Ultra-Low Noise, Precision Operational Amplifiers …

1 FEATURES low noise : Hz max at 1kHz LOW OFFSET: 100 V max LOW DRIFT: V/ C HIGH OPEN-LOOP GAIN: 117dB min HIGH COMMON-MODE REJECTION: 100dB min HIGH POWER-SUPPLY REJECTION: 94dB min FITS OP-07, OP-05, AD510, AND AD517 SOCKETSU ltra- low noise , PrecisionOPERATIONAL AMPLIFIERSAPPLICATIONS Precision INSTRUMENTATION DATA ACQUISITION TEST EQUIPMENT PROFESSIONAL AUDIO EQUIPMENT TRANSDUCER Amplifiers RADIATION HARD EQUIPMENTOPA27 OPA37 OPA27 OPA27 SBOS135C JANUARY 1984 REVISED AUGUST 2005 DESCRIPTIONThe OPA27 and OPA37 are Ultra-Low noise , high-precisionmonolithic Operational thin-film resistors provide excellent long-termvoltage offset stability and allow superior voltage offsetcompared to common zener-zap unique bias current cancellation circuit allows bias andoffset current specifications to be met over the full 40 C to+85 C temperature OPA27 is internally compensated for unity-gain decompensated OPA37 requires a closed-loop gain Texas Instruments OPA27 and OPA37 are improvedreplacements for the industry-standard OP-27 and DATA information is current as of publication conform to specifications per the terms of Texas Instrumentsstandard warranty.

2 Production processing does not necessarily includetesting of all 1984-2005, Texas Instruments IncorporatedPlease be aware that an important notice concerning availability, standard warranty, and use in critical applications ofTexas Instruments semiconductor products and disclaimers thereto appears at the end of this data trademarks are the property of their respective +VCC VCC+In InTrimTrim8764123 OPA27, ViewPIN CONFIGURATIONABSOLUTE MAXIMUM RATINGS(1)Supply Voltage .. 22 VInternal Power Dissipation (2).. 500mWInput Voltage .. VCCO utput Short-Circuit Duration (3).. IndefiniteDifferential Input Voltage (4).. Input Current (4).. 25mAStorage Temperature Range .. 55 C to +125 COperating Temperature Range .. 40 C to +85 CLead Temperature:P (soldering, 10s) .. +300 CU (soldering, 3s) .. +260 CNOTES: (1) Stresses above these ratings may cause permanent to absolute maximum conditions for extended periods may degradedevice reliability.

3 (2) Maximum package power dissipation versus ambienttemperature. (2) To common with VCC = 15V. (4) The inputs are protected byback-to-back diodes. Current limiting resistors are not used in order to achievelow noise . If differential input voltage exceeds , the input current shouldbe limited to JADRAWINGMARKINGOPA27 DIP-8100 C/WPOPA27 GPOPA27SO-8160 C/WDOPA27 UOPA37 DIP-8100 C/WPOPA37 GPOPA37SO-8160 C/WDOPA37 UNOTE: (1) For the most current package and ordering information, see thePackage Option Addendum located at the end of this document, or see the TIwebsite at INFORMATION(1)ELECTROSTATICDISCHARGE SENSITIVITYThis integrated circuit can be damaged by ESD. Texas Instru-ments recommends that all integrated circuits be handled withappropriate precautions. Failure to observe proper handlingand installation procedures can cause damage can range from subtle performance degradationto complete device failure.

