INA128U/2K5

INA128, INA129 SBOS051F – OCTOBER 1995 – REVISED MAY 2022 INA12x Precision, Low-Power Instrumentation Amplifiers 1 Features 3 Description • • • • • • • • • • The INA128 and INA129 (INA12x) are low-power, general-purpose instrumentation amplifiers that offer excellent accuracy. The versatile three op amp design and small size make these amplifiers an excellent choice for a wide range of applications. Currentfeedback input circuitry provides wide bandwidth even at high gain (200 kHz at G = 100). Low offset voltage: 50 μV, maximum Low drift: 0.5 μV/°C, maximum Low input bias current: 5 nA, maximum Low noise: 8 nV/√Hz, 0.2 μVpp High CMR: 120 dB, minimum Bandwidth: 1.3 MHz (G = 1) Inputs protected to ±40 V Wide supply range: ±2.25 V to ±18 V Low quiescent current: 700 μA Packages: 8-pin plastic DIP, SO-8 A single external resistor sets any gain from 1 to 10,000. The INA128 provides an industry-standard gain equation with a 50-kΩ resistor. The INA129 gain equation uses a 49.4-kΩ resistor to allow for drop-in replacements of comparable devices. 2 Applications • • • • • • Pressure transmitter Temperature transmitter Weigh scale Electrocardiogram (ECG) Analog input module Data acquisition (DAQ) The INA12x are available in plastic DIP and surfacemount packages, specified for the –40°C to +85°C temperature range. The INA128 is also available in a dual configuration, the INA2128. The upgraded INA828 offers a lower input bias current (0.6 nA, max) and lower noise (7 nV/√Hz) at the same quiescent current. See the Device Comparison Table for a selection of precision instrumentation amplifiers from Texas Instruments. Device Information PART NUMBER INA128, INA129 (1) PACKAGE(1) BODY SIZE (NOM) SOIC (8) 3.91 mm × 4.90 mm PDIP (8) 6.35 mm × 9.81 mm For all available packages, see the package option addendum at the end of the data sheet. V+ INA128: 7 G=1+ INA128, INA129 VIN– 2 Overvoltage Protection INA129: A1 1 25 k (1) 40 k A3 RG VIN+ G=1+ 6 49.4 k RG VO (1) 8 3 40 k 50 k RG 25 k A2 Overvoltage Protection
(1) INA129: 24.7 k 5 40 k 40 k Ref 4 V Simplified Schematic An IMPORTANT NOTICE at the end of this data sheet addresses availability, warranty, changes, use in safety-critical applications, intellectual property matters and other important disclaimers. PRODUCTION DATA. INA128, INA129 www.ti.com SBOS051F – OCTOBER 1995 – REVISED MAY 2022 Table of Contents 1 Features............................................................................1 2 Applications..................................................................... 1 3 Description.......................................................................1 4 Revision History.............................................................. 2 5 Device Comparison Table...............................................4 6 Pin Configuration and Functions...................................4 7 Specifications.................................................................. 5 7.1 Absolute Maximum Ratings........................................ 5 7.2 ESD Ratings .............................................................. 5 7.3 Recommended Operating Conditions.........................5 7.4 Thermal Information....................................................5 7.5 Electrical Characteristics.............................................6 7.6 Typical Characteristics................................................ 8 8 Detailed Description......................................................12 8.1 Overview................................................................... 12 8.2 Functional Block Diagram......................................... 12 8.3 Feature Description...................................................13 8.4 Device Functional Modes..........................................13 9 Application and Implementation.................................. 14 9.1 Application Information............................................. 14 9.2 Typical Application.................................................... 15 9.3 System Examples..................................................... 19 10 Power Supply Recommendations..............................21 10.1 Low-Voltage Operation........................................... 21 11 Layout........................................................................... 21 11.1 Layout Guidelines................................................... 21 11.2 Layout Example...................................................... 21 12 Device and Documentation Support..........................22 12.1 Device Support....................................................... 22 12.2 Documentation Support.......................................... 22 12.3 Receiving Notification of Documentation Updates..22 12.4 Support Resources................................................. 22 12.5 Trademarks............................................................. 22 12.6 Electrostatic Discharge Caution..............................23 12.7 Glossary..................................................................23 13 Mechanical, Packaging, and Orderable Information.................................................................... 23 4 Revision History NOTE: Page numbers for previous revisions may differ from page numbers in the current version. Changes from Revision E (April 2019) to Revision F (May 2022) Page • Updated the numbering format for tables, figures, and cross-references throughout the document..................1 • Added bandwidth and noise specifications in Features .....................................................................................1 • Changed Applications to link to latest end-equipment solutions on ti.com......................................................... 1 • Changed reference from INA819 to INA818 in Device Comparison Table ........................................................ 