View LT1679ISPBF_6867187.PDF datasheet online --- IC-ON-LINE

Datasheet File OCR Text:

lt1678/lt1679 1 sn16789 16789fs features applicatio s u descriptio u typical applicatio u dual/quad low noise, rail-to-rail, precision op amps rail-to-rail input and output 100% tested low voltage noise: 3.9nv/ hz typ at 1khz 5.5nv/ hz max at 1khz single supply operation from 2.7v to 36v offset voltage: 100 v max low input bias current: 20na max high a vol : 3v/ v min, r l = 10k high cmrr: 100db min high psrr: 106db min gain bandwidth product: 20mhz operating temperature range: 40 c to 85 c matching specifications no phase inversion 8-lead so and 14-lead so packages the lt 1678/lt1679 are dual/quad rail-to-rail op amps offering both low noise and precision: 3.9nv/ hz wideband noise, 1/f corner frequency of 4hz and 90nv peak-to-peak 0.1hz to 10hz noise are combined with outstanding precision: 100 v maximum offset voltage, greater than 100db common mode and power supply rejection and 20mhz gain bandwidth product. the lt1678/lt1679 bring precision as well as low noise to single supply applications as low as 3v. the input range exceeds the power supply by 100mv with no phase inversion while the output can swing to within 170mv of either rail. the lt1678/lt1679 are offered in the so-8 and so-14 packages. a full set of matching specifications are also provided, facilitating their use in matching dependent appli- cations such as a two op amp instrumentation amplifier design. the lt1678/lt1679 are specified for supply volt- ages of 15v, single 5v as well as single 3v. for a single amplifier with similiar performance, see the lt1677 data sheet. instrumentation amplifier with shield driver strain gauge amplifiers portable microphones battery-powered rail-to-rail instrumentation low noise signal processing microvolt accuracy threshold detection infrared detectors , ltc and lt are registered trademarks of linear technology corporation. 0.1hz to 10hz voltage noise + 1/4 lt1679 16789 ta01 + + 1/4 lt1679 1/4 lt1679 15v 15v output 1/4 lt1679 30k 1k r f 3.4k r g 100 ? r f 3.4k 30k 1k 5 4 6 11 7 1 3 2 10 9 8 14 13 12 + input guard guard r g 100 ? + gain = 1000 time (sec) voltage noise (50nv/div) 16789 ta01b v s = 2.5v 46810 02
lt1678/lt1679 2 sn16789 16789fs symbol parameter conditions (note 6) min typ max units v os input offset voltage (note 11) 35 100 v 0 c t a 70 c 55 270 v ?0 c t a 85 c 75 350 v v s =5v, v cm = v s + 0.1v 150 550 v v s =5v, v cm = v s ?0.3v, 0 c t a 70 c 180 750 v v s =5v, v cm = v s ?0.3v, 40 c t a 85 c 200 1000 v v s =5v, v cm = 0.1v 1.5 30 mv v s =5v, v cm = 0v, 0 c t a 70 c 1.8 45 mv v s =5v, v cm = 0v, 40 c t a 85 c 2.0 50 mv ? v os average input offset drift (note 10) 0.40 3 v/ c ? temp i b input bias current (note 11) 2 20 na 0 c t a 70 c 3 35 na ?0 c t a 85 c 7 50 na v s = 5v, v cm = v s + 0.1v 0.19 0.40 a v s = 5v, v cm = v s ?0.3v, 0 c t a 70 c 0.19 0.60 a v s = 5v, v cm = v s ?0.3v, 40 c t a 85 c 0.25 0.75 a v s = 5v, v cm = 0.1v 5 0.41 a v s = 5v, v cm = 0v, 0 c t a 70 c 8.4 0.45 a v s = 5v, v cm = 0v, 40 c t a 85 c ?0 0.47 a the denotes the specifications which apply over the full operating temperature range, otherwise specifications are at t a = 25 c. v s = 3v, v cm = v o = 1.7v; v s = 5v, v cm = v o = 2.5v unless otherwise noted. electrical characteristics (note 1) supply voltage ...................................................... 18v input voltages (note 2) ............ 0.3v beyond either rail differential input current (note 2) ..................... 25ma output short-circuit duration (note 3) ............ indefinite storage temperature range ................. 65 c to 150 c order part number lt1678cs8 lt1678is8 s8 part marking 1678 1678i t jmax = 150 c, ja = 190 c/ w absolute axi u rati gs w ww u package/order i for atio uu w consult ltc marketing for parts specified with wider operating temperature ranges. lead temperature (soldering, 10 sec.)................. 300 c operating temperature range (note 4) ............................................. 40 c to 85 c specified temperature range (note 5) ............................................. 40 c to 85 c order part number lt1679cs lt1679is top view s package 14-lead plastic so 1 2 3 4 5 6 7 14 13 12 11 10 9 8 out a ?n a +in a v + +in b ?n b out b out d ?n d +in d v +in c ?n c out c ad c b t jmax = 150 c, ja = 160 c/ w top view s8 package 8-lead plastic so 1 2 3 4 8 7 6 5 out a v + out b in b +in b in a +in a v a b