4 Precision integrated circuits may bemore susceptible to damage because very small parametricchanges could cause the device not to meet its Trim+VCC In+In VCCO utputNCNC = No ConnectionOffset TrimOPA27, CHARACTERISTICSAt VCC = 15V and TA = +25 C, unless otherwise noise (6)Voltage, fO = HzfO = HzfO = HzfB = to VPPC urrent,(1) fO = HzfO = HzfO = HzOFFSET VOLTAGE(2)Input Offset Voltage 25 100 VAverage Drift(3)TA MIN to TA MAX (6) V/ CLong Term Stability(4) V/moSupply Rejection VCC = 4 to 18V94120dB VCC = 4 to 18V 1 20 V/VBIAS CURRENTI nput Bias Current 15 80nAOFFSET CURRENTI nput Offset Current1075nAIMPEDANCEC ommon-Mode2 || || pFVOLTAGE RANGEC ommon-Mode Input Range 11 RejectionVIN = 11 VDC100122dBOPEN-LOOP VOLTAGE GAIN, DCRL 2k 117124dBRL 1k 124dBFREQUENCY RESPONSEGain-Bandwidth Product(5)OPA275(6)8 MHzOPA3745(6)63 MHzSlew Rate(5)VO = 10V,RL = 2k OPA27, G = + (6) sOPA37, G = +511(6) sSettling Time, , G = +125 sOPA37, G = +525 sRATED OUTPUTV oltage OutputRL 2k 12 600 10 ResistanceDC, Open Loop70 Short Circuit CurrentRL = 0 2560(6)mAPOWER SUPPLYR ated Voltage 15 VDCV oltage Range,Derated Performance 4 22 VDCC urrent, QuiescentIO = RANGES pecification 40+85 COperating 40+85 CNOTES: (1) Measured with industry-standard noise test circuit (Figures 1 and 2).

5 Due to errors introduced by this method, these current noise specifications shouldbe used for comparison purposes only. (2) Offset voltage specification are measured with automatic test equipment after approximately seconds from power turn-on. (3) Unnulled or nulled with 8k to 20k potentiometer. (4) Long-term voltage offset vs time trend line does not include warm-up drift. (5) Typical specification onlyon plastic package units. Slew rate varies on all units due to differing test methods. Minimum specification applies to open-loop test. (6) This parameter specified , VOLTAGE(1)Input Offset Voltage 48 220(3) VAverage Drift(2)TA MIN to TA MAX (3) V/ CSupply Rejection VCC = to 18V VCC = to 18V90 (3)122dBBIAS CURRENTI nput Bias Current 21 150(3)nAOFFSET CURRENTI nput Offset Current20135(3)nAVOLTAGE RANGEC ommon-Mode Input Range (3) RejectionVIN = 11 VDC96(3)122dBOPEN-LOOP GAIN, DCOpen-Loop Voltage GainRL 2k 113(3)120dBRATED OUTPUTV oltage OutputRL = 2k (3) Circuit CurrentVO = 0 VDC25mATEMPERATURE RANGES pecification 40+85 CNOTES: (1) Offset voltage specification are measured with automatic test equipment after approximately from power turn-on.

6 (2) Unnulled or nulled with 8k to20k potentiometer. (3) This parameter specified by CHARACTERISTICS (Cont.)At VCC = 15V and 40 C TA +85 C, unless otherwise , CHARACTERISTICSAt TA = +25 C, VCC = 15 VDC, unless otherwise OFFSET VOLTAGE WARM-UP DRIFTTime From Power Turn-On (min)0+10+50 5 10 Offset Voltage Change ( V)123456 INPUT VOLTAGE noise vs noise BANDWIDTH( to Indicated Frequency) noise Bandwidth (Hz) noise ( Vrms)R = 0S TOTAL INPUT VOLTAGE noise SPECTRAL DENSITYvs SOURCE RESISTANCES ource Resistance ( ) 1001k10k100806010864020421 Voltage noise (nV/ Hz)-+R1R1R = 2 R1xSOURCER esistor noise Only1kHz10 HzVOLTAGE noise SPECTRAL DENSITYvs SUPPLY VOLTAGE543210 Supply Voltage (V )CC 5 10 15 20 Voltage noise (nV/ Hz)1kHz10 HzVoltage noise (nV/ Hz)VOLTAGE noise SPECTRAL DENSITYvs TEMPERATURE54321 75 50 250+25+50+75+100 +125 Ambient Temperature ( C)10Hz1kHzINPUT CURRENT noise SPECTRAL DENSITYC urrent noise (pA/ Hz)