4 • Added single supply specification to Absolute Maximum Ratings ..................................................................... 5 • Added note clarifying output short-circuit "to ground" in Absolute Maximum Ratings refers to short-circuit to VS / 2...................................................................................................................................................................5 • Added single supply specification to Recommended Operating Conditions ......................................................5 • Changed input common-mode voltage range specification from V – 2 to (V–) + 2 in Recommended Operating Conditions ..........................................................................................................................................................5 • Deleted INA128-HT and INA129-HT operating temperature specifications from Recommended Operating Conditions ..........................................................................................................................................................5 • Added specified temperature range to Recommended Operating Conditions .................................................. 5 • Added VREF = 0 V, VCM = VS / 2, and G = 1 to "unless otherwise noted" conditions in Electrical Characteristics and Typical Characteristics for clarity.........................................................................................6 • Changed test condition for offset voltage drift specification in Electrical Characteristics from "TA = TMIN to TMAX" to "TA = –40°C to +85°C" for clarity...................................................................................................... 6 • Changed typical long-term stability specification from ±0.1±3/G µV/mo to ±0.2±3/G µV/mo in Electrical Characteristics ................................................................................................................................................... 6 • Changed common-mode voltage specification from (V–) + 2 V minimum and (V+) – 2 V minimum across two rows to (V– ) + 2 V minimum and (V+) – 2 V maximum across one row in Electrical Characteristics ...............6 • Deleted typical common-mode voltage specifications in Electrical Characteristics ..........................................6 • Added test condition of "RS = 0 Ω" to safe input voltage specification in Electrical Characteristics for clarity....6 • Added test condition of "TA = –40°C to +85°C" to input bias current drift specification in Electrical Characteristics for clarity.................................................................................................................................... 6 • Added test condition of "TA = –40°C to +85°C" to input offset current drift specification in Electrical Characteristics for clarity.................................................................................................................................... 6 • Changed maximum gain error specification for INA128PA/UA and INA129PA/UA with G = 1 from ±0.01% to ±0.1% in Electrical Characteristics ................................................................................................................ 6 2 Submit Document Feedback Copyright © 2022 Texas Instruments Incorporated Product Folder Links: INA128 INA129 INA128, INA129 www.ti.com • • • • • • • • • • • • • • • SBOS051F – OCTOBER 1995 – REVISED MAY 2022 Added test condition of "TA = –40°C to +85°C" for gain drift in Electrical Characteristics for clarity...................6 Changed parameter names from "Voltage - Positive" to "Positive output voltage swing" and from "Voltage Negative" to "Negative output voltage swing" in Electrical Characteristics ........................................................6 Deleted typical positive and negative output voltage swing specifications in Electrical Characteristics ............6 Added test condition of "Continuous to VS / 2" to short-circuit current specification in Electrical Characteristics for clarity............................................................................................................................................................. 6 Changed typical bandwidth specification for G = 10 from 700 kHz to 640 kHz in Electrical Characteristics ..... 6 Changed typical slew rate specification from 4 V/µs to 1.2 V/µs in Electrical Characteristics ........................... 6 Changed typical settling time specification for G = 1, G = 10, and G = 100 from 7 µs, 7 µs, and 9 µs respectively to 12 µs, 12 µs, and 12 µs, in Electrical Characteristics ........................................................ 6 Deleted redundant voltage range, operating temperature range, and specification temperature range specifications from Electrical Characteristics .....................................................................................................6 Changed Figures 7-1, 7-3, 7-4, 7-9, 7-10, 7-11, 7-16, 7-17, 7-20, 7-21............................................................. 8 Changed values discussed in Input Common-Mode Range from typical input common-mode voltage range values to maximum and minimum values.........................................................................................................14 Changed Figure 9-1 to fix missing text and include reference voltage............................................................. 15 Added more detailed guidance concerning REF pin in Design Requirements ................................................ 