LMP2231 www.ti.com SNOSB01E–JANUARY2008–REVISEDMARCH2013 LMP2231 Single Micropower, 1.6V, Precision Operational Amplifier with CMOS Inputs CheckforSamples:LMP2231 FEATURES DESCRIPTION 1 (For V = 5V, T = 25°C, Typical Unless The LMP2231 is a single micropower precision 23 S A OtherwiseNoted) amplifier designed for battery powered applications. The 1.6V to 5.5V operating supply voltage range and • SupplyCurrent10µA quiescent power consumption of only 16 μW extend • OperatingVoltageRange1.6Vto5.5V the battery life in portable battery operated systems. • TCV (LMP2231A)±0.4µV/°C(max) The LMP2231 is part of the LMP™ precision amplifier OS family. The high impedance CMOS input makes it • TCV (LMP2231B)±2.5µV/°C(max) OS ideal for instrumentation and other sensor interface • V ±150 µV(max) applications. OS • InputBiasCurrent20fA The LMP2231 has a maximum offset of 150 µV and • PSRR120dB maximum offset voltage drift of only 0.4 µV/°C along • CMRR97dB with low bias current of only ±20 fA. These precise specifications make the LMP2231 a great choice for • OpenLoopGain120dB maintainingsystemaccuracyandlongtermstability. • GainBandwidthProduct130kHz The LMP2231 has a rail-to-rail output that swings 15 • SlewRate58V/ms mV from the supply voltage, which increases system • InputVoltageNoise,f=1kHz60nV/√Hz dynamic range. The common mode input voltage • TemperatureRange–40°Cto125°C range extends 200 mV below the negative supply, thus the LMP2231 is ideal for use in single supply applicationswithgroundsensing. APPLICATIONS The LMP2231 is offered in 5-Pin SOT-23 and 8-pin • PrecisionInstrumentationAmplifiers SOICpackages. • BatteryPoweredMedicalInstrumentation The dual and quad versions of this product are also • HighImpedanceSensors available. The dual, LMP2232 is offered in 8-pin • StrainGaugeBridgeAmplifier SOIC and VSSOP. The quad, LMP2234 is offered in • ThermocoupleAmplifiers 14-pinSOICandTSSOP. 1 Pleasebeawarethatanimportantnoticeconcerningavailability,standardwarranty,anduseincriticalapplicationsof TexasInstrumentssemiconductorproductsanddisclaimerstheretoappearsattheendofthisdatasheet. LMPisatrademarkofTexasInstruments. 2 Allothertrademarksarethepropertyoftheirrespectiveowners. 3 PRODUCTIONDATAinformationiscurrentasofpublicationdate. Copyright©2008–2013,TexasInstrumentsIncorporated Products conform to specifications per the terms of the Texas Instruments standard warranty. Production processing does not necessarilyincludetestingofallparameters.

LMP2231 SNOSB01E–JANUARY2008–REVISEDMARCH2013 www.ti.com Typical Application V+ V+ 3 2 - LMP2231 6 LM4140A + 1 PF 1,4,7,8 + V 0.1 PF + V + ½ 10 k: 40 k: 10 PF LMP2232 - 12 k: R+’R R + - V VA LMP2231 IN 1 k: R + ADC121S021 R+’R + V 12 k: - ½ GND LMP2232 10 k: 40 k: + Figure1. StrainGaugeBridgeAmplifier Thesedeviceshavelimitedbuilt-inESDprotection.Theleadsshouldbeshortedtogetherorthedeviceplacedinconductivefoam duringstorageorhandlingtopreventelectrostaticdamagetotheMOSgates. Absolute Maximum Ratings(1)(2) ESDTolerance (3) HumanBodyModel 2000V MachineModel 100V DifferentialInputVoltage ±300mV SupplyVoltage(V =V+-V–) 6V S VoltageonInput/OutputPins V++0.3V,V––0.3V StorageTemperatureRange −65°Cto150°C JunctionTemperature (4) 150°C Forsolderingspecifications:seeproductfolderatwww.ti.comandhttp://www.ti.com/lit/SNOA549. (1) AbsoluteMaximumRatingsindicatelimitsbeyondwhichdamagemayoccur.OperatingRatingsindicateconditionsforwhichthedevice isintendedtobefunctional,butspecificperformanceisnotensured.Forensuredspecificationsandtestconditions,seetheElectrical Characteristics. (2) IfMilitary/Aerospacespecifieddevicesarerequired,pleasecontacttheTISalesOffice/Distributorsforavailabilityandspecifications. (3) HumanBodyModel,applicablestd.MIL-STD-883,Method3015.7.MachineModel,applicablestd.JESD22-A115-A(ESDMMstd.of JEDEC)Field-InducedCharge-DeviceModel,applicablestd.JESD22-C101-C(ESDFICDMstd.ofJEDEC). (4) ThemaximumpowerdissipationisafunctionofT ,θ .Themaximumallowablepowerdissipationatanyambienttemperatureis J(MAX) JA P =(T –T )/θ .AllnumbersapplyforpackagessoldereddirectlyontoaPCBoard. D J(MAX) A JA 2 SubmitDocumentationFeedback Copyright©2008–2013,TexasInstrumentsIncorporated ProductFolderLinks:LMP2231

LMP2231 www.ti.com SNOSB01E–JANUARY2008–REVISEDMARCH2013 Operating Ratings(1) OperatingTemperatureRange (2) −40°Cto125°C SupplyVoltage(V =V+-V−) 1.6Vto5.5V S PackageThermalResistance(θ ) (2) 5-PinSOT-23 160.6°C/W JA 8-PinSOIC 116.2°C/W (1) AbsoluteMaximumRatingsindicatelimitsbeyondwhichdamagemayoccur.OperatingRatingsindicateconditionsforwhichthedevice isintendedtobefunctional,butspecificperformanceisnotensured.Forensuredspecificationsandtestconditions,seetheElectrical Characteristics. (2) ThemaximumpowerdissipationisafunctionofT ,θ .Themaximumallowablepowerdissipationatanyambienttemperatureis J(MAX) JA P =(T –T )/θ .AllnumbersapplyforpackagessoldereddirectlyontoaPCBoard. D J(MAX) A JA 5V DC Electrical Characteristics(1) Unlessotherwisespecified,alllimitsensuredforT =25°C,V+=5V,V−=0V,V =V =V+/2,andR >1MΩ.Boldface A CM O L limitsapplyatthetemperatureextremes. Symbol Parameter Conditions Min(2) Typ(3) Max(2) Units V InputOffsetVoltage ±10 ±150 μV OS ±230 TCV InputOffsetVoltageDrift LMP2231A ±0.3 ±0.4 μV/°C OS LMP2231B ±0.3 ±2.5 I InputBiasCurrent 0.02 ±1 BIAS pA ±50 I InputOffsetCurrent 5 fA OS CMRR CommonModeRejectionRatio 0V≤V ≤4V 81 97 CM dB 80 PSRR PowerSupplyRejectionRatio 1.6V≤V+≤5.5V 83 120 V−=0V,V =0V 83 dB CM CMRR≥80dB −0.2 4.2 CMVR CommonModeVoltageRange V CMRR≥79dB −0.2 4.2 V =0.3Vto4.7V 110 AVOL LargeSignalVoltageGain RO=10kΩtoV+/2 108 120 dB L V OutputSwingHigh R =10kΩtoV+/2 17 50 mV O L V (diff)=100mV 50 fromeither IN OutputSwingLow R =10kΩtoV+/2 17 50 rail L V (diff)=−100mV 50 IN I OutputCurrent (4) Sourcing,V toV– 27 30 mA O O V (diff)=100mV 19 IN Sinking,V toV+ 17 22 O V (diff)=−100mV 12 IN I SupplyCurrent 10 16 S µA 18 (1) ElectricalTablevaluesapplyonlyforfactorytestingconditionsatthetemperatureindicated.Factorytestingconditionsresultinvery limitedself-heatingofthedevicesuchthatT =T .Noensuredspecificationofparametricperformanceisindicatedintheelectrical J A tablesunderconditionsofinternalself-heatingwhereT >T .AbsoluteMaximumRatingsindicatejunctiontemperaturelimitsbeyond J A whichthedevicemaybepermanentlydegraded,eithermechanicallyorelectrically. (2) Alllimitsarespecifiedbytesting,statisticalanalysisordesign. (3) Typicalvaluesrepresentthemostlikelyparametricnormatthetimeofcharacterization.Actualtypicalvaluesmayvaryovertimeand willalsodependontheapplicationandconfiguration.Thetypicalvaluesarenottestedandarenotensuredonshippedproduction material. (4) Theshortcircuittestisamomentaryopenlooptest. Copyright©2008–2013,TexasInstrumentsIncorporated SubmitDocumentationFeedback 3 ProductFolderLinks:LMP2231

