20V, Ultra-Precision, Low-Noise Op Amps MAX44250/MAX44251/ MAX Benefits and Features. General Description

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1 MAX/MAX/ V, Ultra-Precision, Low-Noise Op Amps General Description The MAX/MAX/ are V, ultraprecision, low-noise, low-drift amplifiers that offer nearzero 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 /f noise. These single, dual, and quad devices feature rail-to-rail outputs, operate from a single.v to V supply or dual ±.V to ±V supplies and consume only.ma per channel, while providing.9nv/ Hz input-referred voltage noise. The ICs are unity-gain stable with a gainbandwidth product of MHz. With excellent specifications such as offset voltage of µv (max), drift of 9nV/ C (max), and nv P-P noise in.hz to Hz, the ICs are ideally suited for applications requiring ultra-low noise and DC precision such as interfacing with pressure sensors, strain gauges, precision weight scales, and medical instrumentation. The ICs are available in -pin SOT, -pin SOT, -pin µmaxm, and -pin SO packages and are rated over the - C to C temperature range. Ordering Information appears at end of data sheet. Benefits and Features High Accuracy Enables Precision Signal Chain Acquisition μv Input Offset Voltage (max) at oom Temperature TCV OS of 9nV/ C (max) Low.9nV/ Hz Input-eferred Voltage Noise nv P-P in.hz to Hz MHz Gain-Bandwidth Product ail-to-ail Output Fast ns Settling Time.V to V Power-Supply ange Supports Wide ange of Sensors Integrated EMI Filter educes Impact of adio Frequency Interference on Signal Chain Performance Applications Strain Gauges Pressure Transducers Medical Instrumentation Precision Instrumentation Load Cell and Bridge Transducer Amplification Functional Diagrams appear at end of data sheet. Typical Operating Circuit V.V V MAX BUFFE V V OUT MAX -V V G G G MAX BUFFE V EF V IN MAXOUTPUT MICO- POCESSO V -V V IN- BUFFE MAX.V C -V µmax is a registered trademark of Maxim Integrated Products, Inc. 9-; ev ; /

2 MAX/MAX/ V, Ultra-Precision, Low-Noise Op Amps Absolute Maximum atings Supply Voltage ( to )...-.V to V All Other Pins...( -.V) to (.V) Short-Circuit Duration to Either Supply ail... s Continuous Input Current (any pin)... ±ma Differential Input Voltage... ±V Maximum Power Dissipation (T A = C) -Pin SOT (derate.mw/ C above C)...mW -Pin SOT (derate 9.mW/ C above C)...mW µmax (derate. mw/ C above C)...mW SO (derate. mw/ C above C)...mW Operating Temperature ange... - C to NC Junction Temperature...NC Storage Temperature ange... - C to NC Lead Temperature (soldering, s)... NC Soldering Temperature (reflow)... NC Stresses beyond those listed under Absolute Maximum atings may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability. Package Thermal Characteristics (Note ) -Pin SOT Junction-to-Ambient Thermal esistance (Θ JA ).... C/W Junction-to-Case Thermal esistance (Θ JC )... C/W -Pin SOT Junction-to-Ambient Thermal esistance (Θ JA )... 9 C/W Junction-to-Case Thermal esistance (Θ JC )... C/W µmax Junction-to-Ambient Thermal esistance (Θ JA )... C/W Junction-to-Case Thermal esistance (Θ JC )... C/W SO Junction-to-Ambient Thermal esistance (Θ JA )... C/W Junction-to-Case Thermal esistance (Θ JC )... C/W Note : Package thermal resistances were obtained using the method described in JEDEC specification JESD-, using a four-layer board. For detailed information on package thermal considerations, refer to Electrical Characteristics ( = V, = V, V IN = V IN- = /, L = ki to /, T A = - C to C, unless otherwise noted. Typical values are at T A = C.) (Note ) POWE SUPPLY PAAMETE SYMBOL CONDITIONS MIN TYP MAX UNITS Supply Voltage ange Guaranteed by PS. V Power-Supply ejection atio (Note ) Quiescent Current per Amplifier (MAX) Quiescent Current per Amplifier (MAX/) PS =.V to V, V CM = V db I DD I DD L = J L = J T A = NC.. -NC < T A < NC. T A = NC.. -NC < T A < NC. Power-Up Time t ON Fs DC SPECIFICATIONS Input Common-Mode ange V CM Guaranteed by CM test Common-Mode ejection atio (Note ) Input Offset Voltage (MAX) (Note ) CM T A = NC, V CM = -.V to ( -.V) -. -NC < T A < NC -. V OS T A = NC 9 FV ma ma V db Maxim Integrated