lt1678/lt1679 3 sn16789 16789fs symbol parameter conditions (note 6) min typ max units i os input offset current (note 11) 4 25 na 0 c t a 70 c 535 na ?0 c t a 85 c 855 na v s = 5v, v cm = v s + 0.1v 6 30 na v s = 5v, v cm = v s ?0.3v, 0 c t a 70 c 10 40 na v s = 5v, v cm = v s ?0.3v, 40 c t a 85 c 15 65 na v s = 5v, v cm = 0.1v 0.1 1.6 a v s = 5v, v cm = 0v, 0 c t a 70 c 0.1 2.0 a v s = 5v, v cm = 0v, 40 c t a 85 c 0.15 2.4 a e n input noise voltage 0.1hz to 10hz (note 7) 90 nv p-p v cm = v s 180 nv p-p v cm = 0v 1600 nv p-p input noise voltage density (note 8) f o = 10hz 4.4 nv/ hz v cm = v s , f o = 10hz 6.6 nv/ hz v cm = 0v, f o = 10hz 19 nv/ hz f o = 1khz 3.9 5.5 nv/ hz v cm = v s , f o = 1khz 5.3 nv/ hz v cm = 0v, f o = 1khz 9 nv/ hz i n input noise current density f o = 10hz 1.2 pa/ hz f o = 1khz 0.3 pa/ hz v cm input voltage range 0.1 v s + 0.1v v 0v s ?0.3v v r in input resistance common mode 2 g ? c in input capacitance 4.2 pf cmrr common mode rejection ratio v s = 5v, v cm = 1.9v to 3.9v 98 120 db v s = 5v, v cm = 1.9v to 3.9v 92 120 db psrr power supply rejection ratio v s = 2.7v to 36v, v cm = v o = 1.7v 100 125 db v s = 3.1v to 36v, v cm = v o = 1.7v 98 120 db a vol large-signal voltage gain v s = 3v, r l = 10k, v o = 2.5v to 0.7v 0.6 3 v/ v 0.3 2 v/ v v s = 3v, r l = 2k, v o = 2.2v to 0.7v 0.5 3 v/ v 0 c t a 70 c 0.4 0.9 v/ v ?0 c t a 85 c 0.4 0.8 v/ v v s = 3v, r l = 600 ? , v o = 2.2v to 0.7v 0.20 0.43 v/ v 0 c t a 70 c 0.15 0.40 v/ v ?0 c t a 85 c 0.10 0.35 v/ v v s = 5v, r l = 10k, v o = 4.5v to 0.7v 1 3.8 v/ v o c < t a < 70 c 0.6 2 v/ v ?0 < t a < 85 c 0.3 2 v/ v v s = 5v, r l = 2k, v o = 4.2v to 0.7v 0.7 3.5 v/ v 0 c t a 70 c 0.6 3.2 v/ v ?0 c t a 85 c 0.5 3.0 v/ v v s = 5v, r l = 600 ? , v o = 4.2v to 0.7v 0.6 3.0 v/ v 0 c t a 70 c 0.5 2.8 v/ v ?0 c t a 85 c 0.4 2.5 v/ v v ol output voltage swing low (note 11) above gnd i sink = 0.1ma 80 170 mv 0 c t a 70 c 125 200 mv 40 c t a 85 c 130 250 mv the denotes the specifications which apply over the full operating temperature range, otherwise specifications are at t a = 25 c. v s = 3v, v cm = v o = 1.7v; v s = 5v, v cm = v o = 2.5v unless otherwise noted. electrical characteristics
lt1678/lt1679 4 sn16789 16789fs symbol parameter conditions (note 6) min typ max units v ol output voltage swing low (note 11) above gnd i sink = 2.5ma 170 250 mv 0 c t a 70 c 195 320 mv 40 c t a 85 c 205 350 mv above gnd i sink = 10ma 370 600 mv 0 c t a 70 c 440 720 mv 40 c t a 85 c 465 770 mv v oh output voltage swing high (note 11) below v s i source = 0.1ma 75 150 mv 0 c t a 70 c 85 200 mv 40 c t a 85 c 93 250 mv below v s i source = 2.5ma 110 250 mv 0 c t a 70 c 195 350 mv 40 c t a 85 c 205 375 mv below v s i source = 10ma 170 400 mv 0 c t a 70 c 200 500 mv 40 c t a 85 c 230 550 mv i sc output short-circuit current (note 3) v s = 3v 15 22 ma 13 19 ma v s = 5v 18 29 ma 14 25 ma sr slew rate (note 13) a v = 1, r l = 10k 4 6 v/ s r l = 10k, 0 c t a 70 c 3.5 5.8 v/ s r l = 10k, 40 c t a 85 c 3 5.5 v/ s gbw gain bandwidth product (note 11) f o = 100khz 13 20 mhz f o = 100khz 12.5 19 mhz t s settling time 2v step 0.1%, a v = +1 1.4 s 2v step 0.01%, a v = +1 2.4 s r o open-loop output resistance i out = 0 100 ? closed-loop output resistance a v = 100, f = 10khz 1 ? i s supply current per amplifier (note 12) 2 3.4 ma 2.5 3.8 ma ? v os offset voltage match 35 150 v (notes 11, 15) 0 c t a 70 c 55 400 v ?0 c t a 85 c 75 525 v ? ib+ noninverting bias current match 2 30 na (notes 11, 15) 0 c t a 70 c 3 55 na ?0 c t a 85 c 7 75 na ? cmrr common mode rejection match v s = 5v, v cm = 1.9v to 3.9v 94 110 db (notes 11, 14, 15) 88 110 db ? psrr power supply rejection match v s = 2.7v to 36v, v cm = v o = 1.7v 96 120 db (notes 11, 14, 15) v s = 3.1v to 36v, v cm = v o = 1.7v 94 120 db the denotes the specifications which apply over the full operating temperature range, otherwise specifications are at t a = 25 c. v s = 3v, v cm = v o = 1.7v; v s = 5v, v cm = v o = 2.5v unless otherwise noted. electrical characteristics