LMP2231 SNOSB01E–JANUARY2008–REVISEDMARCH2013 www.ti.com 5V AC Electrical Characteristics(1) Unlessotherwisespecified,alllimitsensuredforT =25°C,V+=5V,V−=0V,V =V =V+/2,andR >1MΩ.Boldface A CM O L limitsapplyatthetemperatureextremes. Symbol Parameter Conditions Min(2) Typ(3) Max(2) Units GBW Gain-BandwidthProduct C =20pF,R =10kΩ 130 kHz L L SR SlewRate A =+1 FallingEdge 33 58 V 32 V/ms RisingEdge 33 48 32 θ PhaseMargin C =20pF,R =10kΩ 78 deg m L L G GainMargin C =20pF,R =10kΩ 27 dB m L L e Input-ReferredVoltageNoiseDensity f=1kHz 60 nV/√Hz n Input-ReferredVoltageNoise 0.1Hzto10Hz 2.3 μV PP i Input-ReferredCurrentNoise f=1kHz 10 fA/√Hz n THD+N TotalHarmonicDistortion+Noise f=100Hz,R =10kΩ 0.002 % L (1) ElectricalTablevaluesapplyonlyforfactorytestingconditionsatthetemperatureindicated.Factorytestingconditionsresultinvery limitedself-heatingofthedevicesuchthatT =T .Noensuredspecificationofparametricperformanceisindicatedintheelectrical J A tablesunderconditionsofinternalself-heatingwhereT >T .AbsoluteMaximumRatingsindicatejunctiontemperaturelimitsbeyond J A whichthedevicemaybepermanentlydegraded,eithermechanicallyorelectrically. (2) Alllimitsarespecifiedbytesting,statisticalanalysisordesign. (3) Typicalvaluesrepresentthemostlikelyparametricnormatthetimeofcharacterization.Actualtypicalvaluesmayvaryovertimeand willalsodependontheapplicationandconfiguration.Thetypicalvaluesarenottestedandarenotensuredonshippedproduction material. 3.3V DC Electrical Characteristics(1) Unlessotherwisespecified,alllimitsensuredforT =25°C,V+=3.3V,V−=0V,V =V =V+/2,andR >1MΩ.Boldface A CM O L limitsapplyatthetemperatureextremes. Symbol Parameter Conditions Min(2) Typ(3) Max(2) Units V InputOffsetVoltage ±10 ±160 μV OS ±250 TCV InputOffsetVoltageDrift LMP2231A ±0.3 ±0.4 μV/°C OS LMP2231B ±0.3 ±2.5 I InputBiasCurrent 0.02 ±1 BIAS pA ±50 I InputOffsetCurrent 5 fA OS CMRR CommonModeRejectionRatio 0V≤V ≤2.3V 79 92 CM dB 77 PSRR PowerSupplyRejectionRatio 1.6V≤V+≤5.5V 83 120 V−=0V,V =0V 83 dB CM CMRR≥78dB −0.2 2.5 CMVR CommonModeVoltageRange V CMRR≥77dB −0.2 2.5 V =0.3Vto3V 108 AVOL LargeSignalVoltageGain RO=10kΩtoV+/2 107 120 dB L V OutputSwingHigh R =10kΩtoV+/2 14 50 mV O L V (diff)=100mV 50 fromeither IN OutputSwingLow R =10kΩtoV+/2 50 rail L 14 V (diff)=−100mV 50 IN (1) ElectricalTablevaluesapplyonlyforfactorytestingconditionsatthetemperatureindicated.Factorytestingconditionsresultinvery limitedself-heatingofthedevicesuchthatT =T .Noensuredspecificationofparametricperformanceisindicatedintheelectrical J A tablesunderconditionsofinternalself-heatingwhereT >T .AbsoluteMaximumRatingsindicatejunctiontemperaturelimitsbeyond J A whichthedevicemaybepermanentlydegraded,eithermechanicallyorelectrically. (2) Alllimitsarespecifiedbytesting,statisticalanalysisordesign. (3) Typicalvaluesrepresentthemostlikelyparametricnormatthetimeofcharacterization.Actualtypicalvaluesmayvaryovertimeand willalsodependontheapplicationandconfiguration.Thetypicalvaluesarenottestedandarenotensuredonshippedproduction material. 4 SubmitDocumentationFeedback Copyright©2008–2013,TexasInstrumentsIncorporated ProductFolderLinks:LMP2231

LMP2231 www.ti.com SNOSB01E–JANUARY2008–REVISEDMARCH2013 3.3V DC Electrical Characteristics(1) (continued) Unlessotherwisespecified,alllimitsensuredforT =25°C,V+=3.3V,V−=0V,V =V =V+/2,andR >1MΩ.Boldface A CM O L limitsapplyatthetemperatureextremes. Symbol Parameter Conditions Min(2) Typ(3) Max(2) Units I OutputCurrent (4) Sourcing,V toV– 11 14 mA O O V (diff)=100mV 8 IN Sinking,V toV+ 8 11 O V (diff)=−100mV 5 IN I SupplyCurrent 10 15 S µA 16 (4) Theshortcircuittestisamomentaryopenlooptest. 3.3V AC Electrical Characteristics(1) Unlessotherwiseisspecified,alllimitsensuredforT =25°C,V+=3.3V,V−=0V,V =V =V+/2,andR >1MΩ.Boldface A CM O L limitsapplyatthetemperatureextremes. Symbol Parameter Conditions Min(2) Typ(3) Max(2) Units GBW Gain-BandwidthProduct C =20pF,R =10kΩ 128 kHz L L SR SlewRate A =+1,C =20pF FallingEdge 58 V L R =10kΩ V/ms L RisingEdge 48 θ PhaseMargin C =20pF,R =10kΩ 76 deg m L L G GainMargin C =20pF,R =10kΩ 26 dB m L L e Input-ReferredVoltageNoiseDensity f=1kHz 60 nV/√Hz n Input-ReferredVoltageNoise 0.1Hzto10Hz 2.4 μV PP i Input-ReferredCurrentNoise f=1kHz 10 fA/√Hz n THD+N TotalHarmonicDistortion+Noise f=100Hz,R =10kΩ 0.003 % L (1) ElectricalTablevaluesapplyonlyforfactorytestingconditionsatthetemperatureindicated.Factorytestingconditionsresultinvery limitedself-heatingofthedevicesuchthatT =T .Noensuredspecificationofparametricperformanceisindicatedintheelectrical J A tablesunderconditionsofinternalself-heatingwhereT >T .AbsoluteMaximumRatingsindicatejunctiontemperaturelimitsbeyond J A whichthedevicemaybepermanentlydegraded,eithermechanicallyorelectrically. (2) Alllimitsarespecifiedbytesting,statisticalanalysisordesign. (3) Typicalvaluesrepresentthemostlikelyparametricnormatthetimeofcharacterization.Actualtypicalvaluesmayvaryovertimeand willalsodependontheapplicationandconfiguration.Thetypicalvaluesarenottestedandarenotensuredonshippedproduction material. 2.5V DC Electrical Characteristics(1) Unlessotherwisespecified,alllimitsensuredforT =25°C,V+=2.5V,V−=0V,V =V =V+/2,andR >1MΩ.Boldface A CM O L limitsapplyatthetemperatureextremes. Symbol Parameter Conditions Min(2) Typ(3) Max(2) Units V InputOffsetVoltage ±10 ±190 OS μV ±275 TCV InputOffsetVoltageDrift LMP2231A ±0.3 ±0.4 OS μV/°C LMP2231B ±0.3 ±2.5 I InputBiasCurrent 0.02 ±1.0 BIAS pA ±50 I InputOffsetCurrent 5 fA OS CMRR CommonModeRejectionRatio 0V≤V ≤1.5V 77 91 CM dB 76 (1) ElectricalTablevaluesapplyonlyforfactorytestingconditionsatthetemperatureindicated.Factorytestingconditionsresultinvery limitedself-heatingofthedevicesuchthatT =T .Noensuredspecificationofparametricperformanceisindicatedintheelectrical J A tablesunderconditionsofinternalself-heatingwhereT >T .AbsoluteMaximumRatingsindicatejunctiontemperaturelimitsbeyond J A whichthedevicemaybepermanentlydegraded,eithermechanicallyorelectrically. (2) Alllimitsarespecifiedbytesting,statisticalanalysisordesign. (3) Typicalvaluesrepresentthemostlikelyparametricnormatthetimeofcharacterization.Actualtypicalvaluesmayvaryovertimeand willalsodependontheapplicationandconfiguration.Thetypicalvaluesarenottestedandarenotensuredonshippedproduction material. Copyright©2008–2013,TexasInstrumentsIncorporated SubmitDocumentationFeedback 5 ProductFolderLinks:LMP2231