15 Changed Figures 9-6, 9-7.................................................................................................................................18 Changed Figures 9-10 and 9-11 to fix missing text...........................................................................................19 Added Related Documentation links to Device and Documentation Support ..................................................22 Changes from Revision D (January 2018) to Revision E (April 2019) Page • Added information about the newer, upgraded INA828......................................................................................1 • Added Device Comparison Table ...................................................................................................................... 4 Changes from Revision C (October 2015) to Revision D (January 2018) Page • Added top navigator icon for TI Reference Design ............................................................................................1 • Changed "±0.5±0/G" to "±0.5±20/G" in MAX column of Offset voltage RTI vs temperature row of Electrical Characteristics.................................................................................................................................................... 6 Changes from Revision B (February 2005) to Revision C (April 2015) Page • Added ESD Ratings table, Feature Description section, Device Functional Modes, Application and Implementation section, Power Supply Recommendations section, Layout section, Device and Documentation Support section, and Mechanical, Packaging, and Orderable Information section................... 1 Submit Document Feedback Copyright © 2022 Texas Instruments Incorporated Product Folder Links: INA128 INA129 3 INA128, INA129 www.ti.com SBOS051F – OCTOBER 1995 – REVISED MAY 2022 5 Device Comparison Table DEVICE DESCRIPTION GAIN EQUATION RG PINS AT PIN G = 1 + 50 kΩ / RG 1, 8 G = 1 + 49.4 kΩ / RG 2, 3 INA818 35-µV offset, 0.4-µV/°C VOS drift, 8-nV/√Hz noise, low-power, precision instrumentation amplifier INA821 35-µV offset, 0.4-µV/°C VOS drift, 7-nV/√Hz noise, high-bandwidth, precision instrumentation amplifier INA828 50-µV offset, 0.5-µV/°C VOS drift, 7-nV/√Hz noise, low-power, precision instrumentation amplifier G = 1 + 50 kΩ / RG 1, 8 INA333 25-µV VOS, 0.1-µV/°C VOS drift, 1.8-V to 5-V, RRO, 50-µA IQ, chopper-stabilized INA G = 1 + 100 kΩ / RG 1, 8 PGA280 20-mV to ±10-V programmable gain IA with 3-V or 5-V differential output; analog supply up to ±18 V Digital programmable N/A INA159 G = 0.2 V differential amplifier for ±10-V to 3-V and 5-V conversion G = 0.2 V/V N/A PGA112 Precision programmable gain op amp with SPI Digital programmable N/A 6 Pin Configuration and Functions RG 1 8 RG V− IN 2 7 V+ V+IN 3 6 VO V− 4 5 Ref Figure 6-1. D (8-Pin SOIC) and P (8-Pin PDIP) Packages, Top View Table 6-1. Pin Functions PIN NAME REF 4 NO. TYPE DESCRIPTION 5 Input RG 1,8 — Reference input. This pin must be driven by low impedance or connected to ground. V– 4 Power Negative supply V+ 7 Power Positive supply VIN– 2 Input Negative input VIN+ 3 Input Positive input VO 6 Output Gain setting pin. For gains greater than 1, place a gain resistor between pin 1 and pin 8. Output Submit Document Feedback Copyright © 2022 Texas Instruments Incorporated Product Folder Links: INA128 INA129 INA128, INA129 www.ti.com SBOS051F – OCTOBER 1995 – REVISED MAY 2022 7 Specifications 7.1 Absolute Maximum Ratings over operating free-air temperature range (unless otherwise noted)(1) MIN VS Supply voltage MAX Dual supply, VS = (V+) – (V–) ±18 Single supply, VS = (V+) – 0 V 36 Analog input voltage Output short-circuit(2) TA –40 Junction temperature Lead temperature (soldering, 10 s) (1) (2) V ±40 V 125 °C 150 °C 300 °C 125 °C Continuous Operating temperature Tstg UNIT Storage temperature –55 Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. These are stress ratings only, which do not imply functional operation of the device at these or any other conditions beyond those indicated under Recommended Operating Conditions. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability. Short-circuit to VS / 2. 7.2 ESD Ratings VALUE V(ESD) (1) (2) Electrostatic discharge Human-body model (HBM), per ANSI/ESDA/JEDEC JS-001(1) ±2000 Charged-device model (CDM), per JEDEC specification JESD22-C101(2) ±50 UNIT V JEDEC document JEP155 states that 500-V HBM allows safe manufacturing with a standard ESD control process. JEDEC document JEP157 states that 250-V CDM allows safe manufacturing with a standard ESD control process. 7.3 Recommended Operating Conditions over operating free-air temperature range (unless otherwise noted) VS Single-supply Supply voltage Dual-supply Input common-mode voltage range for VO = 0 V TA MIN TYP MAX 4.5 30 36 ±2.25 ±15 ±18 UNIT V (V–) + 2 (V+) – 2 V –40 85 °C Specified temperature 7.4 Thermal Information INA12x THERMAL METRIC(1) D (SOIC) P (PDIP) 8 PINS 8 PINS UNIT RθJA Junction-to-ambient thermal resistance 110 46.1 °C/W RθJC(top) Junction-to-case (top) thermal resistance 57 34.1 °C/W RθJB Junction-to-board thermal resistance 54 23.4 °C/W ψJT Junction-to-top characterization parameter 11 11.3 °C/W ψJB Junction-to-board characterization parameter 53 23.2 °C/W (1) For more information about traditional and new thermal metrics, see the Semiconductor and IC Package Thermal Metrics application report. Submit Document Feedback Copyright © 2022 Texas Instruments Incorporated Product Folder Links: INA128 INA129 5 INA128, INA129 www.ti.com SBOS051F – OCTOBER 1995 – REVISED MAY 2022 7.5 Electrical Characteristics at TA = 25°C, VS = ±15 V, RL = 10 kΩ, VREF = 0 V, VCM = VS / 2, and G = 1 (unless otherwise noted) PARAMETER TEST CONDITIONS MIN TYP MAX INA12xP, INA12xU ±10 ±100 / G ±50 ±500 / G INA12xPA, INA12xUA ±25 ±100 / G ±125 ±1000 / G UNIT INPUT VOS PSRR Offset voltage (RTI) 1 ≤ G ≤ 10000 Offset voltage drift (RTI) TA = –40°C to +85°C Power-supply rejection ratio (RTI) VS = ±2.25 V to ±18 V INA12xP, INA12xU ±0.2 ±2 / G ±0.5 ±20 / G INA12xPA, INA12xUA ±0.2 ±5 / G ±1 ±20 / G ±0.2 ±20 / G ±1 ±100 / G INA12xP, INA12xU INA12xPA, INA12xUA ±2 ±200 / G Long-term stability Input impedance VCM ±0.2 ±3 / G Differential Common-mode voltage(2) VO = 0 V Safe input voltage RS = 0 Ω G=1 G = 10 CMRR Common-mode rejection ΔRS = 1 kΩ, VCM = ±13 V ratio G = 100 G = 1000 INA12xP, INA12xU 80 INA12xPA, INA12xUA 73 INA12xP, INA12xU INA12xPA, INA12xUA INA12xP, INA12xU 100 (V+) – 2 V ±40 V 86 106 93 120 INA12xPA, INA12xUA 110 INA12xP, INA12xU 120 INA12xPA, INA12xUA 110 µV/V GΩ || pF 100 || 9 (V–) + 2 µV/°C µV/mo 10 || 2 Common-mode µV dB 125 130 INPUT BIAS CURRENT IB Input bias current Input bias current drift IOS Input offset current Input offset current drift INA12xP, INA12xU ±2 INA12xPA, INA12xUA ±5 ±10 TA = –40°C to +85°C ±30 INA12xP, INA12xU ±1 INA12xPA, INA12xUA pA/℃ ±5 ±10 TA = –40°C to +85°C ±30 nA nA nA pA/℃ NOISE eN Voltage noise (RTI) G = 1000, RS = 0 Ω f = 10 Hz 10 f = 100 Hz 8 f = 1 kHz fB = 0.1 Hz to 10 Hz In 6 Current noise 8 0.2 f = 10 Hz 0.9 f = 1 kHz 0.3 fB = 0.1 Hz to 10 Hz 30 Submit Document Feedback nV/√Hz µVPP pA/√Hz pAPP Copyright © 2022 Texas Instruments Incorporated Product Folder Links: INA128 INA129 INA128, INA129 www.ti.com SBOS051F – OCTOBER 1995 – REVISED MAY 2022 7.5 Electrical Characteristics (continued) at TA = 25°C, VS = ±15 V, RL = 10 kΩ, VREF = 0 V, VCM = VS / 2, and G = 1 (unless otherwise noted) PARAMETER TEST CONDITIONS MIN TYP MAX UNIT GAIN Gain equation G INA128 1 + (50 kΩ / RG) INA129 1 + (49.4 kΩ / RG) Gain 1 G=1 G = 10 GE Gain error G = 100 G = 1000 Gain drift(4) TA = –40°C to +85°C G = 1, VO = ±13.6 V Gain nonlinearity(1) G = 10 G = 100 INA12xP, INA12xU V/V 10000 ±0.01 INA12xPA, INA12xUA V/V ±0.024 ±0.1 INA12xP, INA12xU ±0.02 INA12xPA, INA12xUA ±0.4 ±0.5 INA12xP, INA12xU ±0.05 INA12xPA, INA12xUA ±0.5 % ±0.7 INA12xP, INA12xU ±0.5 ±1 ±1 ±10 ±25 ±100 ±0.0001 ±0.001 INA12xPA, INA12xUA ±2 50-kΩ or 49.4-kΩ resistance(3) INA12xP, INA12xU INA12xPA, INA12xUA ppm/°C ±0.002 INA12xP, INA12xU ±0.0003 INA12xPA, INA12xUA ±0.002 ±0.004 % of FSR INA12xP, INA12xU ±0.0005 INA12xPA, INA12xUA ±0.002 ±0.004 G = 1000 ±0.001 OUTPUT Positive output voltage swing (V+) – 1.4 V Negative output voltage swing (V–) + 1.4 V CL Load capacitance Stable operation ISC Short-circuit current Continuous to VS / 2 1000 pF +6/–15 mA G=1 1.3 MHz G = 10 640 G = 100 200 FREQUENCY RESPONSE BW Bandwidth, –3 dB SR Slew rate tS G = 1000 20 G = 5, VO = ±10 V 1.2 Settling time To 0.01% Overload recovery 50% input overload G=1 12 G = 10 12 G = 100 12 G = 1000 80 kHz V/µs µs 4 µs POWER SUPPLY IQ (1) (2) (3) (4) Quiescent current VIN = 0 V ±700 ±750 µA Nonlinearity measurements in G = 1000 are dominated by noise. Typical nonlinearity is ±0.001% Input common-mode voltage varies with output voltage; see Typical Characteristics. Temperature coefficient of the 50-kΩ or 49.4-kΩ term in the gain equation. Specified by wafer test. Submit Document Feedback Copyright © 2022 Texas Instruments Incorporated Product Folder Links: INA128 INA129 7 INA128, INA129 www.ti.com SBOS051F – OCTOBER 1995 – REVISED MAY 2022 7.6 Typical Characteristics at TA = 25°C, VS = ±15 V, RL = 10 kΩ, VREF = 0 V, VCM = VS / 2, and G = 1 (unless otherwise noted) 80 140 60 Common−Mode Rejection (dB) G=1 G = 10 G = 100 G = 1000 Gain (dB) 40 20 0 -20 G = 1000V/V G = 100V/V 120 G = 10V/V 100 G = 1V/V 80 60 40 20 0 -40 100 1k 10k 100k 1M 10M Frequency (Hz) 10 100 1k 100k 10k 1M Frequency (Hz) C001 Figure 7-1. Gain vs Frequency Figure 7-2. Common-Mode Rejection vs Frequency 160 140 Negative Power Supply Rejection Ratio (dB) Positive Power Supply Rejection Ratio (dB) 140 120 100 80 60 40 G=1 G = 10 G = 100 G = 1000 20 0 10 100 80 60 G=1 G = 10 G = 100 G = 1000 40 20 0 100 1k Frequency (Hz) 10k 1 100k 10 10k 100k C004 5 G ≥ 10 G ≥ 10 Common−Mode Voltage (V) G=1 G=1 5 VD/2 0 VD/2 + −5 +15V − + VO − Ref + VCM − 15V −10 3 2 G ≥ 10 G ≥ 10 4 10 G=1 G=1 G ≥ 10 1 0 G=1 −1 −2 −3 VS = ±5V VS = ±2.5V −4 −5 −10 −5 0 5 10 15 −5 −4 Output Voltage (V) −3 −2 −1 0 1 2 3 4 5 Output Voltage (V) VS = ±15 V VS = ±5 V, ±2.5 V Figure 7-5. Input Common-Mode Range vs Output Voltage 8 1k Figure 7-4. Negative Power Supply Rejection vs Frequency 15 −15 −15 100 Frequency (Hz) Figure 7-3. Positive Power Supply Rejection vs Frequency Common−Mode Voltage (V) 120 Figure 7-6. Input Common-Mode Range vs Output Voltage Submit Document Feedback Copyright © 2022 Texas Instruments Incorporated Product Folder Links: INA128 INA129 INA128, INA129 www.ti.com SBOS051F – OCTOBER 1995 – REVISED MAY 2022 7.6 Typical Characteristics (continued) 100 1k 100 Input Bias Current Noise (pA/ Hz) 0.01%
G = 1 V/V 10 100 G = 10 V/V 1 10 G = 100 V/V, 1000 V/V Current Noise Settling Time (ms) 0.1% 10 1 0.1 1 1 10 100 1k 1 10k 10 100 Figure 7-8. Settling Time vs Gain Figure 7-7. Input-Referred Noise vs Frequency 0.85 0.825 10 20 8 15 6 Input Current (mA) Quiescent Current (mA) 0.8 0.775 0.75 0.725 0.7 0.675 0.65 0.625 10 4 2 5 0 0 ±2 -5 ±4 -10 ±6 0.6 Unit 1 Unit 2 0.575 0.55 -40 1000 Gain (V/V) Frequency (Hz) -20 0 20 40 60 80 Temperature ( C) 100 120 Input Current ±8 -15 Output Voltage -20 ±10 ±40 140 ±30 ±20 ±10 0 10 20 30 40 Input Voltage (V) Figure 7-9. Quiescent Current vs Temperature Output Voltage (V) Input-Referred Voltage Noise (nV/ Hz) at TA = 25°C, VS = ±15 V, RL = 10 kΩ, VREF = 0 V, VCM = VS / 2, and G = 1 (unless otherwise noted) C015 Figure 7-10. Input Overvoltage V/I Characteristics Input Bias Current (nA) 2 1 IOS 0 IB −1 Typical IB and IOS Range ±2nA at 25°C −2 −75 −50 −25 0 25 50 75 100 125 Temperature (°C) Figure 7-11. Input Offset Voltage Warm-Up Figure 7-12. Input Bias Current vs Temperature Submit Document Feedback Copyright © 2022 Texas Instruments Incorporated Product Folder Links: INA128 INA129 9 INA128, INA129 www.ti.com SBOS051F – OCTOBER 1995 – REVISED MAY 2022 7.6 Typical Characteristics (continued) (V+) (V+) (V+)−0.4 (V+)−0.4 (V+)−0.8 (V+)−1.2 (V−)+1.2 (V−)+0.8 (V−)+0.4 (V+)−0.8 (V+)−1.2 (V−)+1.2 (V−)+0.8 (V−)+0.4 Output Voltage Swing (V) (V+) (V+)−0.4 Output Voltage Swing (V) Output Voltage (V) at TA = 25°C, VS = ±15 V, RL = 10 kΩ, VREF = 0 V, VCM = VS / 2, and G = 1 (unless otherwise noted) +25°C (V+)−0.8 (V+)−1.2 +85°C −40°C RL = 10kΩ +25°C (V−)+1.2 −40°C +85°C (V−)+0.8 +85°C −40°C (V−)+0.4 (V−) (V−) 0 1 2 3 4 (V−) 0 Output Current (mA) 5 10 15 20 Power Supply Voltage (V) Figure 7-14. Output Voltage Swing vs Power Supply Voltage Figure 7-13. Output Voltage Swing vs Output Current 18 20 VS = ±15 V 18 −ISC VS = ±5 V 16 14 Output Amplitude (Vp) Short−Circuit Current (mA) 16 12 10 8 6 +ISC 4 2 14 12 10 8 6 4 2 0 0 −75 −50 −25 0 25 50 75 100 125 100 1 -40 0.1 -60 -80 0.01 G=1 G = 10 G = 100 10 100 1k Frequency (Hz) 10k -100 100k Total Harmonic Distortion + Noise (dB) Total Harmonic Distortion + Noise (%) Figure 7-15. Short Circuit Output Current vs Temperature 0.001 1k 10k 100k 1M 10M Frequency (Hz) Temperature (°C) C001 Figure 7-16. Maximum Output Voltage vs Frequency 0.1µV/div 1s/div C002 G ≥ 100 Figure 7-17. Total Harmonic Distortion + Noise vs Frequency 10 Figure 7-18. 0.1 to 10-Hz Input-Referred Voltage Noise Submit Document Feedback Copyright © 2022 Texas Instruments Incorporated Product Folder Links: INA128 INA129 INA128, INA129 www.ti.com SBOS051F – OCTOBER 1995 – REVISED MAY 2022 7.6 Typical Characteristics (continued) at TA = 25°C, VS = ±15 V, RL = 10 kΩ, VREF = 0 V, VCM = VS / 2, and G = 1 (unless otherwise noted) G=1 G = 100 20mV/div 20mV/div G = 10 G = 1000 20µs/div 5µs/div G = 100, 1000 G = 1, 10 Figure 7-20. Small Signal Amplitude (2 V/div) Input, G = 1 Output, G = 1 Input, G = 10 Output, G = 10 Amplitude (2 V/div) Figure 7-19. Small Signal Input Step (Not to Scale) Output, G = 100 Output, G = 1000 Time (10 s/div) Time (10 s/div) G = 1, 10 G = 100, 1000 Figure 7-21. Large Signal Figure 7-22. Large Signal Submit Document Feedback Copyright © 2022 Texas Instruments Incorporated Product Folder Links: INA128 INA129 11 INA128, INA129 www.ti.com SBOS051F – OCTOBER 1995 – REVISED MAY 2022 8 Detailed Description 8.1 Overview The INA128 and INA129 (INA12x) instrumentation amplifiers are outfitted with an input protection circuit and input buffer amplifiers. These features eliminate the need for input impedance matching and make the amplifier an excellent choice for use in measurement and test equipment. Additional characteristics of the INA12x include a very-low dc offset, low drift, low noise, very-high open-loop gain, very-high common-mode rejection ratio, and very-high input impedances. The INA12x is used where great accuracy and stability of the circuit, both short and long term, are required. 8.2 Functional Block Diagram REF Overvoltage Protection + RG (Optional) +IN + –IN 12 Overvoltage Protection OUT + Submit Document Feedback Copyright © 2022 Texas Instruments Incorporated Product Folder Links: INA128 INA129 INA128, INA129 www.ti.com SBOS051F – OCTOBER 1995 – REVISED MAY 2022 8.3 Feature Description The INA12x are low power, general-purpose instrumentation amplifiers offering excellent accuracy. The versatile three-op-amp design and small size make the amplifiers an excellent choice for a wide range of applications. Current-feedback input circuitry provides wide bandwidth, even at high gain. A single external resistor sets any gain from 1 to 10,000. The INA12x are laser trimmed for very low offset voltage (25 μV typical) and high common-mode rejection (93 dB at G ≥ 100). These devices operate with power supplies as low as ±2.25 V, and a quiescent current of 2 mA, typically. The internal input protection can withstand up to ±40 V without damage, as shown in Figure 7-10. 8.3.1 Noise Performance The INA12x provide very low noise in most applications. Low-frequency noise is approximately 0.2 µVPP measured from 0.1 to 10 Hz (G ≥ 100). This feature provides dramatically improved noise when compared to state-of-the-art chopper-stabilized amplifiers. 0.1mV/div 1s/div G ≥ 100 Figure 8-1. 0.1-Hz to 10-Hz Input-Referred Voltage Noise 8.4 Device Functional Modes The INA12x have a single functional mode and operate when the power-supply voltage is greater than 4.5 V (±2.25 V). The maximum power-supply voltage for the INA12x is 36 V (±18 V). Submit Document Feedback Copyright © 2022 Texas Instruments Incorporated Product Folder Links: INA128 INA129 13 INA128, INA129 www.ti.com SBOS051F – OCTOBER 1995 – REVISED MAY 2022 9 Application and Implementation Note Information in the following applications sections is not part of the TI component specification, and TI does not warrant its accuracy or completeness. TI’s customers are responsible for determining suitability of components for their purposes, as well as validating and testing their design implementation to confirm system functionality. 9.1 Application Information The INA12x measure a small differential voltage with a high common-mode voltage developed between the noninverting and inverting input. The high input-voltage protection circuit in conjunction with high input impedance make the INA12x an excellent choice for a wide range of applications. The ability to set the reference pin to adjust the functionality of the output signal offers additional flexibility that is practical for multiple configurations. 