lt1678/lt1679 5 sn16789 16789fs electrical characteristics symbol parameter conditions (note 6) min typ max units v os input offset voltage 20 150 v 0 c t a 70 c 30 350 v ?0 c t a 85 c 45 420 v ? v os average input offset drift (note 10) 0.40 3 v/ c ? temp i b input bias current 2 20 na 0 c t a 70 c 3 35 na ?0 c t a 85 c 7 50 na i os input offset current 325 na 0 c t a 70 c 535 na ?0 c t a 85 c 855 na e n input noise voltage 0.1hz to 10hz (note 7) 90 nv p-p v cm = 15v 180 nv p-p v cm = 15v 1600 nv p-p input noise voltage density f o = 10hz 4.4 nv/ hz v cm = 15v, f o = 10hz 6.6 nv/ hz v cm = 15v, f o = 10hz 19 nv/ hz f o = 1khz 3.9 5.5 nv/ hz v cm = 15v, f o = 1khz 5.3 nv/ hz v cm = 15v, f o = 1khz 9 nv/ hz i n input noise current density f o = 10hz 1.2 pa/ hz f o = 1khz 0.3 pa/ hz v cm input voltage range (note 16) 13.3 14 v r in input resistance common mode 2 g ? c in input capacitance 4.2 pf cmrr common mode rejection ratio v cm = 13.3v to 14v 100 130 db 96 124 db psrr power supply rejection ratio v s = 1.7v to 18v 106 130 db 100 125 db a vol large-signal voltage gain r l = 10k, v o = 14v 3 7 v/ v 0 c t a 70 c 26 v/ v ?0 c t a 85 c 14 v/ v r l = 2k, v o = 13.5v 0.8 1.7 v/ v 0 c t a 70 c 0.5 1.4 v/ v ?0 c t a 85 c 0.4 1.1 v/ v the denotes the specifications which apply over the full operating temperature range, otherwise specifications are at t a = 25 c. v s = 15v, v cm = v o = 0v unless otherwise noted.
lt1678/lt1679 6 sn16789 16789fs symbol parameter conditions (note 6) min typ max units v ol output voltage swing low above v s i sink = 0.1ma 110 200 mv 0 c t a 70 c 125 230 mv 40 c t a 85 c 130 260 mv above v s i sink = 2.5ma 170 280 mv 0 c t a 70 c 195 350 mv 40 c t a 85 c 205 380 mv above v s i sink = 10ma 370 600 mv 0 c t a 70 c 440 700 mv 40 c t a 85 c 450 750 mv v oh output voltage swing high below +v s i source = 0.1ma 80 150 mv 0 c t a 70 c 90 200 mv 40 c t a 85 c 100 250 mv below +v s i source = 2.5ma 110 200 mv 0 c t a 70 c 120 300 mv 40 c t a 85 c 120 350 mv below +v s i source = 10ma 200 450 mv 0 c t a 70 c 250 500 mv 40 c t a 85 c 250 550 mv i sc output short-circuit current (note 3) 20 35 ma 15 28 ma sr slew rate r l = 10k (note 9) 4 6 v/ s r l = 10k (note 9) 0 c t a 70 c 3.5 5.8 v/ s r l = 10k (note 9) 40 c t a 85 c 3 5.5 v/ s gbw gain bandwidth product f o = 100khz 13 20 mhz f o = 100khz 12.5 19 mhz thd total harmonic distortion r l = 2k, a v = 1, f o = 1khz, v o = 20v p-p 0.00025 % t s settling time 10v step 0.1%, a v = +1 2.7 s 10v step 0.01%, a v = +1 3.9 s r o open-loop output resistance i out = 0 100 ? closed-loop output resistance a v = 100, f = 10khz 1 ? i s supply current per amplifier 2.5 3.5 ma 3 4.5 ma channel separation f = 10hz, v o = 10v, r l = 10k 132 db ? v os offset voltage match 5 225 v (note 15) 0 c t a 70 c 30 525 v ?0 c t a 85 c 45 630 v ? ib+ noninverting bias current match 2 30 na (note 15) 0 c t a 70 c 3 55 na ?0 c t a 85 c 7 75 na ? cmrr common mode rejection match v cm = 13.3v to 14v 96 120 db (notes 14, 15) 92 115 db ? psrr power supply rejection match v s = 1.7v to 18v 100 123 db (notes 14, 15) 96 120 db the denotes the specifications which apply over the full operating temperature range, otherwise specifications are at t a = 25 c. v s = 15v, v cm = v o = 0v unless otherwise noted. electrical characteristics