LMP2231 SNOSB01E–JANUARY2008–REVISEDMARCH2013 www.ti.com 2.5V DC Electrical Characteristics(1) (continued) Unlessotherwisespecified,alllimitsensuredforT =25°C,V+=2.5V,V−=0V,V =V =V+/2,andR >1MΩ.Boldface A CM O L limitsapplyatthetemperatureextremes. Symbol Parameter Conditions Min(2) Typ(3) Max(2) Units PSRR PowerSupplyRejectionRatio 1.6V≤V+≤5.5V 83 120 V−=0V,V =0V 83 dB CM CMVR CommonModeVoltageRange CMRR≥77dB −0.2 1.7 V CMRR≥76dB −0.2 1.7 A LargeSignalVoltageGain V =0.3Vto2.2V 104 120 VOL RO=10kΩtoV+/2 104 dB L V OutputSwingHigh R =10kΩtoV+/2 12 50 O L V (diff)=100mV 50 mV IN fromeither OutputSwingLow RL=10kΩtoV+/2 13 50 rail V (diff)=−100mV 50 IN I OutputCurrent (4) Sourcing,V toV− 5 8 O O V (diff)=100mV 4 IN mA Sinking,V toV+ 3.5 7 O V (diff)=−100mV 2.5 IN I SupplyCurrent 10 14 S µA 15 (4) Theshortcircuittestisamomentaryopenlooptest. 2.5V AC Electrical Characteristics(1) Unlessotherwisespecified,alllimitsensuredforT =25°C,V+=2.5V,V−=0V,V =V =V+/2,andR >1MΩ.Boldface A CM O L limitsapplyatthetemperatureextremes. Symbol Parameter Conditions Min(2) Typ(3) Max(2) Units GBW Gain-BandwidthProduct C =20pF,R =10kΩ 128 kHz L L SR SlewRate A =+1,C =20pF FallingEdge 58 V L R =10kΩ V/ms L RisingEdge 48 θ PhaseMargin C =20pF,R =10kΩ 74 deg m L L G GainMargin C =20pF,R =10kΩ 26 dB m L L e Input-ReferredVoltageNoiseDensity f=1kHz 60 nV/√Hz n Input-ReferredVoltageNoise 0.1Hzto10Hz 2.5 μV PP i Input-ReferredCurrentNoise f=1kHz 10 fA/√Hz n THD+N TotalHarmonicDistortion+Noise f=100Hz,R =10kΩ 0.005 % L (1) ElectricalTablevaluesapplyonlyforfactorytestingconditionsatthetemperatureindicated.Factorytestingconditionsresultinvery limitedself-heatingofthedevicesuchthatT =T .Noensuredspecificationofparametricperformanceisindicatedintheelectrical J A tablesunderconditionsofinternalself-heatingwhereT >T .AbsoluteMaximumRatingsindicatejunctiontemperaturelimitsbeyond J A whichthedevicemaybepermanentlydegraded,eithermechanicallyorelectrically. (2) Alllimitsarespecifiedbytesting,statisticalanalysisordesign. (3) Typicalvaluesrepresentthemostlikelyparametricnormatthetimeofcharacterization.Actualtypicalvaluesmayvaryovertimeand willalsodependontheapplicationandconfiguration.Thetypicalvaluesarenottestedandarenotensuredonshippedproduction material. 6 SubmitDocumentationFeedback Copyright©2008–2013,TexasInstrumentsIncorporated ProductFolderLinks:LMP2231

LMP2231 www.ti.com SNOSB01E–JANUARY2008–REVISEDMARCH2013 1.8V DC Electrical Characteristics (1) Unlessotherwisespecified,alllimitsensuredforT =25°C,V+=1.8V,V−=0V,V =V =V+/2,andR >1MΩ.Boldface A CM O L limitsapplyatthetemperatureextremes. Symbol Parameter Conditions Min(2) Typ(3) Max(2) Units V InputOffsetVoltage ±10 ±230 OS μV ±325 TCV InputOffsetVoltageDrift LMP2231A ±0.3 ±0.4 OS μV/°C LMP2231B ±0.3 ±2.5 I InputBiasCurrent 0.02 ±1.0 BIAS pA ±50 I InputOffsetCurrent 5 fA OS CMRR CommonModeRejectionRatio 0V≤V ≤0.8V 76 92 CM dB 75 PSRR PowerSupplyRejectionRatio 1.6V≤V+≤5.5V 83 120 V−=0V,V =0V 83 dB CM CMRR≥76dB −0.2 1.0 CMVR CommonModeVoltageRang V CMRR≥75dB 0 1.0 V =0.3Vto1.5V 103 AVOL LargeSignalVoltageGain RO=10kΩtoV+/2 103 120 dB L V OutputSwingHigh R =10kΩtoV+/2 12 50 O L V (diff)=100mV 50 mV IN fromeither OutputSwingLow RL=10kΩtoV+/2 13 50 rail V (diff)=−100mV 50 IN I OutputCurrent (4) Sourcing,V toV− 2.5 5 O O V (diff)=100mV 2 IN mA Sinking,V toV+ 2 5 O V (diff)=−100mV 1.5 IN I SupplyCurrent 10 14 S µA 15 (1) ElectricalTablevaluesapplyonlyforfactorytestingconditionsatthetemperatureindicated.Factorytestingconditionsresultinvery limitedself-heatingofthedevicesuchthatT =T .Noensuredspecificationofparametricperformanceisindicatedintheelectrical J A tablesunderconditionsofinternalself-heatingwhereT >T .AbsoluteMaximumRatingsindicatejunctiontemperaturelimitsbeyond J A whichthedevicemaybepermanentlydegraded,eithermechanicallyorelectrically. (2) Alllimitsarespecifiedbytesting,statisticalanalysisordesign. (3) Typicalvaluesrepresentthemostlikelyparametricnormatthetimeofcharacterization.Actualtypicalvaluesmayvaryovertimeand willalsodependontheapplicationandconfiguration.Thetypicalvaluesarenottestedandarenotensuredonshippedproduction material. (4) Theshortcircuittestisamomentaryopenlooptest. 1.8V AC Electrical Characteristics(1) Unlessotherwiseisspecified,alllimitsensuredforT =25°C,V+=1.8V,V−=0V,V =V =V+/2,andR >1MΩ.Boldface A CM O L limitsapplyatthetemperatureextremes. Symbol Parameter Conditions Min(2) Typ(3) Max(2) Units GBW Gain-BandwidthProduct C =20pF,R =10kΩ 127 kHz L L SR SlewRate A =+1,C =20pF FallingEdge 58 V L R =10kΩ V/ms L RisingEdge 48 θ PhaseMargin C =20pF,R =10kΩ 70 deg m L L G GainMargin C =20pF,R =10kΩ 25 dB m L L e Input-ReferredVoltageNoiseDensity f=1kHz 60 nV/√Hz n Input-ReferredVoltageNoise 0.1Hzto10Hz 2.4 μV PP (1) ElectricalTablevaluesapplyonlyforfactorytestingconditionsatthetemperatureindicated.Factorytestingconditionsresultinvery limitedself-heatingofthedevicesuchthatT =T .Noensuredspecificationofparametricperformanceisindicatedintheelectrical J A tablesunderconditionsofinternalself-heatingwhereT >T .AbsoluteMaximumRatingsindicatejunctiontemperaturelimitsbeyond J A whichthedevicemaybepermanentlydegraded,eithermechanicallyorelectrically. (2) Alllimitsarespecifiedbytesting,statisticalanalysisordesign. (3) Typicalvaluesrepresentthemostlikelyparametricnormatthetimeofcharacterization.Actualtypicalvaluesmayvaryovertimeand willalsodependontheapplicationandconfiguration.Thetypicalvaluesarenottestedandarenotensuredonshippedproduction material. Copyright©2008–2013,TexasInstrumentsIncorporated SubmitDocumentationFeedback 7 ProductFolderLinks:LMP2231

