INA128UA/2K5

Order Now Product Folder Support & Community Tools & Software Technical Documents Reference Design INA128, INA129 SBOS051E – OCTOBER 1995 – REVISED APRIL 2019 INA12x Precision, Low-Power Instrumentation Amplifiers A newer version of this device is now available: INA828 1 Features 3 Description • The INA128 and INA129 are low-power, general purpose instrumentation amplifiers offering excellent accuracy. The versatile 3-op amp design and small size make these amplifiers ideal for a wide range of applications. Current-feedback input circuitry provides wide bandwidth even at high gain (200 kHz at G = 100). 1 • • • • • • • • A newer version of this device is now available: INA828 Low offset voltage: 50 μV maximum Low drift: 0.5 μV/°C maximum Low Input Bias Current: 5 nA maximum High CMR: 120 dB minimum 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; the INA129 gain equation is compatible with the AD620. The INA12x is available in 8-pin plastic DIP and SO-8 surface-mount packages, specified for the –40°C to +85°C temperature range. The INA128 is also available in a dual configuration, the INA2128. 2 Applications • • • • • Bridge amplifier Thermocouple amplifier RTD sensor amplifier Medical instrumentation Data acquisition The upgraded INA828 offers a lower input bias current (0.6 nA maximum) 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(1) PART NUMBER INA128, INA129 PACKAGE BODY SIZE (NOM) SOIC (8) 3.91 mm × 4.90 mm PDIP (8) 6.35 mm × 9.81 mm (1) For all available packages, see the package option addendum at the end of the data sheet. Simplified Schematic V+ 7 2 − VIN INA128: INA128, INA129 G=1+ Over-Voltage Protection A1 40kΩ 1 G=1+ A3 8 + VIN 3 INA129: 40kΩ 25k (1) RG 50kΩ RG 6 49.4kΩ RG VO 25kΩ(1) Over-Voltage Protection 5 A2 Ω NOTE: (1) INA129: 24.7kΩ 40kΩ Ref 40kΩ 4 V− 1 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. A newer version of this device is now available: INA828 INA128, INA129 SBOS051E – OCTOBER 1995 – REVISED APRIL 2019 www.ti.com Table of Contents 1 2 3 4 5 6 7 8 Features .................................................................. Applications ........................................................... Description ............................................................. Revision History..................................................... Device Comparison Table..................................... Pin Configuration and Functions ......................... Specifications......................................................... 1 1 1 2 3 4 4 7.1 7.2 7.3 7.4 7.5 7.6 4 4 5 5 5 8 Absolute Maximum Ratings ...................................... ESD Ratings.............................................................. Recommended Operating Conditions....................... Thermal Information .................................................. Electrical Characteristics........................................... Typical Characteristics .............................................. Detailed Description ............................................ 12 8.1 Overview ................................................................. 12 8.2 Functional Block Diagram ....................................... 12 8.3 Feature Description................................................. 12 8.4 Device Functional Modes........................................ 13 9 Application and Implementation ........................ 14 9.1 Application Information............................................ 14 9.2 Typical Application ................................................. 14 10 Power Supply Recommendations ..................... 18 10.1 Low Voltage Operation ......................................... 18 11 Layout................................................................... 20 11.1 Layout Guidelines ................................................. 20 11.2 Layout Example .................................................... 20 12 Device and Documentation Support ................. 21 12.1 12.2 12.3 12.4 12.5 12.6 Related Links ........................................................ Receiving Notification of Documentation Updates Community Resources.......................................... Trademarks ........................................................... Electrostatic Discharge Caution ............................ Glossary ................................................................ 