation. this allows the converter to operate in applications where dynamic voltage control is required. thermal shutdown thermal shutdown limits total power dissipation in the max8805y/MAX8805Z. if the junction temperature exceeds +160?, thermal-shutdown circuitry turns off the ic, allowing it to cool. the ic turns on and begins soft-start after the junction temperature cools by 20?. this results in a pulsed output during continuous ther- mal-overload conditions. applications information output voltages the max8805y/MAX8805Z pa step-down converters set the pa_ output voltage to twice the voltage applied to refin. ldo1 and ldo2 output voltages are determined by the part number suffix, as shown in table 1. ldo dropout voltage the regulator? minimum input/output differential (or dropout voltage) determines the lowest usable supply voltage. in battery-powered systems, this determines the useful end-of-life battery voltage. because the max8805y/MAX8805Z ldos use a p-channel mosfet pass transistor, their dropout voltages are a function of drain-to-source on-resistance (r ds (on)) multiplied by the load current (see the typical operating characteristics ). inductor selection the max8805y operates with a switching frequency of 2mhz and utilizes a 2.2? inductor. the MAX8805Z operates with a switching frequency of 4mhz and uti- lizes a 1? inductor. the higher switching frequency of the MAX8805Z allows the use of physically smaller inductors at the cost of slightly lower efficiency. the lower switching frequency of the max8805y results in greater efficiency at the cost of a physically larger inductor. see the typical operating characteristics for efficiency graphs for both the max8805y and MAX8805Z. the inductor? dc current rating only needs to match the maximum load of the application because the max8805y/MAX8805Z feature zero current overshoot during startup and load transients. for optimum transient response and high efficiency, choose an inductor with dc series resistance in the 50m to 150m range. see table 2 for suggested inductors and manufacturers. output capacitor selection for the pa step-down converter, the output capacitor (c pa ) is required to keep the output voltage ripple small and ensure regulation loop stability. c pa must have low impedance at the switching frequency. ceramic capaci- tors with x5r or x7r dielectric are highly recommended due to their small size, low esr, and small temperature coefficients. due to the unique feedback network, the output capacitance can be very low. a 2.2? capacitor is recommended for most applications. for optimum load-transient performance and very low output ripple, the output capacitor value can be increased. for ldo1 and ldo2, the minimum output capacitance required is dependent on the load currents. for loads less than 10ma, it is sufficient to use a 0.1? capacitor for stable operation over the full temperature range. with rated maximum load currents, a minimum of 1? is recommended. reduce output noise and improve load- transient response, stability, and power-supply rejec- tion by using larger output capacitors. note that some ceramic dielectrics exhibit large capaci- tance and esr variation with temperature. with dielectrics such as z5u and y5v, it is necessary to use 2.2? or larg- er to ensure stability at temperatures below -10?. with x7r or x5r dielectrics, 1? is sufficient at all operating temperatures. these regulators are optimized for ceramic capacitors. tantalum capacitors are not recommended. table 1. ldo1 and ldo2 output voltage selection note: contact the factory for other output-voltage options. part frequency (mhz) ldo1 (v) ldo2 (v) max8805yeweaa+t 2 1.80 1.80 max8805yeweae+t 2 1.80 2.85 max8805yeweee+t 2 2.85 2.85 MAX8805Zeweaa+t 4 1.80 1.80 MAX8805Zeweae+t 4 1.80 2.85 MAX8805Zeweee+t 4 2.85 2.85
max8805y/MAX8805Z 600ma pwm step-down converters in 2mm x 2mm wlp for wcdma pa power ______________________________________________________________________________________ 15 input capacitor selection the input capacitor (c in1 ) of the pa converter reduces the current peaks drawn from the battery or input power source and reduces switching noise in the max8805y/MAX8805Z. the impedance of c in1 at the switching frequency should be kept very low. ceramic capacitors with x5r or x7r dielectric are highly recom- mended due to their small size, low esr, and small temperature coefficients. a 2.2? capacitor is recom- mended for most applications. for optimum noise immunity and low input ripple, the input capacitor value can be increased. for the ldos, use an input capacitance equal to the value of the sum of the output capacitance of ldo1 and ldo2. larger input capacitor values and lower esr pro- vide better noise rejection and line transient response. note that some ceramic dielectrics exhibit large capaci- tance and esr variation with temperature. with dielectrics such as z5u and y5v, it may be necessary to use two times the sum of the output capacitor values of ldo1 and ldo2 (or larger) to ensure stability at temper- atures below -10?. with x7r or x5r dielectrics, a capacitance equal to the sum is sufficient at all operating temperatures. table 2. suggested inductors manufacturer series inductance (?) esr ( ) current rating (ma) dimensions (mm) coilcraft lpo3310 1.0 1.5 2.2 0.07 0.10 0.13 1600 1400 1100 3.3 x 3.3 x 1.0 = 11mm 3 mipf2520 1.0 1.5 2.2 0.05 0.07 0.08 1500 1500 1300 2.5 x 2.0 x 1.0 = 5mm 3 mips2520 1.3 2.0 0.09 0.11 1500 1200 2.5 x 2.0 x 1.0 = 5mm 3 fdk mipf2016 1.0 2.2 0.11 1100 2.0 x 1.6 x 1.0 = 3.2mm 3 hitachi ksli-252010 1.5 2.2 0.115 0.080 2.5 x 2.0 x 1.0 = 5mm 3 murata lqh32c_53 1.0 2.2 0.06 0.10 1000 790 3.2 x 2.5 x 1.7 = 14mm 3 sumida cdrh2d09 1.2 1.5 2.2 0.08 0.09 0.12 590 520 440 3.0 x 3.0 x 1.0 = 9mm 3 cdrh2d11 1.5 2.2 3.3 0.05 0.08 0.10 680 580 450 3.2 x 3.2 x 1.2 = 12mm 3 taiyo yuden cb2518t 2.2 4.7 0.09 0.13 510 340 2.5 x 1.8 x 2.0 = 9mm 3 d3010fb 1.0 0.20 1170 3.0 x 3.0 x 1.0 = 9mm 3 d2812c 1.2 2.2 0.09 0.15 860 640 3.0 x 3.0 x 1.2 = 11mm 3 d310f 1.5 2.2 0.13 0.17 1230 1080 3.6 x 3.6 x 1.0 = 13mm 3 toko d312c 1.5 2.2 0.10 0.12 1290 1140 3.6 x 3.6 x 1.2 = 16mm 3
max8805y/MAX8805Z 600ma pwm step-down converters in 2mm x 2mm wlp for wcdma pa power 16 ______________________________________________________________________________________ thermal considerations in most applications, the max8805y/MAX8805Z do not dissipate much heat due to their high efficiency. however, in applications where the max8805y/ MAX8805Z run at high ambient temperature with heavy loads, the heat dissipated may exceed the maximum junction temperature of the ic. if the junction tempera- ture reaches approximately +160?, all power switches are turned off and lx and pa_ become high imped- ance, and ldo1 and ldo2 are pulled down to ground through an internal 1k pulldown resistor. the max8805y/MAX8805Z maximum power dissipation depends on the thermal resistance of the ic package and circuit board, the temperature difference between the die junction and ambient air, and the rate of airflow. the power dissipated in the device is: p diss = p pa x (1/ pa - 1) + i ldo1 x (v in2 - v ldo1 ) + i ldo2 x (v in2 -v ldo2 ) where pa is the efficiency of the pa step-down con- verter and p pa is the output power of the pa step-down converter. the maximum allowed power dissipation is: p max = (t jmax - t a ) / ja where (t jmax - t a ) is the temperature difference between the max8805y/MAX8805Z die junction and the surrounding air; ja is the thermal resistance of the junction through the pcb, copper traces, and other materials to the surrounding air. pcb layout high switching frequencies and relatively large peak currents make the pcb layout a very important part of design. good design minimizes excessive emi on the feedback paths and voltage gradients in the ground plane, resulting in a stable and well-regulated output. connect c in1 close to in1a/in1b and pgnd. connect the inductor and output capacitor as close as possible to the ic and keep their traces short, direct, and wide. keep noisy traces, such as the lx node, as short as possible. figure 3 illustrates an example pcb layout and routing scheme.
max8805y/MAX8805Z 600ma pwm step-down converters in 2mm x 2mm wlp for wcdma pa power ______________________________________________________________________________________ 17 refin vin pa_en en1 ldo1 ldo2 hp 5.5mm en2 agnd pgnd 3.8mm c in2 c pa c byp c ldo2 c ldo1 vpa l pa c in1 figure 3. recommended pcb layout
max8805y/MAX8805Z 600ma pwm step-down converters in 2mm x 2mm wlp for wcdma pa power 18 ______________________________________________________________________________________ 2.2 f 2mhz or 4mhz buck 1 h or 2.2 h* lx pbb pgnd pba in1a in1b en2 refin 2.2 f ref 0.22 f refbp agnd ldo1 0.1 f 0.1 f ldo2 in2 1 f pa_en hp en1 control en/bias in pa2 en/bias in pa1 gpio gpio gpio gpio dac baseband processor li+ battery ldo1 ldo2 max8805y/MAX8805Z *1 h fdk mips 2520d1r0 2.2 h fdk mipf 2520d2r2 figure 4. typical application circuit using ldos for pa enable/bias
max8805y/MAX8805Z 600ma pwm step-down converters in 2mm x 2mm wlp for wcdma pa power ______________________________________________________________________________________ 19 2.2 f 2mhz or 4mhz buck 1 h or 2.2 h* lx pbb pgnd pba in1a in1b en2 refin 2.2 f ref 0.22 f refbp agnd ldo1 1 f 1 f ldo2 in2 2.2 f pa_en hp en1 control rf transmitter in in pa gpio gpio gpio gpio dac baseband processor li+ battery ldo1 ldo2 max8805y/MAX8805Z rf receiver in *1 h fdk mips 2520d1r0 2.2 h fdk mipf 2520d2r2 figure 5. typical application circuit using ldos for rf power
max8805y/MAX8805Z 600ma pwm step-down converters in 2mm x 2mm wlp for wcdma pa power 20 ______________________________________________________________________________________ refbp agnd ldo2 in2 refin en2 in1b pa_en (bump in bottom) 16-bump, 2mm 2mm wlp hp ldo1 pab en1 pgnd lx in1a paa a1 a2 a3 a4 b1 b4 b3 b2 c1 c2 c3 c4 d1 d4 d3 d2 top view pin configuration chip information process: bicmos
max8805y/MAX8805Z 600ma pwm step-down converters in 2mm x 2mm wlp for wcdma pa power 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. maxim integrated products, 120 san gabriel drive, sunnyvale, ca 94086 408-737-7600 ____________________ 21 2007 maxim integrated products is a registered trademark of maxim integrated products, inc. 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 .) 16l wlp.eps

▲Up To Search▲

Price & Availability of MAX8805Z

	To Download MAX8805Z Datasheet File
If you can't view the Datasheet, Please click here to try to view without PDF Reader .