lt1678/lt1679 7 sn16789 16789fs note 1: absolute maximum ratings are those values beyond which the life of the device may be impaired. note 2: the inputs are protected by back-to-back diodes. current limiting resistors are not used in order to achieve low noise. if differential input voltage exceeds 1.4v, the input current should be limited to 25ma. if the common mode range exceeds either rail, the input current should be limited to 10ma. note 3: a heat sink may be required to keep the junction temperature below absolute maximum. note 4: the lt1678c/lt1679c and lt1678i/lt1679i are guaranteed functional over the operating temperature range of 40 c to 85 c. note 5: the lt1678c/lt1679c are guaranteed to meet specified performance from 0 c to 70 c. the lt1678c/lt1679c are designed, characterized and expected to meet specified performance from 40 c to 85 c but is not tested or qa sampled at these temperatures. the lt1678i/ lt1679i are guaranteed to meet specified performance from 40 c to 85 c. note 6: typical parameters are defined as the 60% yield of parameter distributions of individual amplifier; i.e., out of 100 lt1678/lt1679s, typically 60 op amps will be better than the indicated specification. note 7: see the test circuit and frequency response curve for 0.1hz to10hz tester in the applications information section. note 8: noise is 100% tested at 15v supplies. note 9: slew rate is measured in a v = 1; input signal is 10v, output measured at 5v. note 10: this parameter is not 100% tested. note 11: v s = 5v limits are guaranteed by correlation to v s = 3v and v s = 15v tests. note 12: v s = 3v limits are guaranteed by correlation to v s = 5v and v s = 15v tests. note 13: guaranteed by correlation to slew rate at v s = 15v and gbw at v s = 3v and v s = 15v tests. note 14: ? cmrr and ? psrr are defined as follows: 1. cmrr and psrr are measured in v/v on the individual amplifiers. 2. the difference is calculated between the matching sides in v/v. 3. the result is converted to db. note 15: matching parameters are the difference between amplifiers a and b on the lt1678 and between amplifiers a and d and b and c in the lt1679. note 16: input range guaranteed by the common mode rejection ratio test. electrical characteristics typical perfor a ce characteristics uw frequency (hz) 0.1 1 noise voltage (nv/ hz) 10 100 10 1000 16789 g01 1 100 16789 g02 voltage noise (50nv/div) 16789 g03 v s = 15v t a = 25 c v cm = 0v v cm = 14.5v v s = 5v, 0v time (sec) voltage noise (50nv/div) v s = 5v, 0v 46810 02 time (sec) 40 60 80 100 020 voltage noise vs frequency 0.1hz to 10hz voltage noise 0.01hz to 1hz voltage noise
lt1678/lt1679 8 sn16789 16789fs typical perfor a ce characteristics uw input bias current (na) 16 14 12 10 8 6 4 2 0 ? ? ? temperature ( c) ?0 25 75 16789 g06 ?5 0 50 100 125 input bias current (na) 900 700 500 300 100 ?00 ?00 ?00 ?00 ?00 16789 g08 common mode input voltage (v) ?6 16 ? 0 8 ?2 ? 4 12 v s = 15v v cm = 0v v cm = ?3.5v v cm = 14.5v v cm = ?5.2v v cm = 14.1v input bias current v s = 15v t a = 25 c time (min) 0 change in offset voltage ( v) 4 16789 g10 1 2 3 10 8 6 4 2 0 temperature ( c) ?5 voltage offset ( v) 200 100 0 ?00 ?00 ?00 ?5 25 45 125 16789 g12 ?5 5 65 85 105 v s = 15v t a = 25 c so package v s = 5v, 0v v cm = 0v temperature ( c) ?0 rms voltage noise density (nv/ hz) 6 5 4 3 2 1 0 50 75 16789 g04 ?5 25 100 125 temperature ( c) ?0 0 50 75 16789 g07 ?5 25 100 125 v s = 15v v cm = 0v 10hz 1khz frequency (khz) 0.01 0.1 noise voltage (pa/ hz) 1 10 0.1 1 10 16789 g05 v s = 15v t a = 25 c v cm = 0v v cm = 14.5v 1400 1200 1000 800 600 400 200 0 input bias current (na) v cm = ?4v current out of dut v cm = 14.7v current into dut v s = 15v v cm ?v + (v) v cm ?v (v) ?.0 offset voltage (mv) 5 4 3 2 1 0 ? ? ? ? ? 500 400 300 200 100 0 ?00 ?00 ?00 ?00 ?00 0.8 0.4 v + 0.4 16789 g09 v 1.0 2.0 v os is referred to v cm = 0v v s = 1.5v to 15v t a = 25 c 5 typical parts offset voltage ( v) input offset voltage drift ( v/ c) ?.0 3.0 percent of units (%) 30 25 20 15 10 5 0 0 16789 g11 ?.0 2.0 ?.0 1.0 v s = 5v, 0v t a = 40 c to 85 c 111 parts (2 lots) input bias current vs temperature input bias current over the common mode range warm-up drift vs time v os vs temperature of representive units distribution of input offset voltage drift (so-8) voltage noise vs temperature current noise vs frequency input bias current vs temperature offset voltage shift vs common mode