7 This industry-standard equationis inaccurate and these figures shouldbe used for comparison purposes only!Current noise Test CircuitIn= (eno)2 (130nV)21M 100 xDUT100k 500k 500k 10k enoFrequency (Hz)Warning:OPA27, CHARACTERISTICS (Cont.)At TA = +25 C, VCC = 15 VDC, unless otherwise VOLTAGE noise SPECTRAL DENSITY1101001kFrequency (Hz)Voltage noise (nV/ Hz)1086420 OPEN-LOOP FREQUENCY RESPONSEF requency (Hz)101001k10k100k1M10M100M1401201008060 40200 Voltage Gain (dB)OPA27 OPA37 BIAS AND OFFSET CURRENT vs TEMPERATUREA mbient Temperature ( C) 75 50 250+25+50 BiasOffset+75+100 +125 Absolute Bias Current (nA)20151050 Absolute Offset Current (nA)20151050 OPA27 CLOSED-LOOP VOLTAGE GAIN ANDPHASE SHIFT vs FREQUENCY (G = 100)Frequency (Hz)101001k10k100k1M10M100 MVoltage Gain (dB)Phase Shift (degrees)50403020100 10 200 45 90 135 180 225 GainOPA37 CLOSED-LOOP VOLTAGE GAIN ANDPHASE SHIFT vs FREQUENCY (G = 100)Frequency (Hz)101001k10k100k1M10M100 MVoltage Gain (dB)Phase Shift (degrees)50403020100 10 200 45 90 135 180 225 GainG = 5 COMMON-MODE REJECTION vs FREQUENCY140120100806040200 Common-Mode Rejection (dB)

8 Frequency (Hz)1101001k10k100k1M10 MOPA37 OPA27 OPA27, CHARACTERISTICS (Cont.)At TA = +25 C, VCC = 15 VDC, unless otherwise SUPPLY REJECTION vs FREQUENCY140120100806040200 Power Supply Rejection (dB)Frequency (Hz)1101001k10k100k1M10 MOPA27 VCC+VCCOPEN-LOOP VOLTAGE GAIN vs SUPPLY VOLTAGE130125120115 Voltage Gain (dB) 5 Supply Voltage (V )CC 10 15 20 25R = 2kL R = 600L OPEN-LOOP VOLTAGE GAIN vs TEMPERATUREV oltage Gain (dB)135130125120115 Ambient Temperature ( C) 75 50 250+25+50+75+100 +125RL = 2k SUPPLY CURRENT vs SUPPLY VOLTAGE6543210 Supply Current (mA)0 Supply Voltage (V )CC 5 10 15 20+25 C+125 C 55 CCOMMON-MODE INPUT VOLTAGE RANGEvs SUPPLY VOLTAGE+15+10+50 5 10 15 Common-Mode Range (V)0 Supply Voltage (V )CC 5 10 15 20T = +25 CAT = +125 CAT = 55 CAT = +25 CAT = +125 CAT = 55 CAOPA27 SMALL SIGNAL TRANSIENT RESPONSETime ( s)+60+40+200 20 40 60 Output Voltage (mV)012A = +1C = , PERFORMANCE CURVES (Cont.)

9 At TA = +25 C, VCC = 15 VDC, unless otherwise SMALL SIGNAL TRANSIENT RESPONSETime ( s)+60+40+200 20 40 60 Output Voltage (mV) = +5C = LARGE SIGNAL TRANSIENT RESPONSETime ( s)+6+4+20 2 4 6 Output Voltage (V)246081012A = +1 VCLOPA37 LARGE SIGNAL TRANSIENT RESPONSETime ( s)+15+10+50 5 10 15 Output Voltage (V)1230456A = +5 VOPA27, INFORMATIONOFFSET VOLTAGE ADJUSTMENTThe OPA27 and OPA37 offset voltages are laser-trimmedand require no further trim for most applications. Offsetvoltage drift will not be degraded when the input offset isnulled with a 10k trim potentiometer. Other potentiometervalues from 1k to 1M can be used, but VOS drift will bedegraded by an additional V/ C to V/ C. Nullinglarge system offsets by use of the offset trim adjust willdegrade drift performance by approximately V/ C permillivolt of offset.

10 Large system offsets can be nulled withoutdrift degradation by input conventional offset voltage trim circuit is shown in Figure3. For trimming very small offsets, the higher resolutioncircuit shown in Figure 4 is OPA27 and OPA37 can replace 741-type operationalamplifiers by removing or modifying the trim POTENTIALSThe OPA27 and OPA37 are laser-trimmed to microvolt-levelinput offset voltages, and for very-low input offset layout and circuit design techniques are necessary toprevent offset and drift errors from external thermoelectricpotentials. Dissimilar metal junctions can generate smallEMFs if care is not taken to eliminate either their sources(lead-to-PC, wiring, etc.) or their temperature difference (seeFigure 11).Short, direct mounting of the OPA27 and OPA37 with closespacing of the input pins is highly recommended.