9.1.1 Input Common-Mode Range The linear input voltage range of the INA12x input circuitry ranges from approximately 2 V less than the positive supply voltage to 2 V greater than the negative supply. A differential input voltage causes the output voltage to increase; however, the linear input range is limited by the output voltage swing of amplifiers A1 and A2. Thus, the linear common-mode input range is related to the output voltage of the complete amplifier. This behavior also depends on the supply voltage (see Figure 7-6). Input overload can produce an output voltage that appears normal. For example, if an input-overload condition drives both input amplifiers to their positive output swing limit, the difference voltage measured by the output amplifier is near zero. The output of A3 is near 0 V even though both inputs are overloaded. 14 Submit Document Feedback Copyright © 2022 Texas Instruments Incorporated Product Folder Links: INA128 INA129 INA128, INA129 www.ti.com SBOS051F – OCTOBER 1995 – REVISED MAY 2022 9.2 Typical Application Figure 9-1 shows the basic connections required for operation of the INA12x. Applications with noisy or high impedance power supplies may require decoupling capacitors close to the device pins as shown. The output is referred to the output reference (REF) pin, which is normally grounded. This connection must be low-impedance to provide good common-mode rejection. A resistance of 8 Ω in series with the REF pin causes a typical device to degrade to approximately 80 dB CMR (G = 1). V+ 0.1µF INA129: INA128: G= 1+ 50 k
RG G =1 + INA128 DESIRED GAIN (V/V) 1 2 5 10 20 50 100 200 500 1000 2000 5000 10000 RG () NC 50.00k 12.50k 5.556k 2.632k 1.02k 505.1 251.3 100.2 50.05 25.01 10.00 5.001 49.4 k RG 7 INA128, INA129 INA129 NEAREST 1% RG () NC 49.9k 12.4k 5.62k 2.61k 1.02k 511 249 100 49.9 24.9 10 4.99 RG ( ) VIN– NEAREST 1% RG () NC 49.4k 12.35k 5489 2600 1008 499 248 99 49.5 24.7 9.88 4.94 2 Overvoltage Protection A1 1 NC 49.9k 12.4k 5.49k 2.61k 1k 499 249 100 49.9 24.9 9.76 4.87 40 k (1) 25 k VO = G • (VIN+ – VIN– ) + VREF + (1) 25 k 8 VIN+ 6 A3 RG 3 40 k Load A2 Overvoltage Protection 40 k (1) INA129: 24.7 k. 4 40 k 5 Ref VREF VO  0.1 µF NC: No Connection VIN– Also drawn in simplified form: VIN+ RG INA128 VO V Ref Figure 9-1. Basic Connections 9.2.1 Design Requirements The devices are configured to monitor the input differential voltage when the input signal gain is set by the external resistor, RG. The output signal is developed with respect to the voltage on the reference pin, REF. The most common application is where the output is referenced to ground when no input signal is present by connecting the REF pin to ground, as Figure 9-1 shows. In single-supply operation, offsetting the output signal to a precise midsupply level is useful (for example, 2.5 V in a 5-V supply environment). To accomplish this level shift, a voltage source must be connected to the REF pin to level shift the output so that the device can drive a single-supply ADC. Voltage reference devices are an excellent option for providing a low-impedance voltage source for the reference pin. However, if a resistor voltage divider is used to generate a reference voltage, the voltage must be buffered by an op amp to avoid CMRR degradation. Submit Document Feedback Copyright © 2022 Texas Instruments Incorporated Product Folder Links: INA128 INA129 15 INA128, INA129 www.ti.com SBOS051F – OCTOBER 1995 – REVISED MAY 2022 9.2.2 Detailed Design Procedure 9.2.2.1 Setting the Gain The gain (G) is set by connecting a single external resistor, RG, between pins 1 and 8: INA128: G = 1 + 50 kΩ / RG (1) INA129: G = 1 + 49.4 kΩ / RG (2) Commonly used gains and resistor values are shown in Figure 9-1. The 50-kΩ term in Equation 1 and the 49.4-kΩ term in Equation 2 come from the sum of the two internal feedback resistors of A1 and A2. These on-chip metal film resistors are laser trimmed to accurate, absolute values. The accuracy and temperature coefficient of these internal resistors are included in the gain accuracy and drift specifications in the Electrical Characteristics table. The stability and temperature drift of the external gain setting resistor, RG, also affects gain. The contribution of RG to gain accuracy and drift can be directly inferred from Equation 1 and Equation 2. Low resistor values required for high gain can make wiring resistance important. Sockets add to the wiring resistance, which contributes additional gain error (possibly an unstable gain error) in gains of approximately 100 or greater. 9.2.2.2 Dynamic Performance The typical performance curve in Figure 7-1 shows that despite low quiescent current, the INA12x achieve wide bandwidth even at high gain. This performance is due to the current-feedback topology of the input stage circuitry. Settling time also remains excellent at high gain. 9.2.2.3 Offset Trimming The INA12x is laser trimmed for low-offset voltage and low offset voltage drift. Most applications require no external offset adjustment. Figure 9-2 shows an optional circuit for trimming the output offset voltage. The voltage applied to the REF pin is summed with the output. The op-amp buffer provides low impedance at the REF pin to preserve good common-mode rejection. V− IN V+ RG + VIN INA128 VO 100µA 1/2 REF200 Ref OPA177 ±10mV Adjustment Range 10kΩ 100Ω 100Ω 100µA 1/2 REF200 V− Figure 9-2. Optional Trimming of Output Offset Voltage 16 Submit Document Feedback Copyright © 2022 Texas Instruments Incorporated Product Folder Links: INA128 INA129 INA128, INA129 www.ti.com SBOS051F – OCTOBER 1995 – REVISED MAY 2022 9.2.2.4 Input Bias Current Return Path The input impedance of the INA12x is extremely high: approximately 10 GΩ. However, a path must be provided for the input bias current of both inputs. This input bias current is approximately ±2 nA. High input impedance means that this input bias current changes very little with varying input voltage. Input circuitry must provide a path for this input bias