lt1678/lt1679 9 sn16789 16789fs supply voltage (v) 0 supply current per amplifier (ma) 4.0 3.5 3.0 2.5 2.0 1.5 1.0 5 10 15 20 16789 g14 frequency (hz) 10k common mode rejection ratio (db) 160 140 120 100 80 60 40 20 0 100k 1m 10m 16789 g15 frequency (khz) 0.001 0.01 power supply rejection ratio (db) 0.1 10 1 100 1000 16789 g16 160 140 120 100 80 60 40 20 0 capacitive load (pf) 10 0 overshoot (%) 10 20 30 40 60 100 1000 16789 g18 50 t a = 25 c t a = 125 c t a = ?5 c v s = 15v t a = 25 c v cm = 0v v s = 15v t a = 25 c negative supply positive supply rising edge falling edge v s = 15v r l = 2k to 10k a v = 1 t a = 25 c gain bandwidth product, f o = 100khz (mhz) 30 25 20 15 10 16789 g19 90 80 70 60 50 40 v s = 15v c l = 15pf a v = ? r f = r g = 1k gain bandwidth product phase margin phase margin (deg) temperature ( c) ?5 ?5 25 45 125 ?5 5 65 85 105 10v ?0v 5 s/div a vcl = ? v s = 15v 16789 g20 50mv ?0mv 0v 0.5 s/div a vcl = 1 v s = 15v c l = 15pf 16789 g21 slew rate (v/ s) +sr ?r 8 6 4 v cm ?v s + (v) v cm ?v s (v) ?.0 offset voltage (mv) 5 4 3 2 1 0 ? ? ? ? ? 500 400 300 200 100 0 ?00 ?00 ?00 ?00 ?00 0.8 0.4 v 0.4 16789 g09 v 1.0 2.0 v s = 2.5v to 15v offset voltage ( v) v os is referred to v cm = 0v 25 c 25 c 125 c 125 c ?5 c ?5 c supply voltage (v) 0.1 1 10 10 20 16789 g17 open loop voltage gain (v/ v) 0 30 t a = 25 c r l to gnd v cm = v o = v s /2 r l = 10k r l = 2k typical perfor a ce characteristics uw supply current vs supply voltage common mode rejection ratio vs frequency power supply rejection ratio vs frequency % overshoot vs capacitive load phase margin, gain bandwidth product and slew rate vs temperature large signal transient response small signal transient response common mode range vs temperature voltage gain vs supply voltage
lt1678/lt1679 10 sn16789 16789fs frequency (mhz) 0.1 voltage gain (db) 50 40 30 20 10 0 ?0 phase shift (deg) 100 80 60 40 20 0 ?0 phase shift (deg) 100 80 60 40 20 0 ?0 1 10 100 16789 g24 gain phase v s = 15v v cm = 0v c l = 10pf t a = ?5 c t a = 25 c t a = 125 c t a = 125 c t a = 25 c t a = ?5 c frequency (mhz) 0.1 voltage gain (db) 50 40 30 20 10 0 ?0 1 10 100 16789 g26 gain phase v s = 15v v cm = ?4v c l = 10pf frequency (mhz) 0.1 voltage gain (db) 50 40 30 20 10 0 ?0 1 10 100 16789 g25 gain phase v s = 15v v cm = 14.7v c l = 10pf t a = 125 c t a = ?5 c phase shift (deg) 100 80 60 40 20 0 ?0 t a = 25 c t a = 125 c t a = ?5 c t a = 25 c t a = 25 c t a = ?5 c t a = ?5 c t a = 125 c t a = 25 c frequency (hz) 10 output impedance ( ? ) 100 10 1 0.1 0.01 0.001 100k 16789 g28 100 1k 10k 1m a v = 1 a v = 100 v s = 15v output step (v) ?0 ? ? 0 4 8 settling time ( s) 6 5 4 3 2 1 0 ? ? 2 6 16789 g22 settling time ( s) 6 5 4 3 2 1 0 10 output step (v) ?0 ? ? 0 4 8 ? ? 2 6 10 16789 g23 + 5k 5k v in v out + 2k 2k v in v out r l = 1k v s = 15v a v = 1 t a = 25 c v s = 15v a v = ? t a = 25 c 0.1% of full scale 0.1% of full scale 0.1% of full scale 0.1% of full scale 0.01% of full scale 0.01% of full scale 0.01% of full scale 0.01% of full scale output current (ma) ?0 output voltage swing (v) ? ? 0810 16789 g27 ? 4 2 4 6 0 ?.1 ?.2 ?.3 0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.1 0 v s = 15v t a = 125 c t a = 125 c t a = 25 c t a = ?5 c t a = ?5 c t a = 25 c frequency (hz) total harmonic distortion + noise (%) 20 1k 10k 50k 16789 g29 100 0.1 0.01 0.001 0.0001 frequency (hz) total harmonic distortion + noise (%) 20 1k 10k 50k 16789 g30 100 0.1 0.01 0.001 0.0001 a v = 100 a v = 10 a v = 1 a v = ?00 a v = ?0 a v = ? z l = 2k/15pf v s = 15v v o = 20v p-p a v = 1, 10, 100 measurement bandwidth = 10hz to 80khz z l = 2k/15pf v s = 15v v o = 20v p-p a v = ?, ?0, ?00 measurement bandwidth = 10hz to 80khz +v s ? s typical perfor a ce characteristics uw gain, phase shift vs frequency gain, phase shift vs frequency gain, phase shift vs frequency closed-loop output impedance vs frequency settling time vs output step (inverting) settling time vs output step (noninverting) output voltage swing vs load current total harmonic distortion and noise vs frequency for noninverting gain total harmonic distortion and noise vs frequency for noninverting gain
