general description the max4238/max4239 are low-noise, low-drift, ultra- high precision amplifiers that offer near-zero dc offset and drift through the use of patented autocorrelating zeroing techniques. this method constantly measures and compensates the input offset, eliminating drift over time and temperature and the effect of 1/f noise. both devices feature rail-to-rail outputs, operate from a single 2.7v to 5.5v supply, and consume only 600?. an active- low shutdown mode decreases supply current to 0.1?. the max4238 is unity-gain stable with a gain-band- width product of 1mhz, while the decompensated max4239 is stable with a v 10v/v and a gbwp of 6.5mhz. the max4238/max4239 are available in 8-pin narrow so, 6-pin tdfn and sot23 packages. applications thermocouples strain gauges electronic scales medical instrumentation instrumentation amplifiers features ultra-low, 0.1 v offset voltage 2.0 v (max) at +25c 2.5 v (max) at -40c to +85c 3.5 v (max) at -40c to +125c low 10nv/c drift specified over the -40c to +125c automotive temperature range low noise: 1.5 v p-p from dc to 10hz 150db a vol , 140db psrr, 140db cmrr high gain-bandwidth product 1mhz (max4238) 6.5mhz (max4239) 0.1 a shutdown mode rail-to-rail output (r l = 1k ? ) low 600 a supply current ground-sensing input single 2.7v to 5.5v supply voltage range available in a space-saving 6-pin sot23 and tdfn packages max4238/max4239 ultra-low offset/drift, low-noise, precision sot23 amplifiers ________________________________________________________________ maxim integrated products 1 max4238/ max4239 360 ? strain gauge 18k ? 18k ? ain 5v a v = 100 adc typical application circuit 19-2424; rev 3; 8/11 for pricing, delivery, and ordering information, please contact maxim direct at 1-888-629-4642, or visit maxim? website at www.maxim-ic.com. pin configurations appear at end of data sheet. note: all devices are specified over the -40? to +125? oper- ating temperature range. + denotes a lead(pb)-free/rohs-compliant package. * ep = exposed paddle. /v denotes an automotive-qualified part. ordering information part pin-package top mark max4238 aut-t 6 sot23 aazz max4238aut/v+t 6 sot23 max4238asa 8 so max4238att+t 6 tdfn-ep* +ang max4239 aut-t 6 sot23 abaa max4239aut/v+t 6 sot23 max4239asa 8 so max4239att+t 6 tdfn-ep* +anh selector guide part minimum stable gain gain bandwidth (mhz) max4238 1v/v 1 max4239 10v/v 6.5
max4238/max4239 ultra-low offset/drift, low-noise, precision sot23 amplifiers 2 _______________________________________________________________________________________ absolute maximum ratings electrical characteristics (2.7v v cc 5.5v, v cm = v gnd = 0v, v out = v cc /2, r l = 10k ? connected to v cc /2, shdn = v cc , t a = +25 c , unless otherwise noted.) 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. power-supply voltage (v cc to gnd).......................................6v all other pins ................................(v gnd - 0.3v) to (v cc + 0.3v) output short-circuit duration (out shorted to v cc or gnd) ...............................continuous continuous power dissipation (t a = +70?) 6-pin plastic sot23 (derate 9.1mw/? above +70?) ...............................727mw 8-pin plastic so (derate 5.88mw/? above +70?) ....471mw 6-pin tdfn-ep (derate 18.2mw above +70?) .........1454mw operating temperature range .........................-40? to +125? junction temperature ......................................................+150? storage temperature range .............................-65? to +150? lead temperature (soldering, 10s) .................................+300? soldering temperature (reflow) lead(pb)-free packages.............................................+260? packages containing lead..........................................