LMP2231 SNOSB01E–JANUARY2008–REVISEDMARCH2013 www.ti.com 1.8V AC Electrical Characteristics(1) (continued) Unlessotherwiseisspecified,alllimitsensuredforT =25°C,V+=1.8V,V−=0V,V =V =V+/2,andR >1MΩ.Boldface A CM O L limitsapplyatthetemperatureextremes. Symbol Parameter Conditions Min(2) Typ(3) Max(2) Units i Input-ReferredCurrentNoise f=1kHz 10 fA/√Hz n THD+N TotalHarmonicDistortion+Noise f=100Hz,R =10kΩ 0.005 % L Connection Diagram OUT 1 5 V+ N/C 1 8 N/C - 2 VIN- 2 - 7 V+ V + - VIN+ 3 + 6 VOUT 3 4 IN+ IN- V- 4 5 N/C Figure2.5-PinSOT-23(TopView) Figure3.8-PinSOIC(TopView) SeePackageNumberDBV0005A SeePackageNumberD0008A 8 SubmitDocumentationFeedback Copyright©2008–2013,TexasInstrumentsIncorporated ProductFolderLinks:LMP2231

LMP2231 www.ti.com SNOSB01E–JANUARY2008–REVISEDMARCH2013 Typical Performance Characteristics UnlessotherwiseSpecified:T =25°C,V =5V,V =V /2,whereV =V+-V− A S CM S S OffsetVoltageDistribution TCV Distribution OS 16 10 VS = 5V VS = 5V 14 TA = 25°C VCM = VS/2 12 VCM = VS/2 8 -40°C d(cid:3)TA d(cid:3)125°C )% )% ( E 10 ( E 6 G G A A T 8 T N N E E C C 4 R 6 R E E P P 4 2 2 0 0 -150 -100 -50 0 50 100 150 -2.5 -2 -1.5 -1 -0.5 0 0.5 1 1.5 2 2.5 VOS (PV) TCVOS (PV/°C) Figure4. Figure5. OffsetVoltageDistribution TCV Distribution OS 14 10 VS = 3.3V -40°C d(cid:3)TA d(cid:3)125°C 12 TA = 25°C VS = 3.3V VCM = VS/2 8 VCM = VS/2 )% 10 )% ( E ( E 6 G 8 G A A TN TN EC 6 EC 4 R R E E P 4 P 2 2 0 0 -150 -100 -50 0 50 100 150 -2.5 -2 -1.5 -1 -0.5 0 0.5 1 1.5 2 2.5 VOS (PV) TCVOS (PV/°C) Figure6. Figure7. OffsetVoltageDistribution TCV Distribution OS 14 10 VS = 2.5V VS = 2.5V 12 TA = 25°C VCM = VS/2 VCM = VS/2 8 -40°C d(cid:3)TA d(cid:3)125°C )% 10 )% ( E ( E 6 G 8 G A A TN TN EC 6 EC 4 R R E E P 4 P 2 2 0 0 -150 -100 -50 0 50 100 150 -2.5 -2 -1.5 -1 -0.5 0 0.5 1 1.5 2 2.5 VOS (PV) TCVOS (PV/°C) Figure8. Figure9. Copyright©2008–2013,TexasInstrumentsIncorporated SubmitDocumentationFeedback 9 ProductFolderLinks:LMP2231

LMP2231 SNOSB01E–JANUARY2008–REVISEDMARCH2013 www.ti.com Typical Performance Characteristics (continued) UnlessotherwiseSpecified:T =25°C,V =5V,V =V /2,whereV =V+-V− A S CM S S OffsetVoltageDistribution TCV Distribution OS 12 25 VS = 1.8V VS = 1.8V 10 TA = 25°C VCM = VS/2 VCM = VS/2 20 -40°C d(cid:3)TA d(cid:3)125°C )% 8 )% ( E ( E 15 G G A A T 6 T N N E E C C 10 RE 4 RE P P 5 2 0 0 -150 -100 -50 0 50 100 150 -2.5 -2 -1.5 -1 -0.5 0 0.5 1 1.5 2 2.5 VOS (PV) TCVOS (PV/°C) Figure10. Figure11. OffsetVoltagevs. OffsetVoltagevs. V V CM CM 250 250 VS = 5V VS = 3.3V -40°C 150 150 )VP 25°C -40°C ( E 25°C GA 50 85°C )V 50 85°C T P LO 125°C ( S V O 125°C T -50 V -50 E S F F O -150 -150 -250 -250 -0.2 0.8 1.8 2.8 3.8 4.3 -0.2 0.2 0.6 1 1.4 1.8 2.2 2.6 3 VCM (V) VCM (V) Figure12. Figure13. OffsetVoltagevs. OffsetVoltagevs. V V CM CM 250 250 VS = 2.5V VS = 1.8V 150 150 -40°C 25°C -40°C 85°C 25°C )V 50 )V 50 P P ( S ( S 85°C O O V -50 V -50 125°C 125°C -150 -150 -250 -250 -0.2 0.2 0.6 1 1.4 1.8 2.2 -0.2 0 0.2 0.4 0.6 0.8 1 1.2 1.4 VCM (V) VCM (V) Figure14. Figure15. 10 SubmitDocumentationFeedback Copyright©2008–2013,TexasInstrumentsIncorporated ProductFolderLinks:LMP2231

LMP2231 www.ti.com SNOSB01E–JANUARY2008–REVISEDMARCH2013 Typical Performance Characteristics (continued) UnlessotherwiseSpecified:T =25°C,V =5V,V =V /2,whereV =V+-V− A S CM S S OffsetVoltagevs. OffsetVoltagevs. Temperature SupplyVoltage 120 100 100 VS = 1.8V, 2.5V, 3.3V, 5V VCM = 0V 5 TYPICAL PARTS 80 80 OFFSET VOLTAGE (V)P --22464000000 )V( EGATLOPV TESFFO 2460000 -40°C 25°C 85°C -20 -60 125°C -80 -40 -40 -20 0 20 40 60 80 100 120 1.5 2 2.5 3 3.5 4 4.5 5 5.5 TEMPERATURE (°C) SUPPLY VOLTAGE (V) Figure16. Figure17. TimeDomainVoltageNoise TimeDomainVoltageNoise Figure18. Figure19. TimeDomainVoltageNoise TimeDomainVoltageNoise Figure20. Figure21. Copyright©2008–2013,TexasInstrumentsIncorporated SubmitDocumentationFeedback 11 ProductFolderLinks:LMP2231

LMP2231 SNOSB01E–JANUARY2008–REVISEDMARCH2013 www.ti.com Typical Performance Characteristics (continued) UnlessotherwiseSpecified:T =25°C,V =5V,V =V /2,whereV =V+-V− A S CM S S InputBiasCurrentvs. InputBiasCurrentvs. V V CM CM 40 10 VS = 2V 8 VS = 2V 30 )Af( T 20 25°C )Ap( T 46 NER 10 NER 2 85°C R R UC 0 UC 0 S -40°C S A A -2 IB -10 IB T T -4 125°C UP -20 UP N N -6 I I -30 -8 -40 -10 0 0.25 0.5 0.75 1 1.25 1.5 0 0.25 0.5 0.75 1 1.25 1.5 VCM (V) VCM (V) Figure22. Figure23. InputBiasCurrentvs. InputBiasCurrentvs. V V CM CM 40 10 30 VS = 2.5V 8 VS = 2.5V )A )A 6 f( TN 20 -40°C p( TN 4 E 10 E 85°C R R 2 R R UC 0 UC 0 S S AIB -10 AIB -2 TUP -20 25°C TUP -4 125°C N N -6 I I -30 -8 -40 -10 0 0.5 1 1.5 2 0 0.5 1 1.5 2 VCM (V) VCM (V) Figure24. Figure25. InputBiasCurrentvs. InputBiasCurrentvs. V V CM CM 100 20 VS = 3.3V VS = 3.3V 75 15 )A )A f( T 50 25°C p( T 10 125°C N N E 25 E 5 R R R R U U C 0 C 0 S S AIB -25 -40°C AIB -5 85°C T T UP -50 UP -10 N N I I -75 -15 -100 -20 0 0.5 1 1.5 2 2.5 0 0.5 1 1.5 2 2.5 VCM (V) VCM (V) Figure26. Figure27. 12 SubmitDocumentationFeedback Copyright©2008–2013,TexasInstrumentsIncorporated ProductFolderLinks:LMP2231