3 MAX/MAX/ V, Ultra-Precision, Low-Noise Op Amps Electrical Characteristics (continued) ( = V, = V, V IN = V IN- = /, L = ki to /, T A = - C to C, unless otherwise noted. Typical values are at T A = C.) (Note ) PAAMETE SYMBOL CONDITIONS MIN TYP MAX UNITS Input Offset Voltage (MAX/ )(Note ) Input Offset Voltage Drift (MAX) (Note ) Input Offset Voltage Drift (MAX/)(Note ) Input Bias Current (MAX) (Note ) Input Bias Current (MAX/ )(Note ) T A = NC V OS -NC < T A < NC TC V OS nv/nc TC V OS 9 nv/nc I B T A = NC pa T A = NC I B -NC < T A < NC Input Offset Current (Note ) I OS pa Open-Loop Gain (Note ) AVOL mv P V OUT P - mv, L = ki to / T A = NC -NC < T A < NC Output Short-Circuit Current To or Noncontinuous 9 ma Output Voltage Low (MAX) Output Voltage Low (MAX/) Output Voltage High (MAX) Output Voltage High (MAX/) AC SPECIFICATIONS L = ki to / V OL V OUT - L = ki to / 9 L = ki to / V OL V OUT - L = ki to / L = ki to / V OH - V OUT L = ki to / L = ki to / V OH - V OUT L = ki to / Input Voltage-Noise Density e N f = khz.9 nv/ Hz Input Voltage Noise.Hz < f < Hz nv P-P Input Current-Noise Density i N f = khz. pa/ Hz Input Capacitance C IN pf Gain-Bandwidth Product GBW MHz Phase Margin PM C L = pf Degrees Slew ate S A V = V/V, V OUT = V P-P V/Fs Capacitive Loading C L No sustained oscillation, A V = V/V pf V OUT = V P-P, f = khz - A Total Harmonic Distortion THD V = V/V, db L = ki to f = khz -9 / Settling Time To.%, V OUT = V step, A V = -V/V ns FV pa db mv mv mv mv Maxim Integrated

4 MAX/MAX/ V, Ultra-Precision, Low-Noise Op Amps Electrical Characteristics ( =.V, = V, V IN = V IN- = /, L = ki to /, T A = - C to C, unless otherwise noted. Typical values are at T A = C.) (Note ) PAAMETE SYMBOL CONDITIONS MIN TYP MAX UNITS POWE SUPPLY Quiescent Current Per Amplifier (MAX) Quiescent Current Per Amplifier (MAX/)) I DD I DD L = J L = J T A = NC.. -NC < T A < NC. T A = NC.. -NC < T A < NC. Power-Up Time t ON Fs DC SPECIFICATIONS Input Common-Mode ange V CM Guaranteed by CM test Common-Mode ejection atio (Note ) Input Offset Voltage (MAX)(Note ) Input Offset Voltage (MAX/ )(Note ) Input Offset Voltage Drift (MAX)(Note ) Input Offset Voltage Drift (MAX/)(Note ) Input Bias Current (MAX)(Note ) Input Bias Current (MAX/ )(Note ) CM T A = NC, V CM = -.V to ( -.V) -. -NC < T A < NC 9 -. V OS. FV T A = NC. V OS -NC < T A < NC. TC V OS nv/nc TC V OS nv/nc I B pa T A = NC I B -NC < T A < NC Input Offset Current (Note ) I OS pa Open-Loop Gain (Note ) A VOL P - mv, L = ki to mv P V OUT / T A = NC -NC < T A < NC Output Short-Circuit Current To or Noncontinuous ma Output Voltage Low (MAX) Output Voltage Low (MAX/) L = ki to / V OL V OUT - L = ki to / L = ki to / V OL V OUT - L = ki to / L = ki to / 9 Output Voltage High V OH - V OUT L = ki to / 9 ma ma V db FV pa db mv mv mv Maxim Integrated