+240? parameter symbol conditions min typ max units input offset voltage v os (note 1) 0.1 2 v long-term offset drift 50 nv/1000hr input bias current i b (note 2) 1 pa input offset current i os (note 2) 2 pa peak-to-peak input noise voltage e np-p r s = 100 , 0.01hz to 10hz 1.5 v p-p input voltage-noise density e n f = 1khz 30 nv/ hz common-mode input voltage range v cm inferred from cmrr test v gnd - 0.1 v cc - 1.3 v common-mode rejection ratio cmrr -0.1v v cm v cc - 1.3v (note 1) 120 140 db power-supply rejection ratio psrr 2.7v v cc 5.5v (note 1) 120 140 db 0.05v v out v cc - 0.05v (note 1) r l = 10k 125 150 large-signal voltage gain a vol 0.1v v out v cc - 0.1v (note 1) r l = 1k 125 145 db v cc - v oh 4 10 r l = 10k v ol 4 10 v cc - v oh 35 50 output voltage swing v oh /v ol r l = 1k v ol 35 50 mv output short-circuit current to either supply 40 ma output leakage current 0 v out v cc , shdn = gnd (note 2) 0.01 1 a max4238 0.35 slew rate v cc = 5v, c l = 100pf, v out = 2v step max4239 1.6 v/s max4238 1 gain-bandwidth product gbwp r l = 10k , c l = 100pf, measured at f = 100khz max4239 6.5 mhz max4238 1 minimum stable closed-loop gain r l = 10k , c l = 100pf, phase margin = 60 max4239 10 v/v
max4238/max4239 ultra-low offset/drift, low-noise, precision sot23 amplifiers _______________________________________________________________________________________ 3 electrical characteristics (continued) (2.7v v cc 5.5v, v cm = v gnd = 0v, v out = v cc /2, r l = 10k ? connected to v cc /2, shdn = v cc , t a = +25 c , unless otherwise noted.) parameter symbol conditions min typ max units max4238 1000 maximum closed-loop gain r l = 10k , c l = 100pf, phase margin = 60 max4239 6700 v/v 0.1% (10 bit) 0.5 0.025% (12 bit) 1.0 0.006% (14 bit) 1.7 settling time -1v step 0.0015% (16 bit) 2.3 ms 0.1% (10 bit) 3.3 0.025% (12 bit) 4.1 0.006% (14 bit) 4.9 overload recovery time a v = 10 (note 4) 0.0015% (16 bit) 5.7 ms 0.1% (10 bit) 1.8 0.025% (12 bit) 2.6 0.006% (14 bit) 3.4 startup time a v = 10 0.0015% (16 bit) 4.3 ms supply voltage range v cc inferred by psrr test 2.7 5.5 v shdn = v cc , no load, v cc = 5.5v 600 850 supply current i cc shdn = gnd, v cc = 5.5v 0.1 1 a shutdown logic-high v ih 2.2 v shutdown logic-low v il 0.8 v shutdown input current 0v v shdn v cc 0.1 1 a
max4238/max4239 ultra-low offset/drift, low-noise, precision sot23 amplifiers 4 _______________________________________________________________________________________ electrical characteristics (2.7v v cc 5.5v, v cm = gnd = 0v, v out = v cc /2, r l = 10k ? connected to v cc /2, shdn = v cc , t a = -40 c to +125 c , unless other- wise noted.) (note 5) parameter symbol conditions min typ max units t a = -40c to +85c 2.5 input offset voltage v os (note 1) t a = -40c to +125c 3.5 v input offset drift tcv os (note 1) 10 nv/c common-mode input voltage range v cm inferred from cmrr test v gnd - 0.05 v cc - 1.4 v t a = -40c to +85c 115 common-mode rejection ratio cmrr v gnd - 0.05v v cm v cc - 1.4v (note 1) t a = -40c to +125c 90 db power-supply rejection ratio psrr 2.7v v cc 5.5v (note 1) 120 db t a = -40c to +85c 125 r l = 10k , 0.1v v out v cc - 0.1v (note 1) t a = -40c to +125c 95 db 0.1v v out v cc - 0.1v, t a = -40c to +85c 120 large-signal voltage gain a vol r l = 1k (note 1) 0.2v v out v cc - 0.2v, t a = -40c to +125c 80 db v cc - v oh 20 r l = 10k v ol 20 v cc - v oh 100 output voltage swing v oh /v ol r l = 1k v ol 100 mv output leakage current 0v v out v cc , shdn = gnd (note 3) 2 a supply voltage range v cc inferred by psrr test 2.7 5.5 v shdn = v cc , no load, v cc = 5.5v 900 supply current i cc shdn = gnd, v cc = 5.5v 2 a shutdown logic high v ih 2.2 v shutdown logic low v il 0.7 v shutdown input current 0v v shdn v cc 2 a note 1 : guaranteed by design. thermocouple and leakage effects preclude measurement of this parameter during production testing. devices are screened during production testing to eliminate defective units. note 2 : in+ and in- are gates to cmos transistors with typical input bias current of 1pa. cmos leakage is so small that it is impractical to test and guarantee in production. devices are screened during production testing to eliminate defective units. note 3 : leakage does not include leakage through feedback resistors. note 4 : overload recovery time is the time required for the device to recover from saturation when the output has been driven to either rail. note 5 : specifications are 100% tested at t a = +25?, unless otherwise noted. limits over temperature are guaranteed by design.