lt1678/lt1679 11 sn16789 16789fs rail-to-rail operation to take full advantage of an input range that can exceed the supply, the lt1678/lt1679 are designed to eliminate phase reversal. referring to the photographs shown in figure 1, the lt1678/lt1679 are operating in the fol- lower mode (a v = +1) at a single 3v supply. the output of the lt1678/lt1679 clips cleanly and recovers with no phase reversal. this has the benefit of preventing lock-up in servo systems and minimizing distortion components. input and a current, limited only by the output short-circuit protection, will be drawn by the signal generator. with r f 500 ? , the output is capable of handling the current requirements (i l 20ma at 10v) and the amplifier stays in its active mode and a smooth transition will occur. as with all operational amplifiers when r f > 2k, a pole will be created with r f and the amplifier? input capacitance, creating additional phase shift and reducing the phase margin. a small capacitor (20pf to 50pf) in parallel with r f will eliminate this problem. applicatio s i for atio wu uu figure 1. voltage follower with input exceeding the supply voltage (v s = 3v) input = ?.5v to 3.5v lt1678 output figure 2. pulsed operation noise testing the 0.1hz to 10hz peak-to-peak noise of the lt1678/ lt1679 are measured in the test circuit shown (figure 3). the frequency response of this noise tester (figure 4) indicates that the 0.1hz corner is defined by only one zero. the test time to measure 0.1hz to 10hz noise should not exceed ten seconds, as this time limit acts as an additional zero to eliminate noise contributions from the frequency band below 0.1hz. measuring the typical 90nv peak-to-peak noise perfor- mance of the lt1678/lt1679 requires special test pre- cautions: 1. the device should be warmed up for at least five minutes. as the op amp warms up, its offset voltage changes typically 3 v due to its chip temperature increasing 10 c to 20 c from the moment the power supplies are turned on. in the ten-second measurement interval these temperature-induced effects can easily exceed tens of nanovolts. 2. for similar reasons, the device must be well shielded from air currents to eliminate the possibility of thermoelectric effects in excess of a few nanovolts, which would invalidate the measurements. 16789 f01a 3 2 1 0.5 0 input voltage (v) 50 s/div 16789 f01b 3 2 1 0.5 0 output voltage (v) 50 s/div 16789 f02 lt1678 + r f output 6v/ s unity-gain buffer application when r f 100 ? and the input is driven with a fast, large- signal pulse (>1v), the output waveform will look as shown in the pulsed operation diagram (figure 2). during the fast feedthrough-like portion of the output, the input protection diodes effectively short the output to the
lt1678/lt1679 12 sn16789 16789fs 3. sudden motion in the vicinity of the device can also ?eedthrough?to increase the observed noise. current noise is measured in the circuit shown in figure 5 and calculated by the following formula: i e nv m n no = () ? () ? ? ? ? ? ? ()() 2 2 12 130 101 1 101 ? / ? the lt1678/lt1679 achieve their low noise, in part, by operating the input stage at 100 a versus the typical 10 a of most other op amps. voltage noise is inversely propor- tional while current noise is directly proportional to the square root of the input stage current. therefore, the lt1678/lt1679 ? current noise will be relatively high. at low frequencies, the low 1/f current noise corner fre- quency ( 200hz) minimizes current noise to some extent. in most practical applications, however, current noise will not limit system performance. this is illustrated in the total noise vs source resistance plot (figure 6) where: applicatio s i for atio wu uu 16789 f03 10 ? 0.1 f 4.7 f voltage gain = 50,000 24.3k 100k + + * lt1678 lt1001 2k 4.3k 110k 100k scope 1 r in = 1m *device under test note: all capacitor values are for nonpolarized capacitors only 2.2 f 0.1 f 22 f frequency (hz) 100 90 80 70 60 50 40 30 0.01 1 10 100 16789 f04 0.1 gain (db) 16789 f05 100 ? 