21 21 21 21 21 21 13 Mechanical, Packaging, and Orderable Information ........................................................... 21 4 Revision History NOTE: Page numbers for previous revisions may differ from page numbers in the current version. Changes from Revision D (January 2018) to Revision E Page • Added information about the newer, upgraded INA828 ......................................................................................................... 1 • Added Device Comparison Table .......................................................................................................................................... 3 Changes from Revision C (October 2015) to Revision D 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 ........................................................................................................................................................................ 5 Changes from Revision B (February 2005) to Revision C • 2 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 Documentation Feedback Copyright © 1995–2019, Texas Instruments Incorporated Product Folder Links: INA128 INA129 A newer version of this device is now available: INA828 INA128, INA129 www.ti.com SBOS051E – OCTOBER 1995 – REVISED APRIL 2019 5 Device Comparison Table DEVICE GAIN EQUATION RG PINS AT PIN INA828 50-µV Offset, 0.5 µV/°C VOS drift, 7-nV/√Hz Noise, Low-Power, Precision Instrumentation Amplifier DESCRIPTION G = 1 + 50 kΩ / RG 1, 8 INA819 35-µV Offset, 0.4 µV/°C VOS drift, 8-nV/√Hz Noise, Low-Power, Precision Instrumentation Amplifier G = 1 + 50 kΩ / RG 2, 3 INA821 35-µV Offset, 0.4 µV/°C VOS drift, 7-nV/√Hz Noise, HighBandwidth, Precision Instrumentation Amplifier G = 1 + 49.4 kΩ / RG 2, 3 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 Submit Documentation Feedback Copyright © 1995–2019, Texas Instruments Incorporated Product Folder Links: INA128 INA129 3 A newer version of this device is now available: INA828 INA128, INA129 SBOS051E – OCTOBER 1995 – REVISED APRIL 2019 www.ti.com 6 Pin Configuration and Functions D and P Packages 8-Pin SOIC and PDIP Top View RG 1 8 RG IN 2 7 V+ V+IN 3 6 VO V− 4 5 Ref V − Pin Functions PIN NAME NO. REF I/O DESCRIPTION 5 I RG 1,8 — Reference input. This pin must be driven by low impedance or connected to ground. Gain setting pin. For gains greater than 1, place a gain resistor between pin 1 and pin 8. V- 4 — Negative supply V+ 7 — Positive supply VIN- 2 I Negative input VIN+ 3 I Positive input VO 6 I Output 7 Specifications 7.1 Absolute Maximum Ratings over operating free-air temperature range (unless otherwise noted) (1) MIN MAX UNIT Supply voltage ±18 V Analog input voltage ±40 V Output short circuit (to ground) continuous Operating temperature –40 125 °C Junction temperature 150 °C Lead temperature (soldering, 10 seconds) 300 °C 125 °C Storage temperature, Tstg (1) –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. 7.2 ESD Ratings VALUE V(ESD) (1) (2) 4 Electrostatic discharge Human-body model (HBM), per ANSI/ESDA/JEDEC JS-001 (1) Charged-device model (CDM), per JEDEC specification JESD22-C101 (2) ±2000 ±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. Submit Documentation Feedback Copyright © 1995–2019, Texas Instruments Incorporated Product Folder Links: INA128 INA129 A newer version of this device is now available: INA828 INA128, INA129 www.ti.com SBOS051E – OCTOBER 1995 – REVISED APRIL 2019 7.3 Recommended Operating Conditions over operating free-air temperature range (unless otherwise noted) V power supply Input common-mode voltage range for VO = 0 MIN NOM ±2.25 ±15 MAX UNIT ±18 V V–2V V + –2 V TA operating temperature INA128-HT –55 175 °C TA operating temperature INA129-HT –55 210 °C 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. 