max4238/max4239 ultra-low offset/drift, low-noise, precision sot23 amplifiers _______________________________________________________________________________________ 5 typical operating characteristics (v cc = 5v, v cm = 0v, r l = 10k ? connected to v cc /2, shdn = v cc , t a = +25?, unless otherwise noted.) max4238 gain and phase vs. frequency max4238/39 toc09 frequency (hz) gain and phase (db/degrees) 1m 100k 10k 1k -160 -140 -120 -100 -80 -60 -40 -20 0 20 40 60 80 -180 100 10m v cc = 5v gain = 40db r l = 10k ? c l = 68pf max4238 gain and phase vs. frequency max4238/39 toc07 frequency (hz) gain and phase (db/degrees) 1m 100k 10k 1k -160 -140 -120 -100 -80 -60 -40 -20 0 20 40 60 80 -180 100 10m v cc = 5v gain = 60db r l = 10k ? c l = 100pf max4238 gain and phase vs. frequency max4238/39 toc06 frequency (hz) gain and phase (db/degrees) 1m 100k 10k 1k -160 -140 -120 -100 -80 -60 -40 -20 0 20 40 60 80 -180 100 10m v cc = 5v gain = 60db r l = 10k ? c l = 0pf output low voltage vs. output sink current max4238/39 toc05 sink current (ma) output low voltage (v) 15 10 5 0.05 0.10 0.15 0.20 0.25 0.35 0.30 0 020 v cc = 2.7v v cc = 5v output high voltage vs. output source current max4238/39 toc04 source current (ma) output high voltage (v) 15 10 5 0.05 0.10 0.15 0.20 0.25 0.30 0 020 v oh = v cc - v out v cc = 2.7v v cc = 5v offset voltage vs. common-mode voltage max4238/39 toc03 common-mode voltage (v) offset voltage ( v) 2.7 1.8 0.9 -0.2 0 0.2 0.4 -0.4 0 3.6 t a = +125 c t a = +25 c t a = -40 c offset voltage vs. supply voltage max4238/39 toc02 supply voltage (v) offset voltage ( v) 4.8 4.1 3.4 -0.2 0 0.2 0.4 -0.4 2.7 5.5 t a = +125 c t a = +25 c t a = -40 c input offset distribution max4238/39 toc01 offset voltage ( v) percentage of units (%) 1.5 1.2 0.9 0.6 0.3 0 -0.3 -0.6 -0.9 -1.2 -1.5 10 20 30 40 50 0 max4238 gain and phase vs. frequency max4238/39 toc08 frequency (hz) gain and phase (db/degrees) 1m 100k 10k 1k -160 -140 -120 -100 -80 -60 -40 -20 0 20 40 60 80 -180 100 10m v cc = 5v gain = 40db r l = 10k ? c l = 0pf
max4238/max4239 ultra-low offset/drift, low-noise, precision sot23 amplifiers 6 _______________________________________________________________________________________ typical operating characteristics (continued) (v cc = 5v, v cm = 0v, r l = 10k ? connected to v cc /2, shdn = v cc , t a = +25?, unless otherwise noted.) common-mode rejection ratio vs. frequency max4238/39 toc14 frequency (khz) cmrr (db) 100 10 0.1 1 -140 -120 -100 -80 -60 -40 -20 0 0.01 1000 -160 power-supply rejection ratio vs. frequency max4238/39 toc13 frequency (khz) psrr (db) 100 10 0.1 1 -140 -120 -100 -80 -60 -40 -20 0 -160 0.01 1000 max4239 gain and phase vs. frequency max4238/39 toc10 frequency (hz) gain and phase (db/degrees) 1e+6 1e+5 1e+4 1e+3 -160 -140 -120 -100 -80 -60 -40 -20 0 20 40 60 80 -180 1e+2 1e+7 v cc = 5v gain = 40db r l = 10k ? c l = 0pf max4239 small-signal transient response max4238/39 toc17 a v = 10v/v r l = 2k ? c l = 100pf 10 s/div out in 500mv/div 50mv/div max4238 large-signal transient response max4238/39 toc15 a v = 1v/v r l = 2k ? c l = 100pf 10 s/div out in 1v/div 1v/div max4239 gain and phase vs. frequency max4238/39 toc11 frequency (hz) gain and phase (db/degrees) 1e+6 1e+5 1e+4 1e+3 -160 -140 -120 -100 -80 -60 -40 -20 0 20 40 60 80 -180 1e+2 1e+7 v cc = 5v gain = 40db r l = 10k ? c l = 100pf overvoltage recovery time max4238/39 toc18 a v = 100v/v r l = 10k ? v cc = 2.5v v ee = -2.5v 400 s/div 0 0 out in 1v/div 50mv/div max4238 small-signal transient response max4238/39 toc16 a v = 1v/v r l = 2k ? c l = 100pf 10 s/div out 50mv/div in 50mv/div supply current vs. supply voltage max4238/39 toc12 supply voltage (v) supply current ( a) 4 3 2 1 200 300 400 500 600 0 100 05 t a = +125 c t a = +25 c t a = -40 c