current for proper operation. Figure 9-3 shows various provisions for an input bias current path. Without a bias current path, the inputs float to a potential that exceeds the common-mode range, and the input amplifiers saturate. If the differential source resistance is low, the bias current return path can be connected to one input (see the thermocouple example in Figure 9-3). With higher source impedance, use two equal resistors to provide a balanced input, with possible advantages of lower input offset voltage due to bias current, and better highfrequency common-mode rejection. For more details about why a valid input bias current return path is necessary, see the Importance of Input Bias Current Return Paths in Instrumentation Amplifier Applications application note. Microphone, Hydrophone etc. INA128 47kΩ 47kΩ Thermocouple INA128 10kΩ INA128 Center−tap provides bias current return. Figure 9-3. Providing an Input Common-Mode Current Path Submit Document Feedback Copyright © 2022 Texas Instruments Incorporated Product Folder Links: INA128 INA129 17 INA128, INA129 www.ti.com SBOS051F – OCTOBER 1995 – REVISED MAY 2022 9.2.3 Application Curves G=1 G = 10 0 20mV/div 20mV/div G = 10 G = 10 0 0 20ms/div 5ms/div G = 100, 1000 G = 1, 10 Figure 9-5. Small Signal Amplitude (2 V/div) Input, G = 1 Output, G = 1 Input, G = 10 Output, G = 10 Amplitude (2 V/div) Figure 9-4. Small Signal Input Step (Not to Scale) Output, G = 100 Output, G = 1000 Time (10 s/div) Time (10 s/div) G = 1, 10 G = 100, 1000 Figure 9-6. Large Signal 18 Figure 9-7. Large Signal Submit Document Feedback Copyright © 2022 Texas Instruments Incorporated Product Folder Links: INA128 INA129 INA128, INA129 www.ti.com SBOS051F – OCTOBER 1995 – REVISED MAY 2022 9.3 System Examples +5V 2.5V − ∆V RG 300Ω VO INA128 Ref 2.5V + ∆V Figure 9-8. Bridge Amplifier − VIN + RG VO INA128 Ref R1 1MΩ C1 0.1µF 1 f−3dB= 2πR1C1 OPA130 = 1.59Hz Figure 9-9. AC-Coupled Instrumentation Amplifier V+ +10V 6 REF102 R1 2 R2 4 Pt100 Cu K Cu RG INA128 Ref R3 100
= Pt100 at 0°C ISA TYPE E J K T MATERIAL + Chromel  Constantan + Iron  Constantan + Chromel  Alumel + Copper  Constantan VO SEEBECK COEFICIENT (µV/°C) R1, R2 58.5 66.5 k 50.2 76.8 k 39.4 97.6 k 38.0 102 k Figure 9-10. Thermocouple Amplifier With RTD Cold-Junction Compensation Submit Document Feedback Copyright © 2022 Texas Instruments Incorporated Product Folder Links: INA128 INA129 19 INA128, INA129 www.ti.com SBOS051F – OCTOBER 1995 – REVISED MAY 2022
IO = R1 VIN RG INA128 V IN • G R1 + Ref IB A1 A1 IB ERROR OPA177 ±1.5 nA OPA131 ±50 pA OPA602 ±1 pA OPA128 ±75 fA IO Load Figure 9-11. Differential Voltage to Current Converter RG = 5.6kΩ 2.8kΩ G = 10 LA RA RG/2 INA128 VO Ref 2.8kΩ 390kΩ 1/2 OPA2131 RL 390kΩ VG 10kΩ VG 1/2 OPA2131 NOTE: Due to the INA128’s current-feedback topology, VG is approximately 0.7V less than the common-mode input voltage. This DC offset in this guard potential is satisfactory for many guarding applications. Figure 9-12. ECG Amplifier With Right-Leg Drive 20 Submit Document Feedback Copyright © 2022 Texas Instruments Incorporated Product Folder Links: INA128 INA129 INA128, INA129 www.ti.com SBOS051F – OCTOBER 1995 – REVISED MAY 2022 10 Power Supply Recommendations The minimum power supply voltage for INA12x is ±2.25 V and the maximum power supply voltage is ±18 V. This minimum and maximum range covers a wide range of power supplies; but for optimum performance, ±15 V is recommended. Add a bypass capacitor at the input to compensate for the layout and power supply source impedance. 10.1 Low-Voltage Operation The INA12x operate on power supplies as low as ±2.25 V. Performance remains excellent with power supplies ranging from ±2.25 V to ±18 V. Most parameters vary only slightly throughout this supply voltage range; see Section 7.6. Operation at very-low supply voltages requires careful attention to make sure that the input voltages remain within the linear range. Voltage swing requirements of internal nodes limit the input common-mode range with low power-supply voltage. Figure 7-6 shows the range of linear operation for ±15-V, ±5-V, and ±2.5-V supplies. 11 Layout 11.1 Layout Guidelines Place the power-supply bypass capacitor as close as possible to the supply and ground pins. The recommended value of this bypass capacitor is 0.1 μF to 1 μF. If necessary, add more decoupling capacitance to compensate for noisy or high-impedance power supplies. These decoupling capacitors must be placed between the power supply and INA12x devices. The gain resistor must be placed close to pin 1 and pin 8. This placement limits the layout loop and minimizes any noise coupling into the devices. 11.2 Layout Example Gain Resistor Bypass Capacitor VIN VIN – + R6 R6 VIH– V+ VIH+ VO V– REF V+ VOUT GND Bypass Capacitor V– GND Figure 11-1. Recommended Layout Submit Document Feedback Copyright © 2022 Texas Instruments Incorporated Product Folder Links: INA128 INA129 21 INA128, INA129 www.ti.com SBOS051F – OCTOBER 1995 – REVISED MAY 2022 12 Device and Documentation Support 12.1 Device Support 12.1.1 Development Support 12.1.1.1 PSpice® for TI PSpice® for TI is a design and simulation environment that helps evaluate performance of analog circuits. Create subsystem designs and prototype solutions before committing to layout and fabrication, reducing development cost and time to market. 