100k + lt1678 500k 500k e no figure 3. 0.1hz to 10hz noise test circuit figure 4. 0.1hz to 10hz peak-to-peak noise tester frequency response figure 5. total noise = [(op amp voltage noise) 2 + (resistor noise) 2 + (current noise r s ) 2 ] 1/2 three regions can be identified as a function of source resistance: (i) r s 400 ? . voltage noise dominates (ii) 400 ? r s 50k at 1khz 400 ? r s 8k at 10hz (iii) r s > 50k at 1khz r s > 8k at 10hz resistor noise dominates current noise dominates clearly the lt1678/lt1679 should not be used in region (iii), where total system noise is at least six times higher than the voltage noise of the op amp, i.e., the low voltage noise specification is completely wasted. in this region the lt1113 or lt1169 are better choices. source resistance (k ? ) 0.1 1 10 100 1000 1 10 100 16789 f06 total noise density (nv/ hz) v s = 15v t a = 25 c source resistance = 2r r r at 1khz at 10hz resistor noise only figure 6. total noise vs source resistance
lt1678/lt1679 13 sn16789 16789fs rail-to-rail input the input common mode range for the lt1678/lt1679 can exceed the supplies by at least 100mv. as the common mode voltage approaches the positive rail (+v s ?0.7v), the tail current for the input pair (q1, q2) is reduced, which prevents the input pair from saturating (refer to the simplified schematic). the voltage drop across the load resistors r c1 , r c2 is reduced to less than 200mv, degrading the slew rate, bandwidth, voltage noise, offset voltage and input bias current (the cancella- tion is shut off). when the input common mode range goes below 1.5v above the negative rail, the npn input pair (q1, q2) shuts off and the pnp input pair (q8, q9) turns on. the offset voltage, input bias current, voltage noise and bandwidth are also degraded. the graph of offset voltage shift vs common mode shows where the knees occur by display- ing the change in offset voltage. the change-over points are temperature dependent; see the graph common mode range vs temperature. rail-to-rail output the rail-to-rail output swing is achieved by using transis- tor collectors (q28, q29 referring to the simplified sche- matic) instead of customary class a-b emitter followers for the output stage. the output npn transistor (q29) sinks the current necessary to move the output in the negative direc- tion. the change in q29? base emitter voltage is reflected directly to the gain node (collectors of q20 and q16). for large sinking currents, the delta v be of q29 can dominate the gain. figure 7 shows the change in input voltage for a change in output voltage for different load resistors con- nected between the supplies. the gain is much higher for output voltages above ground (q28 sources current) since the change in base emitter voltage of q28 is attenuated by the gain in the pnp portion of the output stage. therefore, for positive output swings (output sourcing current) there is hardly any change in input voltage for any load resistance. highest gain and best linearity are achieved when the output is sourcing current, which is the case in single supply op- eration when the load is ground referenced. figure 8 shows gains for both sinking and sourcing load currents for a worst-case load of 600 ? . ?5 ?0 ? 0 5 10 15 output voltage (v) input voltage (50 v/div) r l = 10k r l = 600 ? r l = 1k 16789 f07 t a = 25 c v s = 15v r l connected to 0v measured on tektronix 577 curve tracer 12 035 4 output voltage (v) input voltage (10 v/div) r l to 5v r l to 0v 16789 f08 voltage gain single supply v s = 5v r l = 600 ? measured on tektronix 577 curve tracer figure 7. voltage gain split supply figure 8. voltage gain single supply applicatio s i for atio wu uu
lt1678/lt1679 14 sn16789 16789fs si plified sche atic ww r8 200 ? r21 100 ? r13 100 ? r24 100 ? r9 200 ? q1a q10 q12 q5 q6 q4 q7 c10 81pf r c2 6k r c1 6k q11 q3 ib d4 d3 d1 d2 ic id 50 a ia, ib = 0 a v cm > 1.5v above v s 200 a v cm < 1.5v above v s ic = 200 a v cm < 0.7v below +v s 50 a v cm > 0.7v below +v s id = 100 a v cm < 0.7v below +v s 0 a v cm > 0.7v below +v s ia q8 q9 q21 q13 2 q2b q17 q18 r15 1k q24 + +in ?n 50 a q15 q14 q16 q25 q22 100 a r14 1k r16 1k r25 1k r30 2k r26 100 ? r29 10 ? r23b 10k r23a 10k 100 a 160 a q19 q20 r20 2k r2 50 ? r19 2k 200 a q38 q23 c2 80pf + r32 1.5k q32 r34 2k r54 100 ? r3 100 ? c3 40pf c4 20pf q29 16789 ss q26 q30 q31 + r1 500 ? c1 40pf + + q27 q35 q34 q28 out ? s +v s q1b q2a