LMP2231 www.ti.com SNOSB01E–JANUARY2008–REVISEDMARCH2013 Typical Performance Characteristics (continued) UnlessotherwiseSpecified:T =25°C,V =5V,V =V /2,whereV =V+-V− A S CM S S InputBiasCurrentvs. InputBiasCurrentvs. V V CM CM 600 30 VS = 5V 25 VS = 5V 500 400 A) 20 T (fA) 300 NT (p 1105 125°C N E RE 200 RR 5 UR 25°C CU 0 S C 100 AS -5 85°C BIA 0 T BI -10 UT -100 PU -15 NP -40°C IN -20 I -200 -25 -300 -30 0 1 2 3 4 0 1 2 3 4 VCM (V) VCM (V) Figure28. Figure29. PSRRvs. SupplyCurrentvs. Frequency SupplyVoltage 0 11 VS = 2V, 2.5V, 3.3V, 5V -20 10 125°C -40 +PSRR )AP 85°C ( T 9 )B -60 NE d R ( RRSP -1-0800 VS = 2V -PSRR RUC Y 8 -40°C 25°C LP 7 P -120 U S 6 -140 VS = 5V -160 5 10 100 1k 10k 100k 1.5 2.5 3.5 4.5 5.5 FREQUENCY (Hz) SUPPLY VOLTAGE (V) Figure30. Figure31. Copyright©2008–2013,TexasInstrumentsIncorporated SubmitDocumentationFeedback 13 ProductFolderLinks:LMP2231

LMP2231 SNOSB01E–JANUARY2008–REVISEDMARCH2013 www.ti.com Typical Performance Characteristics (continued) UnlessotherwiseSpecified:T =25°C,V =5V,V =V /2,whereV =V+-V− A S CM S S SinkingCurrentvs. SourcingCurrentvs. SupplyVoltage SupplyVoltage 30 40 35 25 -40°C 30 -40°C 20 )A 25 )Am( IKNIS 1105 85°C25°C m( IECRUOS 1250 85°C 25°C 125°C 125°C 10 5 5 0 0 1.5 2.5 3.5 4.5 5.5 1.5 2.5 3.5 4.5 5.5 SUPPLY VOLTAGE (V) SUPPLY VOLTAGE (V) Figure32. Figure33. OutputSwingHighvs. OutputSwingLowvs. SupplyVoltage SupplyVoltage 25 30 RL = 10 k: RL = 10 k: 125°C 25 )V 125°C )V m m 85°C ( L 20 ( L IA 85°C IA 20 R R M M O 25°C O R R 15 F F T 15 T U U O O V V 10 25°C -40°C -40°C 10 5 1.5 2.5 3.5 4.5 5.5 1.5 2.5 3.5 4.5 5.5 SUPPLY VOLTAGE (V) SUPPLY VOLTAGE (V) Figure34. Figure35. OpenLoopFrequencyResponse OpenLoopFrequencyResponse 100 120 100 120 PHASE -40°C PHASE 75 25°C 90 75 90 85°C )Bd( NIAG 2550 GAIN 1-4205°°CC 3600 )°( ESAHP )Bd( NIAG 2550 GAIN 3600 )(° ESAHP 25°C 0 VS = 5V 125°C 0 0 VS = 1.8V, 2.5V, 3.3V, 5V 0 RL = 10 k: RL = 10 k:, 100 k:, 10 M: CL = 20 pF 85°C CL = 20 pF, 50 pF, 100 pF -25 -30 -25 -30 10 100 1k 10k 100k 1M 10 100 1k 10k 100k 1M FREQUENCY (Hz) FREQUENCY (Hz) Figure36. Figure37. 14 SubmitDocumentationFeedback Copyright©2008–2013,TexasInstrumentsIncorporated ProductFolderLinks:LMP2231

LMP2231 www.ti.com SNOSB01E–JANUARY2008–REVISEDMARCH2013 Typical Performance Characteristics (continued) UnlessotherwiseSpecified:T =25°C,V =5V,V =V /2,whereV =V+-V− A S CM S S PhaseMarginvs. SlewRatevs. CapacitiveLoad SupplyVoltage 90 60 VS = 5V RL = 100 k: 56 FALLING EDGE 80 )°( NIGR VS = 2.5V VS = 1.8V )sm/V( E 52 A 70 T M A ES R W 48 A E H L RISING EDGE P 60 S VS = 3.3V RL = 10 k: 44 50 40 20 40 60 80 100 1.5 2 2.5 3 3.5 4 4.5 5 5.5 CAPACITIVE LOAD (pF) SUPPLY VOLTAGE (V) Figure38. Figure39. THD+Nvs. THD+Nvs. Amplitude Frequency 10 1 RL = 10 k: CL = 20 pF 1 0.1 VO = VS – 1V )%( N+D 0.1 VS = 2V VS = 2.5V )%( N+D 0.01 VS = 2.5V VS = 2V H H T T 0.01 RL = 10 k: VS = 3.3V VS = 5V 0.001 VS = 3.3V VS = 5V CL = 20 pF f = 1 kHz 0.001 0.0001 0.01 0.1 1 10 1 10 100 1k 10k 100k VOUT (VPP) FREQUENCY (Hz) Figure40. Figure41. LargeSignalStepResponse SmallSignalStepResponse VID/Vm VVSIN = = 5 2V VPP VID/Vm VVSIN = = 5 2V00 mVPP 005 f = 1 kHz 05 f = 1 kHz AV = +1 AV = +1 RL = 10 k: RL = 10 k: CL = 20 pF CL = 20 pF 100 Ps/DIV 100 Ps/DIV Figure42. Figure43. Copyright©2008–2013,TexasInstrumentsIncorporated SubmitDocumentationFeedback 15 ProductFolderLinks:LMP2231

LMP2231 SNOSB01E–JANUARY2008–REVISEDMARCH2013 www.ti.com Typical Performance Characteristics (continued) UnlessotherwiseSpecified:T =25°C,V =5V,V =V /2,whereV =V+-V− A S CM S S LargeSignalStepResponse SmallSignalStepResponse V V VS = 5V ID VS = 5V ID/V1 Vf =IN 1 = k 4H0z0 mVPP /Vm 00 Vf =IN 1 = k 5H0z mVPP 1 AV = +10 AV = +10 RL = 10 k: RL = 10 k: CL = 20 pF CL = 20 pF 100 Ps/DIV 100 Ps/DIV Figure44. Figure45. CMRR InputVoltageNoise vs. vs. Frequency Frequency 140 1000 VS = 2.5V VS = 5V 120 VS = 3.3V z) 100 H 100 )Bd( R 80 VS = 5V /Vn ES R IO M 60 N C E G 10 40 A T L O 20 V 0 1 10 100 1k 10k 100k 1 10 100 1k 10k FREQUENCY (Hz) FREQUENCY (Hz) Figure46. Figure47. 16 SubmitDocumentationFeedback Copyright©2008–2013,TexasInstrumentsIncorporated ProductFolderLinks:LMP2231

LMP2231 www.ti.com SNOSB01E–JANUARY2008–REVISEDMARCH2013 APPLICATION INFORMATION LMP2231 The LMP2231 is a single CMOS precision amplifier that offer low offset voltage and low offset voltage drift, and highgainwhileonlyconsuming10μAofcurrentperchannel. The LMP2231 is a micropower op amp, consuming only 10 μA of current. Micropower op amps extend the run time of battery powered systems and reduce energy consumption in energy limited systems. The ensured supply voltagerangeof1.8Vto5.0Valongwiththeultra-lowsupplycurrentextendthebatteryruntimeintwoways.The extended ensured power supply voltage range of 1.8V to 5.0V enables the op amp to function when the battery voltage has depleted from its nominal value down to 1.8V. In addition, the lower power consumption increases thelifeofthebattery. The LMP2231 has an input referred offset voltage of only ±150 μV maximum at room temperature. This offset is ensuredtobelessthan±230 μVovertemperature.ThisminimaloffsetvoltagealongwithverylowTCV ofonly OS 0.3µV/°Ctypicalallowsmoreaccuratesignaldetectionandamplificationinprecisionapplications. The low input bias current of only ±20 fA gives the LMP2231 superiority for use in high impedance sensor applications. Bias Current of an amplifier flows through source resistance of the sensor and the voltage resulting from this current flow appears as a noise voltage on the input of the amplifier. The low input bias current enables the LMP2231 to interface with high impedance sensors while generating negligible voltage noise. Thus the LMP2231 provides better signal fidelity and a higher signal-to-noise ration when interfacing with high impedance sensors. Texas Instruments is heavily committed to precision amplifiers and the market segment they serve. Technical support and extensive characterization data is available for sensitive applications or applications with a constrainederrorbudget. The operating supply voltage range of 1.8V to 5.5V over the extensive temperature range of −40°C to 125°C makes the LMP2231 an excellent choice for low voltage precision applications with extensive temperature requirements. The LMP2231 is offered in the space saving 5-Pin SOT-23 and 8-pin SOIC package. These small packages are idealsolutionsforareaconstrainedPCboardsandportableelectronics. TOTAL NOISE CONTRIBUTION The LMP2231 has a very low input bias current, very low input current noise, and low input voltage noise for micropower amplifier. As a result, this amplifier makes a great choice for circuits with high impedance sensor applications. Figure48showsthetypicalinputnoiseoftheLMP2231asafunctionofsourceresistancewhere: e denotestheinputreferredvoltagenoise n e isthevoltagedropacrosssourceresistanceduetoinputreferredcurrentnoiseore =R *i i i S n e showsthethermalnoiseofthesourceresistance t e showsthetotalnoiseontheinput. ni Where: eni = en2 +e2i +et2 The input current noise of the LMP2231 is so low that it will not become the dominant factor in the total noise unless source resistance exceeds 300 MΩ, which is an unrealistically high value. As is evident in Figure 48, at lower R values, total noise is dominated by the amplifier’s input voltage noise. Once R is larger than a 100 kΩ, S S then the dominant noise factor becomes the thermal noise of R . As mentioned before, the current noise will not S bethedominantnoisefactorforanypracticalapplication. Copyright©2008–2013,TexasInstrumentsIncorporated SubmitDocumentationFeedback 17 ProductFolderLinks:LMP2231