detailed description the max4238/max4239 are high-precision amplifiers that have less than 2.5? of input-referred offset and low 1/f noise. these characteristics are achieved through a patented autozeroing technique that samples and cancels the input offset and noise of the amplifier. the pseudorandom clock frequency varies from 10khz to 15khz, reducing intermodulation distortion present in chopper-stabilized amplifiers. offset error sources to achieve very low offset, several sources of error common to autozero-type amplifiers need to be consid- ered. the first contributor is the settling of the sampling capacitor. this type of error is independent of input- source impedance, or the size of the external gain-set- ting resistors. maxim uses a patented design technique to avoid large changes in the voltage on the sampling capacitor to reduce settling time errors. the second error contributor, which is present in both autozero and chopper-type amplifiers, is the charge injection from the switches. the charge injection appears as current spikes at the input, and combined with the impedance seen at the amplifier? input, con- tributes to input offset voltage. minimize this feedthrough by reducing the size of the gain-setting resistors and the input-source impedance. a capacitor in parallel with the feedback resistor reduces the amount of clock feedthrough to the output by limiting the closed-loop bandwidth of the device. the design of the max4238/max4239 minimizes the effects of settling and charge injection to allow specifi- cation of an input offset voltage of 0.1? (typ) and less than 2.5? over temperature (-40? to +85?). 1/f noise 1/f noise, inherent in all semiconductor devices, is inversely proportional to frequency. 1/f noise increases 3db/octave and dominates amplifier noise at lower fre- quencies. this noise appears as a constantly changing voltage in series with any signal being measured. the max4238/max4239 treat 1/f noise as a slow varying offset error, inherently canceling the 1/f noise. max4238/max4239 ultra-low offset/drift, low-noise, precision sot23 amplifiers _______________________________________________________________________________________ 7 typical operating characteristics (continued) (v cc = 5v, v cm = 0v, r l = 10k ? connected to v cc /2, shdn = v cc , t a = +25?, unless otherwise noted.) shutdown waveform max4238/39 toc20 r l = 10k ? c l = 100pf 10 s/div out 2v/div 1v/div shdn dc to 10hz noise max4238/39 toc19 v cc = 2.5v v ee = -2.5v 1s/div out 2 v/div pin tdfn sot23 so name function 1 1 6 out amplifier output 2 2 4 gnd ground 3 3 3 in+ noninverting input 4 4 2 in- inverting input 5 5 1 shdn shutdown input. active-low shutdown, connect to v cc for normal operation. 6 6 7 v cc positive power supply 5, 8 n.c. no connection. not internally connected. ep exposed pad (tdfn only). connect ep to gnd. pin description