5 MAX/MAX/ V, Ultra-Precision, Low-Noise Op Amps Electrical Characteristics (continued) ( =.V, = V, V IN = V IN- = /, L = ki to /, T A = - C to C, unless otherwise noted. Typical values are at T A = C.) (Note ) PAAMETE SYMBOL CONDITIONS MIN TYP MAX UNITS AC SPECIFICATIONS Input Voltage-Noise Density e N f = khz. nv/ Hz Input Voltage Noise.Hz < f < Hz nv P-P Input Current-Noise Density i N f = khz. pa/ Hz Input Capacitance C IN pf Gain-Bandwidth Product GBW MHz Phase Margin PM C L = pf Degrees Slew ate S A V = V/V, V OUT = V P-P, % to 9% V/Fs Capacitive Loading C L No sustained oscillation, A V = V/V pf Total Harmonic Distortion THD V OUT = V P-P, A V = V/V, V CM = /, L = ki to / f = khz - f = khz - db Settling Time To.%, V OUT = V step, A V = -V/V ns Note : All devices are % production tested at T A = C. Temperature limits are guaranteed by design. Note : Guaranteed by design. Typical Operating Characteristics ( = V, = V, outputs have L = ki to /. T A = NC, unless otherwise specified.) PECENT OCCUENCE (%) OFFSET VOLTAGE HISTOGAM OFFSET VOLTAGE (µv) MAX toc PECENT OCCUENCE (%) INPUT OFFSET VOLTAGE DIFT HISTOGAM OFFSET VOLTAGE DIFT (µv/ C). MAX toc SUPPLY CUENT (ma) SUPPLY CUENT vs. SUPPLY VOLTAGE T A = C T A = C TA = C T A = - C SUPPLY VOLTAGE (V) T A = C SUPPLY CUENT PE AMPLIFIE MAX toc Maxim Integrated

6 MAX/MAX/ V, Ultra-Precision, Low-Noise Op Amps Typical Operating Characteristics (continued) ( = V, = V, outputs have L = ki to /. T A = NC, unless otherwise specified.)... SUPPLY CUENT vs. TEMPEATUE MAX toc INPUT OFFSET VOLTAGE vs. INPUT COMMON MODE MAX toc INPUT OFFSET VOLTAGE vs. TEMPEATUE MAX toc SUPPLY CUENT (ma) VOS (µv) VOS (µv).. SUPPLY CUENT PE AMPLIFIE. - - TEMPEATUE ( C) INPUT COMMON VOLTAGE (V) - - TEMPEATUE ( C) INPUT BIAS CUENT (pa) - INPUT BIAS CUENT vs. COMMON-MODE VOLTAGE I BIAS- T A = C T A = - C T A = C - I BIAS INPUT COMMON-MODE VOLTAGE (V) MAX toc IBIAS (pa) INPUT BIAS CUENT vs. TEMPEATUE POSITIVE I BIAS NEGATIVE I BIAS TEMPEATUE ( C) MAX toc CM (db) COMMON-MODE EJECTION ATIO vs. FEQUENCY -. k k k M M M FEQUENCY (Hz) MAX toc9 Maxim Integrated

7 MAX/MAX/ V, Ultra-Precision, Low-Noise Op Amps Typical Operating Characteristics (continued) ( = V, = V, outputs have L = ki to /. T A = NC, unless otherwise specified.) OUTPUT VOLTAGE HIGH (mv) OUTPUT VOLTAGE HIGH vs. OUTPUT SOUCE CUENT ( - V OH ) MAX toc OUTPUT VOLTAGE LOW (mv) OUTPUT VOLTAGE LOW vs. OUTPUT SINK CUENT MAX toc VOH (mv) OUTPUT VOLTAGE SWING HIGH vs. TEMPEATUE MAX toc L = ki to / OUTPUT SOUCE CUENT (ma) OUTPUT SINK CUENT (ma) - - TEMPEATUE ( C) VOL (mv) OUTPUT VOLTAGE SWING LOW vs. TEMPEATUE - - TEMPEATUE ( C) L = ki to / MAX toc OPEN-LOOP GAIN (db) - - OPEN-LOOP GAIN vs. FEQUENCY -. k k k M M M FEQUENCY (Hz) MAX toc INPUT VOLTAGE NOISE (nv/ Hz) INPUT VOLTAGE NOISE vs. FEQUENCY k k k FEQUENCY (Hz) MAX toc INPUT VOLTAGE.Hz TO Hz NOISE MAX toc.µv/div INPUT CUENT NOISE (pa/ Hz) INPUT CUENT NOISE vs. FEQUENCY MAX toc MAGNITUDE (db) SMALL-SIGNAL ESPONSE V IN = mv P-P MAX toc s/div k k FEQUENCY (Hz) - k k k M M M FEQUENCY (Hz) Maxim Integrated