LMP2231 SNOSB01E–JANUARY2008–REVISEDMARCH2013 www.ti.com 1000 Hz) en eni /Vn 100 ( Y T ISN et ED 10 ES ei IO N E 1 G A T L O V 0.1 10 100 1k 10k 100k 1M 10M RS (:) Figure48. TotalInputNoise VOLTAGE NOISE REDUCTION The LMP2231 has an input voltage noise of 60 nV/√Hz . While this value is very low for micropower amplifiers, thisinputvoltagenoisecanbefurtherreducedbyplacingNamplifiersinparallelasshowninFigure49.Thetotal voltage noise on the output of this circuit is divided by the square root of the number of amplifiers used in this parallel combination. This is because each individual amplifier acts as an independent noise source, and the average noise of independent sources is the quadrature sum of the independent sources divided by the number ofsources.ForNidenticalamplifiers,thismeans: (cid:17)(cid:17)(cid:17)(cid:17) REDUCED INPUT VOLTAGE NOISE = N1 en21+e2n2+ +e2nN = N1 Ne2n = NN en 1 = en N Figure 49 shows a schematic of this input voltage noise reduction circuit. Typical resistor values are: R = 10Ω, G R =1kΩ,andR =1kΩ. F O 18 SubmitDocumentationFeedback Copyright©2008–2013,TexasInstrumentsIncorporated ProductFolderLinks:LMP2231

LMP2231 www.ti.com SNOSB01E–JANUARY2008–REVISEDMARCH2013 + V VIN + - VOUT RO RG V- RF + V + - RO RG V- RF + V + - RO RG V- RF + V + - RO RG V- RF Figure49. NoiseReductionCircuit PRECISION INSTRUMENTATION AMPLIFIER Measurement of very small signals with an amplifier requires close attention to the input impedance of the amplifier, gain of the overall signal on the inputs, and the gain on each input of the amplifier. This is because the difference of the input signal on the two inputs is of the interest and the common signal is considered noise. A classic circuit implementation is an instrumentation amplifier. Instrumentation amplifiers have a finite, accurate, and stable gain. They also have extremely high input impedances and very low output impedances. Finally they have an extremely high CMRR so that the amplifier can only respond to the differential signal. A typical instrumentationamplifierisshowninFigure50. V1 + V01 R2 KR2 - R1 - R1 R11 = a + VOUT - R1 V2 + V02 R2 KR2 Figure50. InstrumentationAmplifier There are two stages in this amplifier. The last stage, output stage, is a differential amplifier. In an ideal case the two amplifiers of the first stage, input stage, would be set up as buffers to isolate the inputs. However they cannot be connected as followers because of mismatch of amplifiers. That is why there is a balancing resistor between the two. The product of the two stages of gain will give the gain of the instrumentation amplifier. Ideally, the CMRR should be infinite. However the output stage has a small non-zero common mode gain which results fromresistormismatch. Copyright©2008–2013,TexasInstrumentsIncorporated SubmitDocumentationFeedback 19 ProductFolderLinks:LMP2231

LMP2231 SNOSB01E–JANUARY2008–REVISEDMARCH2013 www.ti.com In the input stage of the circuit, current is the same across all resistors. This is due to the high input impedance andlowinputbiascurrentoftheLMP2231. GIVEN: I = I R1 R11 (1) ByOhm’sLaw: VO1 - VO2 = (2R1 + R11) IR11 = (2a + 1) R11xIR11 = (2a + 1) V R11 (2) However: V R11 = V1 - V2 (3) Sowehave: V –V =(2a+1)(V –V ) (4) O1 O2 1 2 Nowlookingattheoutputoftheinstrumentationamplifier: KR2 VO = (VO2 - VO1) R2 = -K (VO1 - VO2) (5) SubstitutingfromEquation4: VO = -K (2a + 1) (V1 - V2) (6) Thisshowsthegainoftheinstrumentationamplifiertobe: −K(2a+1) (7) Typicalvaluesforthiscircuitcanbeobtainedbysetting:a=12andK=4.Thisresultsinanoverallgainof−100. SINGLE SUPPLY STRAIN GAGE BRIDGE AMPLIFIER Strain gauges are popular electrical elements used to measure force or pressure. Strain gauges are subjected to an unknown force which is measured as a the deflection on a previously calibrated scale. Pressure is often measured using the same technique; however this pressure needs to be converted into force using an appropriate transducer. Strain gauges are often resistors which are sensitive to pressure or to flexing. Sense resistorvaluesrangefromtensofohmstoseveralhundredkiloohms.Theresistancechangewhichisaresultof applied force across the strain gauge might be 1% of its total value. An accurate and reliable system is needed tomeasurethissmallresistancechange.Bridgeconfigurationsofferareliablemethodforthismeasurement. Bridge sensors are formed of four resistors, connected as a quadrilateral. A voltage source or a current source is used across one of the diagonals to excite the bridge while a voltage detector across the other diagonal measurestheoutputvoltage. Bridges are mainly used as null circuits or to measure a differential voltages. Bridges will have no output voltage if the ratios of two adjacent resistor values are equal. This fact is used in null circuit measurements. These are particularly used in feedback systems which involve electrochemical elements or human interfaces. Null systems forceanactiveresistor,suchasastraingauge,tobalancethebridgebyinfluencingthemeasuredparameter. Often in sensor applications at lease one of the resistors is a variable resistor, or a sensor. The deviation of this activeelementfromitsinitialvalueismeasuredasanindicationofchangeinthemeasuredquantity.Achangein output voltage represents the sensor value change. Since the sensor value change is often very small, the resulting output voltage is very small in magnitude as well. This requires an extensive and very precise amplificationcircuitrysothatsignalfidelitydoesnotchangeafteramplification. Sensitivityofabridgeistheratioofitsmaximumexpectedoutputchangetotheexcitationvoltagechange. 20 SubmitDocumentationFeedback Copyright©2008–2013,TexasInstrumentsIncorporated ProductFolderLinks:LMP2231