lt1678/lt1679 15 sn16789 16789fs u package descriptio .016 ?.050 (0.406 ?1.270) .010 ?.020 (0.254 ?0.508) 45 0 ?8 typ .008 ?.010 (0.203 ?0.254) so8 0303 .053 ?.069 (1.346 ?1.752) .014 ?.019 (0.355 ?0.483) typ .004 ?.010 (0.101 ?0.254) .050 (1.270) bsc 1 2 3 4 .150 ?.157 (3.810 ?3.988) note 3 8 7 6 5 .189 ?.197 (4.801 ?5.004) note 3 .228 ?.244 (5.791 ?6.197) .245 min .160 .005 recommended solder pad layout .045 .005 .050 bsc .030 .005 typ inches (millimeters) note: 1. dimensions in 2. drawing not to scale 3. these dimensions do not include mold flash or protrusions. mold flash or protrusions shall not exceed .006" (0.15mm) s8 package 8-lead plastic small outline (narrow .150 inch) (reference ltc dwg # 05-08-1610) s package 14-lead plastic small outline (narrow .150 inch) (reference ltc dwg # 05-08-1610) 1 n 2 3 4 .150 ?.157 (3.810 ?3.988) note 3 14 13 .337 ?.344 (8.560 ?8.738) note 3 .228 ?.244 (5.791 ?6.197) 12 11 10 9 5 6 7 n/2 8 .016 ?.050 (0.406 ?1.270) .010 ?.020 (0.254 ?0.508) 45 0 ?8 typ .008 ?.010 (0.203 ?0.254) s14 0502 .053 ?.069 (1.346 ?1.752) .014 ?.019 (0.355 ?0.483) typ .004 ?.010 (0.101 ?0.254) .050 (1.270) bsc .245 min n 1 2 3 n/2 .160 .005 recommended solder pad layout .045 .005 .050 bsc .030 .005 typ inches (millimeters) note: 1. dimensions in 2. drawing not to scale 3. these dimensions do not include mold flash or protrusions. mold flash or protrusions shall not exceed .006" (0.15mm) information furnished by linear technology corporation is believed to be accurate and reliable. however, no responsibility is assumed for its use. linear technology corporation makes no represen- tation that the interconnection of its circuits as described herein will not infringe on existing patent rights.
lt1678/lt1679 16 sn16789 16789fs part number description comments lt1028/lt1128 ultralow noise precision op amps lowest noise 0.85nv/ hz lt1115 ultralow noise, low distortion audio op amp 0.002% thd, max noise 1.2nv/ hz lt1124/lt1125 dual/quad low noise, high speed precision op amps similar to lt1007 lt1126/lt1127 dual/quad decompensated low noise, high speed precision op amps similar to lt1037 lt1226 low noise, very high speed op amp 1ghz, 2.6nv/ hz, gain of 25 stable lt1498/lt1499 10mhz, 5v/ s, dual/quad rail-to-rail input and output op amps precision c-load tm stable lt1677 single version of lt1678/lt1679 rail-to-rail 3.2nv/ hz lt1792 low noise, precision jfet input op amp 4.2nv/ hz, 10fa/ hz lt1793 low noise, picoampere bias current op amp 6nv/ hz, 1fa/ hz, i b = 10pa max lt1806 low noise, 325mhz rail-to-rail input and output op amp 3.5nv/ hz lt1881/lt1882 dual/quad rail-to-rail output picoamp input precision op amps c load to 1000pf, i b = 200pa max lt1884/lt1885 dual/quad rail-to-rail output picoamp input precision op amps 2.2mhz bandwidth, 1.2v/ s sr c-load is a trademark of linear technology corporation. linear technology corporation 1630 mccarthy blvd., milpitas, ca 95035-7417 (408) 432-1900 fax: (408) 434-0507 www.linear.com ? linear technology corporation 2003 lt/tp 0104 1k ?printed in usa typical applicatio u related parts + + 2 1 1 2 350 ? 350 ? 350 ? 350 ? 5,6,7,8 3 1 100k 4 2 2x siliconix si9801 v ref v ref 5,6,7,8 3 1 100k 4 2 v ref 1/2 lt1678 1/2 lt1678 100 ? 0.1% 0.047 f 0.047 f 1k 0.1% 1k 0.1% 10 ? 10 ? 1 f 1 f 100 ? 100 ? 10 f 0.1 f 7v 5v lt1461-5 ltc2440 in + in ref + ref 2s 16789 ta02 bridge reversal eliminates 1/f noise and offset drift of a low noise, non-autozeroed, bipolar amplifier. circuit gives 14nv noise level or 19 effective bits over a 10mv span

▲Up To Search▲

Price & Availability of LT1679ISPBF

	To Download LT1679ISPBF Datasheet File
If you can't view the Datasheet, Please click here to try to view without PDF Reader .