8 MAX/MAX/ V, Ultra-Precision, Low-Noise Op Amps Typical Operating Characteristics (continued) ( = V, = V, outputs have L = ki to /. T A = NC, unless otherwise specified.) MAGNITUDE (db) LAGE-SIGNAL ESPONSE -. k k k M M M SUPPLY VOLTAGE (V/div) V VOLTAGE (V/div) V V OFFSET (mv/div) = = V FEQUENCY (Hz) POWE-UP TIME µs TIME (µs/div) V IN = V P-P = V = V MAX toc MAX toc9 MAGNITUDE (db) VOLTAGE (mv/div) SMALL-SIGNAL STEP ESPONSE vs. TIME MAX toc A V = V/V V IN = mv P-P INPUT OUTPUT TIME (µs/div) TOTAL HAMONIC DISTOTION vs. FEQUENCY - k k k FEQUENCY (Hz) MAX toc MAGNITUDE (db) VOLTAGE (V/div) LAGE-SIGNAL STEP ESPONSE vs. TIME MAX toc A V = V/V V IN = V P-P INPUT OUTPUT TIME (µs/div) TOTAL HAMONIC DISTOTION vs. INPUT VOLTAGE V CC =.V INPUT VOLTAGE (V) MAX toc ESISTIVE LOAD (ki) 9 STABILITY vs. CAPACITIVE AND ESISTIVE LOAD IN PAALLEL WITH C L STABLE UNSTABLE MAX toc ISO (I) STABILITY vs. CAPACITIVE AND ISO IN SEIES WITH C LOAD STABLE UNSTABLE MAX toc EMI (db) MAX EMI MAX toc k k CAPACITIVE LOAD (pf) k k k CAPACITIVE LOAD (pf), FEQUENCY (MHz) Maxim Integrated

9 MAX/MAX/ V, Ultra-Precision, Low-Noise Op Amps Pin Configurations TOP VIEW OUTA MAX N.C. INA- INA MAX N.C. OUTA INA INA- µmax N.C. SOT OUTA OUTD MAX OUTA INA- INA OUTB INB- INB OUTB INB- INB OUTA INA- INA MAX µmax INA- IND- INA IND INB INC INB- 9 INC- SOT OUTB OUTC SO Pin Description PIN MAX MAX NAME FUNCTION SOT µmax SOT µmax SO OUTA Channel A Output INA- Channel A Negative Input INA Channel A Positive Input Negative Supply Voltage INB Channel B Positive Input INB- Channel B Negative Input OUTB Channel B Output Positive Supply Voltage OUTC Channel C Output 9 INC- Channel C Negative Input INC Channel C Positive Input IND Channel D Positive Input IND- Channel D Negative Input OUTD Channel D Output,, N.C. No Connection Maxim Integrated 9

10 MAX/MAX/ V, Ultra-Precision, Low-Noise Op Amps Detailed Description The MAX/MAX/ are high-precision amplifiers that have less than FV of typical inputreferred offset and low flicker noise. These characteristics are achieved through an autozeroing technique that samples and finds repeating patterns of signal to cancel the input offset voltage and /f noise of the amplifier. Autozero The ICs feature an autozero circuit that allows the devices to achieve less than FV (max) of input offset voltage at room temperature and eliminate the /f noise. Noise Suppression Flicker noise, inherent in all active devices, is inversely proportional to frequency presented. Charges at the oxide-silicon interface that are trapped-and-released by MOSFET oxide occurs at low frequency more often. For this reason, flicker noise is also called /f noise. Electromagnetic interference (EMI) noise occurs at higher frequency that results in malfunction or degradation of electrical equipment. The ICs have an input EMI filter to avoid the output getting affected by radio frequency interference. The EMI filter composed of passive devices presents significant higher impedance to higher frequency. High Supply Voltage ange The ICs feature.ma current consumption per channel and a voltage supply range from either.v to V single supply or ±.V to ±V split supply. Applications Information The ICs are ultra-high-precision operational amplifiers with a high supply voltage range designed for load cell, medical instrumentation and precision instrument applications. These devices are also designed to interface with pressure transducers and are ideal for precision weight scale application as shown in Figure. V.V V MAX BUFFE -V V V V OUT MAX G G G MAX BUFFE V EF V IN MAXOUTPUT MICO- POCESSO V -V V IN- BUFFE MAX.V C -V Figure. Weight Scale Application Circuit Maxim Integrated