LMP2231 www.ti.com SNOSB01E–JANUARY2008–REVISEDMARCH2013 Figure 51 (a) shows a typical bridge sensor and Figure 51(b) shows the bridge with four sensors. R in Figure 51(b) is the nominal value of the sense resistor and the deviations from R are proportional to the quantity beingmeasured. R + ’R R - ’R R1 R2 VOUT EXCITATION VOUT EXCITATION SOURCE SOURCE R3 R4 R - ’R R + ’R (a) (b) R3- R4 VOUT = ’R x VSOURCE R1 R2 R VOUT = x VSOURCE ¤¤§1 +R3¤¤'¤¤§1 +R4¤¤' ' R1§' R2§ Figure51. BridgeSensor Instrumentation amplifiers are great for interfacing with bridge sensors. Bridge sensors often sense a very small differential signal in the presence of a larger common mode voltage. Instrumentation amplifiers reject this commonmodesignal. Figure 52 shows a strain gauge bridge amplifier. In this application the LMP2231 is used to buffer the LM4140's precision output voltage. The LM4140A is a precision voltage reference. The other three LMP2231s are used to form an instrumentation amplifier. This instrumentation amplifier uses the LMP2231's high CMRR and low V OS and TCV to accurately amplify the small differential signal generated by the output of the bridge sensor. This OS amplified signal is then fed into the ADC121S021 which is a 12-bit analog to digital converter. This circuit works onasinglesupplyvoltageof5V. V+ V+ 3 2 - LMP2231 6 LM4140A + 1 PF 1,4,7,8 + V 0.1 PF + V + ½ 10 k: 40 k: 10 PF LMP2232 - 12 k: R+’R R + - V VA LMP2231 IN 1 k: R + ADC121S021 R+’R + V 12 k: - ½ GND LMP2232 10 k: 40 k: + Figure52. StrainGaugeBridgeAmplifier Copyright©2008–2013,TexasInstrumentsIncorporated SubmitDocumentationFeedback 21 ProductFolderLinks:LMP2231

LMP2231 SNOSB01E–JANUARY2008–REVISEDMARCH2013 www.ti.com PORTABLE GAS DETECTION SENSOR Gas sensors are used in many different industrial and medical applications. They generate a current which is proportional to the percentage of a particular gas sensed in an air sample. This current goes through a load resistor and the resulting voltage drop is measured. Depending on the sensed gas and sensitivity of the sensor, the output current can be in the order of tens of microamperes to a few milliamperes. Gas sensor datasheets oftenspecifyarecommendedloadresistorvalueortheysuggestarangeofloadresistorstochoosefrom. Oxygen sensors are used when air quality or oxygen delivered to a patient needs to be monitored. Fresh air contains 20.9% oxygen. Air samples containing less than 18% oxygen are considered dangerous. Oxygen sensors are also used in industrial applications where the environment must lack oxygen. An example is when food is vacuum packed. There are two main categories of oxygen sensors, those which sense oxygen when it is abundantlypresent(i.e.inairornearanoxygentank)andthosewhichdetecttracesofoxygeninppm. Figure 53 shows a typical circuit used to amplify the output of an oxygen detector. The LMP2231 makes an excellent choice for this application as it only draws 10 µA of current and operates on supply voltages down to 1.8V. This application detects oxygen in air. The oxygen sensor outputs a known current through the load resistor. This value changes with the amount of oxygen present in the air sample. Oxygen sensors usually recommend a particular load resistor value or specify a range of acceptable values for the load resistor. Oxygen sensors typically have a life of one to two years. The use of the micropower LMP2231 means minimal power usage by the op amp and it enhances the battery life. Depending on other components present in the circuit design, the battery could last for the entire life of the oxygen sensor. The precision specifications of the LMP2231, such as its very low offset voltage, low TCV , low input bias current, low CMRR, and low PSRR are OS otherfactorswhichmaketheLMP2231agreatchoiceforthisapplication. 99 k: + 1 k: V - 1 k: VOUT + - V RL OXYGEN SENSOR Figure53. PrecisionOxygenSensor 22 SubmitDocumentationFeedback Copyright©2008–2013,TexasInstrumentsIncorporated ProductFolderLinks:LMP2231

LMP2231 www.ti.com SNOSB01E–JANUARY2008–REVISEDMARCH2013 REVISION HISTORY ChangesfromRevisionD(March2013)toRevisionE Page • ChangedlayoutofNationalDataSheettoTIformat.......................................................................................................... 22 Copyright©2008–2013,TexasInstrumentsIncorporated SubmitDocumentationFeedback 23 ProductFolderLinks:LMP2231

PACKAGE OPTION ADDENDUM www.ti.com 6-Feb-2020 PACKAGING INFORMATION Orderable Device Status Package Type Package Pins Package Eco Plan Lead/Ball Finish MSL Peak Temp Op Temp (°C) Device Marking Samples (1) Drawing Qty (2) (6) (3) (4/5) LMP2231AMA/NOPB ACTIVE SOIC D 8 95 Green (RoHS SN Level-1-260C-UNLIM -40 to 125 LMP22 & no Sb/Br) 31AMA LMP2231AMAE/NOPB ACTIVE SOIC D 8 250 Green (RoHS SN Level-1-260C-UNLIM -40 to 125 LMP22 & no Sb/Br) 31AMA LMP2231AMAX/NOPB ACTIVE SOIC D 8 2500 Green (RoHS SN Level-1-260C-UNLIM -40 to 125 LMP22 & no Sb/Br) 31AMA LMP2231AMF/NOPB ACTIVE SOT-23 DBV 5 1000 Green (RoHS SN Level-1-260C-UNLIM -40 to 125 AL5A & no Sb/Br) LMP2231AMFE/NOPB ACTIVE SOT-23 DBV 5 250 Green (RoHS SN Level-1-260C-UNLIM -40 to 125 AL5A & no Sb/Br) LMP2231AMFX/NOPB ACTIVE SOT-23 DBV 5 3000 Green (RoHS SN Level-1-260C-UNLIM -40 to 125 AL5A & no Sb/Br) LMP2231BMA/NOPB ACTIVE SOIC D 8 95 Green (RoHS SN Level-1-260C-UNLIM -40 to 125 LMP22 & no Sb/Br) 31BMA LMP2231BMAE/NOPB ACTIVE SOIC D 8 250 Green (RoHS SN Level-1-260C-UNLIM -40 to 125 LMP22 & no Sb/Br) 31BMA LMP2231BMF/NOPB ACTIVE SOT-23 DBV 5 1000 Green (RoHS SN Level-1-260C-UNLIM -40 to 125 AL5B & no Sb/Br) LMP2231BMFE/NOPB ACTIVE SOT-23 DBV 5 250 Green (RoHS SN Level-1-260C-UNLIM -40 to 125 AL5B & no Sb/Br) LMP2231BMFX/NOPB ACTIVE SOT-23 DBV 5 3000 Green (RoHS SN Level-1-260C-UNLIM -40 to 125 AL5B & no Sb/Br) (1) The marketing status values are defined as follows: ACTIVE: Product device recommended for new designs. LIFEBUY: TI has announced that the device will be discontinued, and a lifetime-buy period is in effect. NRND: Not recommended for new designs. Device is in production to support existing customers, but TI does not recommend using this part in a new design. PREVIEW: Device has been announced but is not in production. Samples may or may not be available. OBSOLETE: TI has discontinued the production of the device. (2) RoHS: TI defines "RoHS" to mean semiconductor products that are compliant with the current EU RoHS requirements for all 10 RoHS substances, including the requirement that RoHS substance do not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered at high temperatures, "RoHS" products are suitable for use in specified lead-free processes. TI may reference these types of products as "Pb-Free". RoHS Exempt: TI defines "RoHS Exempt" to mean products that contain lead but are compliant with EU RoHS pursuant to a specific EU RoHS exemption. Green: TI defines "Green" to mean the content of Chlorine (Cl) and Bromine (Br) based flame retardants meet JS709B low halogen requirements of <=1000ppm threshold. Antimony trioxide based flame retardants must also meet the <=1000ppm threshold requirement. Addendum-Page 1

PACKAGE OPTION ADDENDUM www.ti.com 6-Feb-2020 (3) MSL, Peak Temp. - The Moisture Sensitivity Level rating according to the JEDEC industry standard classifications, and peak solder temperature. (4) There may be additional marking, which relates to the logo, the lot trace code information, or the environmental category on the device. (5) Multiple Device Markings will be inside parentheses. Only one Device Marking contained in parentheses and separated by a "~" will appear on a device. If a line is indented then it is a continuation of the previous line and the two combined represent the entire Device Marking for that device. (6) Lead/Ball Finish - Orderable Devices may have multiple material finish options. Finish options are separated by a vertical ruled line. Lead/Ball Finish values may wrap to two lines if the finish value exceeds the maximum column width. Important Information and Disclaimer:The information provided on this page represents TI's knowledge and belief as of the date that it is provided. TI bases its knowledge and belief on information provided by third parties, and makes no representation or warranty as to the accuracy of such information. Efforts are underway to better integrate information from third parties. TI has taken and continues to take reasonable steps to provide representative and accurate information but may not have conducted destructive testing or chemical analysis on incoming materials and chemicals. TI and TI suppliers consider certain information to be proprietary, and thus CAS numbers and other limited information may not be available for release. In no event shall TI's liability arising out of such information exceed the total purchase price of the TI part(s) at issue in this document sold by TI to Customer on an annual basis. Addendum-Page 2