max4238/max4239 output overload recovery autozeroing amplifiers typically require a substantial amount of time to recover from an output overload. this is due to the time it takes for the null amplifier to correct the main amplifier to a valid output. the max4238/ max4239 require only 3.3ms to recover from an output overload (see electrical characteristics and typical operating characteristics ). shutdown the max4238/max4239 feature a low-power (0.1?) shutdown mode. when shdn is pulled low, the clock stops and the device output enters a high-impedance state. connect shdn to v cc for normal operation. applications information minimum and maximum gain configurations the max4238 is a unity-gain stable amplifier with a gain- bandwidth product (gbwp) of 1mhz. the max4239 is decompensated for a gbwp of 6.5mhz and is stable with a gain of 10v/v. unlike conventional operational ampli- fiers, the max4238/max4239 have a maximum gain specification. to maintain stability, set the gain of the max4238 between a v = 1000v/v to 1v/v, and set the gain of the max4239 between a v = 6700v/v and 10v/v. adc buffer amplifier the low offset, fast settling time, and 1/f noise cancella- tion of the max4238/max4239 make these devices ideal for adc buffers. the max4238/max4239 are well suited for low-speed, high-accuracy applications such as strain gauges (see typical application circuit ). error budget example when using the max4238/max4239 as an adc buffer, the temperature drift should be taken into account when determining the maximum input signal. with a typical off- set drift of 10nv/?, the drift over a 10? range is 100nv. setting this equal to 1/2lsb in a 16-bit system yields a full-scale range of 13mv. with a single 2.7v supply, an acceptable closed-loop gain is a v = 200. this provides sufficient gain while maintaining headroom. ultra-low offset/drift, low-noise, precision sot23 amplifiers 8 _______________________________________________________________________________________ out n.c. gnd 1 2 8 7 n.c. v cc in- in+ shdn so top view 3 4 6 5 max4238/ max4239 max4238/ max4239 gnd in- in+ 16v cc 5 shdn out sot23 2 34 max4238/ max4239 6 v cc 5 shdn 4 in- out gnd in+ 1 ep* 23 tdfn (3mm x 3mm x 0.8mm) + *connect ep to gnd. pin configurations chip information process: bicmos package information for the latest package outline information and land patterns (footprints), go to www.maxim-ic.com/packages . note that a ?? ?? or ??in the package code indicates rohs status only. package drawings may show a different suffix character, but the drawing pertains to the package regardless of rohs status. package type package code outline no. land pattern no. 6 sot23 u6f-6 21-0058 90-0175 8 so s8-4 21-0041 90-0096 6 tdfn t633+2 21-0137 90-0058
max4238/max4239 ultra-low offset/drift, low-noise, precision sot23 amplifiers 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. the parametric values (min and max limits) shown in the electrical characteristics table are guaranteed. other parametric values quoted in this data sheet are provided for guidanc e. 9 _____________________maxim integrated products, 120 san gabriel drive, sunnyvale, ca 94086 408-737-7600 2011 maxim integrated products maxim is a registered trademark of maxim integrated products, inc. revision history revision number revision date description pages changed 2 5/06 3 8/11 added max4238 and max4239 automotive-qualified parts 1
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