11 MAX/MAX/ V, Ultra-Precision, Low-Noise Op Amps ADC Buffer Amplifier The MAX/MAX/'s low input offset voltage, low noise, and fast settling time make these amplifiers ideal for ADC buffers. Weigh scales are one application that often require a low-noise, high-voltage amplifier in front of an ADC. Figure details an example of a load cell and amplifier driven from the same QV supplies, along with the MAX -bit delta sigma ADC. Load cells produce a very small voltage change at their outputs, therefore driving the excitation source with a higher voltage produces a wider dynamic range that can be measured at the ADC inputs. The MAX ADC operates from a single.v to.v analog supply, offers -bit noise-free resolution and.mw power dissipation. The MAX also offers > db rejection at Hz and Hz. This ADC is part of a family of -, -, -, and -bit delta sigma ADCs with high precision and < mw power dissipation. The MAX/MAX/'s low input offset voltage and low noise allow a gain circuit prior to the MAX without losing any dynamic range at the ADC. Error Budget Example When using the ICs as an ADC buffer in strain gauge application, the temperature drift should be taken into consideration to determine maximum input signal. A typical strain gauge has sensitivity specification of just mv/v at rated out load. This means that when the strain gauge load cell is powered with V, the full-scale output voltage is mv. In this application, both offset voltage and drift are critical parameters that directly affect the accuracy of measurement. Even though offset voltage could be calibrated out, its drift over temperature is still a problem. The ICs, with a typical offset drift of nv/ C, guarantee that the drift over a C range is only nv. Setting this equal to. LSB in a -bit system yields a full-scale range of mv. With a single V supply, an acceptable closed-loop gain of V/V provides sufficient gain while maintaining headroom. Precision Low-Side Current Sensing The ICs autozero feature produces ultra-low offset voltage and drift, making them ideal for precision current-sensing applications. Figure shows the ICs in a low-side current-sense configuration. This circuit produces an accurate output voltage, V OUT equal to I LOAD x SENSE x ( /). I LOAD SENSE V SUPPLY Figure. Low-Side Current Sensing MAX OUT Maxim Integrated

12 MAX/MAX/ V, Ultra-Precision, Low-Noise Op Amps Functional Diagrams TOP VIEW OUT OUTA INB- INA- INA MAX OUTB IN IN- MAX INB N.C. MAX N.C. VDD OUTA IND- INA- INA OUTD IN- IND IN OUT N.C. INB INC 9 INB- INC- OUTB OUTC Chip Information POCESS: BiCMOS Ordering Information PAT TEMP ANGE PIN- PACKAGE Denotes a lead(pb)-free/ohs-compliant package. TOP MAK MAXAUK -NC to NC SOT AFMA MAXAUA -NC to NC FMAX MAXAKA -NC to NC SOT AEC MAXAUA -NC to NC FMAX ASD -NC to NC SO Maxim Integrated

13 MAX/MAX/ V, Ultra-Precision, Low-Noise Op Amps Package Information For the latest package outline information and land patterns (footprints), go to Note that a, #, or - in the package code indicates ohs status only. Package drawings may show a different suffix character, but the drawing pertains to the package regardless of ohs status. PACKAGE TYPE PACKAGE CODE OUTLINE NO. LAND PATTEN NO. SOT U - 9- SOT K - 9- FMAX U SO SM Maxim Integrated

14 MAX/MAX/ V, Ultra-Precision, Low-Noise Op Amps evision History EVISION NUMBE EVISION DATE DESCIPTION PAGES CHANGED / Initial release / eleased the and updated the Typical Operating Characteristics,, / Added the MAX to the data sheet, added MAX EMI graph to Typical Operating Characteristics, and revised Figure / Updated General Description, Typical Operating Circuit, and Figure, / Corrected Package Information / Added the Benefits and Features section For pricing, delivery, and ordering information, please contact Maxim Direct at --9-, or visit Maxim Integrated s website at Maxim Integrated cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim Integrated product. No circuit patent licenses are implied. Maxim Integrated 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 guidance. Maxim Integrated and the Maxim Integrated logo are trademarks of Maxim Integrated Products, Inc. Maxim Integrated Products, Inc.