PACKAGE MATERIALS INFORMATION www.ti.com 24-Aug-2017 TAPE AND REEL INFORMATION *Alldimensionsarenominal Device Package Package Pins SPQ Reel Reel A0 B0 K0 P1 W Pin1 Type Drawing Diameter Width (mm) (mm) (mm) (mm) (mm) Quadrant (mm) W1(mm) LMP2231AMAE/NOPB SOIC D 8 250 178.0 12.4 6.5 5.4 2.0 8.0 12.0 Q1 LMP2231AMAX/NOPB SOIC D 8 2500 330.0 12.4 6.5 5.4 2.0 8.0 12.0 Q1 LMP2231AMF/NOPB SOT-23 DBV 5 1000 178.0 8.4 3.2 3.2 1.4 4.0 8.0 Q3 LMP2231AMFE/NOPB SOT-23 DBV 5 250 178.0 8.4 3.2 3.2 1.4 4.0 8.0 Q3 LMP2231AMFX/NOPB SOT-23 DBV 5 3000 178.0 8.4 3.2 3.2 1.4 4.0 8.0 Q3 LMP2231BMAE/NOPB SOIC D 8 250 178.0 12.4 6.5 5.4 2.0 8.0 12.0 Q1 LMP2231BMF/NOPB SOT-23 DBV 5 1000 178.0 8.4 3.2 3.2 1.4 4.0 8.0 Q3 LMP2231BMFE/NOPB SOT-23 DBV 5 250 178.0 8.4 3.2 3.2 1.4 4.0 8.0 Q3 LMP2231BMFX/NOPB SOT-23 DBV 5 3000 178.0 8.4 3.2 3.2 1.4 4.0 8.0 Q3 PackMaterials-Page1

PACKAGE MATERIALS INFORMATION www.ti.com 24-Aug-2017 *Alldimensionsarenominal Device PackageType PackageDrawing Pins SPQ Length(mm) Width(mm) Height(mm) LMP2231AMAE/NOPB SOIC D 8 250 210.0 185.0 35.0 LMP2231AMAX/NOPB SOIC D 8 2500 367.0 367.0 35.0 LMP2231AMF/NOPB SOT-23 DBV 5 1000 210.0 185.0 35.0 LMP2231AMFE/NOPB SOT-23 DBV 5 250 210.0 185.0 35.0 LMP2231AMFX/NOPB SOT-23 DBV 5 3000 210.0 185.0 35.0 LMP2231BMAE/NOPB SOIC D 8 250 210.0 185.0 35.0 LMP2231BMF/NOPB SOT-23 DBV 5 1000 210.0 185.0 35.0 LMP2231BMFE/NOPB SOT-23 DBV 5 250 210.0 185.0 35.0 LMP2231BMFX/NOPB SOT-23 DBV 5 3000 210.0 185.0 35.0 PackMaterials-Page2

PACKAGE OUTLINE DBV0005A SOT-23 - 1.45 mm max height SCALE 4.000 SMALL OUTLINE TRANSISTOR C 3.0 2.6 0.1 C 1.75 1.45 1.45 B A 0.90 PIN 1 INDEX AREA 1 5 2X 0.95 3.05 2.75 1.9 1.9 2 4 3 0.5 5X 0.3 0.15 0.2 C A B (1.1) TYP 0.00 0.25 GAGE PLANE 0.22 TYP 0.08 8 TYP 0.6 0 0.3 TYP SEATING PLANE 4214839/E 09/2019 NOTES: 1. All linear dimensions are in millimeters. Any dimensions in parenthesis are for reference only. Dimensioning and tolerancing per ASME Y14.5M. 2. This drawing is subject to change without notice. 3. Refernce JEDEC MO-178. 4. Body dimensions do not include mold flash, protrusions, or gate burrs. Mold flash, protrusions, or gate burrs shall not exceed 0.15 mm per side. www.ti.com

EXAMPLE BOARD LAYOUT DBV0005A SOT-23 - 1.45 mm max height SMALL OUTLINE TRANSISTOR PKG 5X (1.1) 1 5 5X (0.6) SYMM (1.9) 2 2X (0.95) 3 4 (R0.05) TYP (2.6) LAND PATTERN EXAMPLE EXPOSED METAL SHOWN SCALE:15X SOLDER MASK SOLDER MASK METAL UNDER METAL OPENING OPENING SOLDER MASK EXPOSED METAL EXPOSED METAL 0.07 MAX 0.07 MIN ARROUND ARROUND NON SOLDER MASK SOLDER MASK DEFINED DEFINED (PREFERRED) SOLDER MASK DETAILS 4214839/E 09/2019 NOTES: (continued) 5. Publication IPC-7351 may have alternate designs. 6. Solder mask tolerances between and around signal pads can vary based on board fabrication site. www.ti.com

EXAMPLE STENCIL DESIGN DBV0005A SOT-23 - 1.45 mm max height SMALL OUTLINE TRANSISTOR PKG 5X (1.1) 1 5 5X (0.6) SYMM 2 (1.9) 2X(0.95) 3 4 (R0.05) TYP (2.6) SOLDER PASTE EXAMPLE BASED ON 0.125 mm THICK STENCIL SCALE:15X 4214839/E 09/2019 NOTES: (continued) 7. Laser cutting apertures with trapezoidal walls and rounded corners may offer better paste release. IPC-7525 may have alternate design recommendations. 8. Board assembly site may have different recommendations for stencil design. www.ti.com

PACKAGE OUTLINE D0008A SOIC - 1.75 mm max height SCALE 2.800 SMALL OUTLINE INTEGRATED CIRCUIT C SEATING PLANE .228-.244 TYP [5.80-6.19] .004 [0.1] C A PIN 1 ID AREA 6X .050 [1.27] 8 1 2X .189-.197 [4.81-5.00] .150 NOTE 3 [3.81] 4X (0 -15 ) 4 5 8X .012-.020 B .150-.157 [0.31-0.51] .069 MAX [3.81-3.98] .010 [0.25] C A B [1.75] NOTE 4 .005-.010 TYP [0.13-0.25] 4X (0 -15 ) SEE DETAIL A .010 [0.25] .004-.010 0 - 8 [0.11-0.25] .016-.050 [0.41-1.27] DETAIL A (.041) TYPICAL [1.04] 4214825/C 02/2019 NOTES: 1. Linear dimensions are in inches [millimeters]. Dimensions in parenthesis are for reference only. Controlling dimensions are in inches. Dimensioning and tolerancing per ASME Y14.5M. 2. This drawing is subject to change without notice. 3. This dimension does not include mold flash, protrusions, or gate burrs. Mold flash, protrusions, or gate burrs shall not exceed .006 [0.15] per side. 4. This dimension does not include interlead flash. 5. Reference JEDEC registration MS-012, variation AA. www.ti.com

EXAMPLE BOARD LAYOUT D0008A SOIC - 1.75 mm max height SMALL OUTLINE INTEGRATED CIRCUIT 8X (.061 ) [1.55] SYMM SEE DETAILS 1 8 8X (.024) [0.6] SYMM (R.002 ) TYP [0.05] 5 4 6X (.050 ) [1.27] (.213) [5.4] LAND PATTERN EXAMPLE EXPOSED METAL SHOWN SCALE:8X SOLDER MASK SOLDER MASK METAL OPENING OPENING METAL UNDER SOLDER MASK EXPOSED METAL EXPOSED METAL .0028 MAX .0028 MIN [0.07] [0.07] ALL AROUND ALL AROUND NON SOLDER MASK SOLDER MASK DEFINED DEFINED SOLDER MASK DETAILS 4214825/C 02/2019 NOTES: (continued) 6. Publication IPC-7351 may have alternate designs. 7. Solder mask tolerances between and around signal pads can vary based on board fabrication site. www.ti.com

EXAMPLE STENCIL DESIGN D0008A SOIC - 1.75 mm max height SMALL OUTLINE INTEGRATED CIRCUIT 8X (.061 ) [1.55] SYMM 1 8 8X (.024) [0.6] SYMM (R.002 ) TYP [0.05] 5 4 6X (.050 ) [1.27] (.213) [5.4] SOLDER PASTE EXAMPLE BASED ON .005 INCH [0.125 MM] THICK STENCIL SCALE:8X 4214825/C 02/2019 NOTES: (continued) 8. Laser cutting apertures with trapezoidal walls and rounded corners may offer better paste release. IPC-7525 may have alternate design recommendations. 9. Board assembly site may have different recommendations for stencil design. www.ti.com

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