12.1.1.2 TINA-TI™ Simulation Software (Free Download) TINA-TI™ simulation software is a simple, powerful, and easy-to-use circuit simulation program based on a SPICE engine. TINA-TI simulation software is a free, fully-functional version of the TINA™ software, preloaded with a library of macromodels, in addition to a range of both passive and active models. TINA-TI simulation software provides all the conventional dc, transient, and frequency domain analysis of SPICE, as well as additional design capabilities. Available as a free download from the Analog eLab Design Center, TINA-TI simulation software offers extensive post-processing capability that allows users to format results in a variety of ways. Virtual instruments offer the ability to select input waveforms and probe circuit nodes, voltages, and waveforms, creating a dynamic quick-start tool. Note These files require that either the TINA software or TINA-TI software be installed. Download the free TINA-TI simulation software from the TINA-TI™ software folder. 12.2 Documentation Support 12.2.1 Related Documentation For related documentation see the following: • Texas Instruments, Comprehensive Error Calculation for Instrumentation Amplifiers application note • Texas Instruments, Importance of Input Bias Current Return Paths in Instrumentation Amplifier Applications application note 12.3 Receiving Notification of Documentation Updates To receive notification of documentation updates, navigate to the device product folder on ti.com. Click on Subscribe to updates to register and receive a weekly digest of any product information that has changed. For change details, review the revision history included in any revised document. 12.4 Support Resources TI E2E™ support forums are an engineer's go-to source for fast, verified answers and design help — straight from the experts. Search existing answers or ask your own question to get the quick design help you need. Linked content is provided "AS IS" by the respective contributors. They do not constitute TI specifications and do not necessarily reflect TI's views; see TI's Terms of Use. 12.5 Trademarks TINA-TI™ and TI E2E™ are trademarks of Texas Instruments. TINA™ is a trademark of DesignSoft, Inc. PSpice® is a registered trademark of Cadence Design Systems, Inc. All trademarks are the property of their respective owners. 22 Submit Document Feedback Copyright © 2022 Texas Instruments Incorporated Product Folder Links: INA128 INA129 INA128, INA129 www.ti.com SBOS051F – OCTOBER 1995 – REVISED MAY 2022 12.6 Electrostatic Discharge Caution This integrated circuit can be damaged by ESD. Texas Instruments recommends that all integrated circuits be handled with appropriate precautions. Failure to observe proper handling and installation procedures can cause damage. ESD damage can range from subtle performance degradation to complete device failure. Precision integrated circuits may be more susceptible to damage because very small parametric changes could cause the device not to meet its published specifications. 12.7 Glossary TI Glossary This glossary lists and explains terms, acronyms, and definitions. 13 Mechanical, Packaging, and Orderable Information The following pages include mechanical, packaging, and orderable information. This information is the most current data available for the designated devices. This data is subject to change without notice and revision of this document. For browser-based versions of this data sheet, refer to the left-hand navigation. Submit Document Feedback Copyright © 2022 Texas Instruments Incorporated Product Folder Links: INA128 INA129 23 PACKAGE OPTION ADDENDUM www.ti.com 28-May-2022 PACKAGING INFORMATION Orderable Device Status (1) Package Type Package Pins Package Drawing Qty Eco Plan (2) Lead finish/ Ball material MSL Peak Temp Op Temp (°C) Device Marking (3) Samples (4/5) (6) INA128P ACTIVE PDIP P 8 50 RoHS & Green Call TI N / A for Pkg Type INA128P Samples INA128PA ACTIVE PDIP P 8 50 RoHS & Green Call TI N / A for Pkg Type INA128P A Samples INA128PG4 ACTIVE PDIP P 8 50 RoHS & Green Call TI N / A for Pkg Type INA128P Samples INA128U ACTIVE SOIC D 8 75 RoHS & Green Call TI Level-3-260C-168 HR INA 128U Samples INA128U/2K5 ACTIVE SOIC D 8 2500 RoHS & Green Call TI Level-3-260C-168 HR INA 128U Samples INA128U/2K5G4 ACTIVE SOIC D 8 2500 RoHS & Green Call TI Level-3-260C-168 HR INA 128U Samples INA128UA ACTIVE SOIC D 8 75 RoHS & Green NIPDAU Level-3-260C-168 HR -40 to 125 INA 128U A INA128UA/2K5 ACTIVE SOIC D 8 2500 RoHS & Green Call TI Level-3-260C-168 HR -40 to 125 INA 128U A INA128UA/2K5E4 ACTIVE SOIC D 8 2500 RoHS & Green Call TI Level-3-260C-168 HR -40 to 125 INA 128U A INA128UA/2K5G4 ACTIVE SOIC D 8 2500 RoHS & Green Call TI Level-3-260C-168 HR -40 to 125 INA 128U A INA128UAE4 ACTIVE SOIC D 8 75 RoHS & Green NIPDAU Level-3-260C-168 HR -40 to 125 INA 128U A INA128UAG4 ACTIVE SOIC D 8 75 RoHS & Green NIPDAU Level-3-260C-168 HR -40 to 125 INA 128U A INA128UG4 ACTIVE SOIC D 8 75 RoHS & Green Call TI Level-3-260C-168 HR INA129P ACTIVE PDIP P 8 50 RoHS & Green Call TI INA129PA ACTIVE PDIP P 8 50 RoHS & Green Call TI Addendum-Page 1 Samples Samples Samples Samples Samples Samples INA 128U Samples N / A for Pkg Type INA129P Samples N / A for Pkg Type INA129P Samples PACKAGE OPTION ADDENDUM www.ti.com 28-May-2022 Orderable Device Status (1) Package Type Package Pins Package Drawing Qty Eco Plan (2) Lead finish/ Ball material MSL Peak Temp Op Temp (°C) Device Marking (3) Samples (4/5) (6) A INA129PG4 ACTIVE PDIP P 8 50 RoHS & Green Call TI N / A for Pkg Type INA129P Samples INA129U ACTIVE SOIC D 8 75 RoHS & Green Call TI Level-3-260C-168 HR INA 129U Samples INA129U/2K5 ACTIVE SOIC D 8 2500 RoHS & Green Call TI Level-3-260C-168 HR INA 129U Samples INA129UA ACTIVE SOIC D 8 75 RoHS & Green NIPDAU Level-3-260C-168 HR -40 to 125 INA 129U A INA129UA/2K5 ACTIVE SOIC D 8 2500 RoHS & Green Call TI Level-3-260C-168 HR -40 to 125 INA 129U A INA129UA/2K5G4 ACTIVE SOIC D 8 2500 RoHS & Green Call TI Level-3-260C-168 HR -40 to 125 INA 129U A INA129UAE4 ACTIVE SOIC D 8 75 RoHS & Green NIPDAU Level-3-260C-168 HR -40 to 125 INA 129U A (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