7.5 Electrical Characteristics at TA = 25°C, VS = ±15 V, and RL = 10 kΩ (unless otherwise noted) PARAMETER TEST CONDITIONS MIN TYP MAX INA128P, U INA129P, U ±10±100/G ±50±500/G INA128PA, UA INA129PA, UA ±25±100/G ±125±1000/G INA128P, U INA129P, U ±0.2±2/G ±0.5±20/G INA128PA, UA INA129PA, UA ±0.2±5/G ±1±20/G ±0.2±20/G ±1±100/G UNIT INPUT Initial Offset voltage, RTI vs temperature vs power supply TA = 25°C TA = TMIN to TMAX VS = ±2.25 V to ±18 V µV µV/°C INA128P, U INA129P, U µV/V INA128PA, UA INA129PA, UA ±2±200/G Long-term stability ±0.1±3/g Differential 1010 || 2 Common mode 1011 || 9 Impedance Common-mode voltage range (1) VO = 0 V (V+) - 2 (V+) - 1.4 (V…) + 2 (V–) + 1.7 Safe input voltage (1) µV/mo Ω || pF V ±40 V Input common-mode range varies with output voltage; see Typical Characteristics. Submit Documentation Feedback Copyright © 1995–2019, Texas Instruments Incorporated Product Folder Links: INA128 INA129 5 A newer version of this device is now available: INA828 INA128, INA129 SBOS051E – OCTOBER 1995 – REVISED APRIL 2019 www.ti.com Electrical Characteristics (continued) at TA = 25°C, VS = ±15 V, and RL = 10 kΩ (unless otherwise noted) PARAMETER TEST CONDITIONS G=1 G = 10 Common-mode rejection VCM = ±13 V, ΔRS = 1 kΩ G = 100 G = 1000 MIN TYP INA128P, U INA129P, U 80 86 INA128PA, UA INA129PA, UA 73 INA128P, U INA129P, U INA128PA, UA INA129PA, UA 100 93 dB INA128P, U INA129P, U 120 INA128PA, UA INA129PA, UA 110 INA128P, U INA129P, U 120 INA128PA, UA INA129PA, UA 110 125 130 ±2 ±10 Bias current vs temperature ±30 INA128P, U INA129P, U ±1 Noise current f = 1 kHz ±5 ±10 ±30 f = 10 Hz f = 100 Hz pA/°C nA INA128PA, UA INA129PA, UA Offset current vs temperature Noise voltage, RTI ±5 nA INA128PA, UA INA129PA, UA Offset current UNIT 106 INA128P, U INA129P, U Bias current MAX pA/°C 10 8 G = 1000, RS = 0Ω nV/√Hz 8 fB = 0.1 Hz to 10 Hz 0.2 f = 10 Hz 0.9 f = 1 kHz 0.3 FB = 0.1 Hz to 10 Hz 30 µVPP pA/√Hz pAPP GAIN (2) Gain equation INA128 1 + (50 kΩ/RG) INA129 1 + (49.4 kΩ/RG) Range of gain 1 G=1 G = 10 Gain error G = 100 G = 1000 (2) 6 INA128P, U INA129P, U V/V 10000 ±0.01% INA128PA, UA INA129PA, UA V/V ±0.024% ±0.01% INA128P, U INA129P, U ±0.02% INA128PA, UA INA129PA, UA ±0.4% ±0.5% INA128P, U INA129P, U ±0.05% INA128PA, UA INA129PA, UA ±0.5% ±0.7% INA128P, U INA129P, U ±0.5% INA128PA, UA INA129PA, UA ±1% ±2% Nonlinearity measurements in G = 1000 are dominated by noise. Typical non-linearity is ±0.001%. Submit Documentation Feedback Copyright © 1995–2019, Texas Instruments Incorporated Product Folder Links: INA128 INA129 A newer version of this device is now available: INA828 INA128, INA129 www.ti.com SBOS051E – OCTOBER 1995 – REVISED APRIL 2019 Electrical Characteristics (continued) at TA = 25°C, VS = ±15 V, and RL = 10 kΩ (unless otherwise noted) PARAMETER Gain vs temperature (3) TEST CONDITIONS 50-kΩ (or 49.4-kΩ) Resistance (3) (4) VO = ±13.6 V, G = 1 INA128P, U INA129P, U TYP MAX ±1 ±10 ±25 ±100 ±0.0001 ±0.001 INA128PA, UA INA129PA, UA ±0.0003 INA128PA, UA INA129PA, UA ppm/°C ±0.002 ±0.004 INA128P, U INA129P, U G = 100 UNIT ±0.002 INA128P, U INA129P, U G = 10 Nonlinearity MIN G=1 ±0.0005 INA128PA, UA INA129PA, UA % of FSR ±0.002 ±0.004 G = 1000 ±0.001 /> OUTPUT (2) Voltage Positive RL = 10 kΩ (V+) – 1.4 (V+) – 0.9 Negative RL = 10 kΩ (V–) + 1.4 (V–) + 0.8 V Load capacitance stability 1000 pF Short-circuit current 6/–15 mA G=1 1.3 MHz G = 10 700 G = 100 200 G = 1000 20 FREQUENCY RESPONSE Bandwidth, –3 dB Slew rate Settling time, 0.01% Overload recovery VO = ±10 V, G = 10 4 G=1 7 G = 10 7 G = 100 9 G = 1000 80 50% overdrive kHz V/µs µs 4 µs POWER SUPPLY Voltage range Current, total ±2.25 VIN = 0 V ±15 ±18 V ±700 ±750 µA TEMPERATURE RANGE Specification –40 85 °C Operating –40 125 °C (3) (4) Specified by wafer test. Temperature coefficient of the 50 kΩ (or 49.4 kΩ) term in the gain equation. Submit Documentation Feedback Copyright © 1995–2019, Texas Instruments Incorporated Product Folder Links: INA128 INA129 7 A newer version of this device is now available: INA828 INA128, INA129 SBOS051E – OCTOBER 1995 – REVISED APRIL 2019 www.ti.com 7.6 Typical Characteristics at TA = 25°C and VS = ±15 V (unless otherwise noted) 60 140 G = 1000V/V G = 100V/V G = 1000V/V Common−Mode Rejection (dB) 50 40 Gain (dB) G = 100V/V 30 20 G = 10V/V 10 0 G = 1V/V − 10 − 20 120 G = 10V/V 100 G = 1V/V 80 60 40 20 0 1k 10k 100k 1M 10M 10 100 1k Frequency (Hz) 100k 10k 1M Frequency (Hz) Figure 1. Gain vs Frequency Figure 2. Common-Mode Rejection vs Frequency 140 140 Power Supply Rejection (dB) Power Supply Rejection (dB) G = 1000V/V 120 G = 1000V/V 100 G = 100V/V 80 60 G = 10V/V 40 G = 1V/V 20 0 10 100 1k 10k 100k G = 100V/V 100 80 60 G = 10V/V 40 G = 1V/V 20 0 10 1M 100 10k 100k 1M Frequency (Hz) Figure 3. Positive Power Supply Rejection vs Frequency Figure 4. Negative Power Supply Rejection vs Frequency 5 G ≥ 10 G ≥ 10 Common−Mode Voltage (V) G=1 G=1 5 VD/2 0 VD/2 + −5 VCM +15V − + VO − Ref + − 15V −10 3 2 −15 −15 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 8 1k Frequency (Hz) 15 Common−Mode Voltage (V) 120 −5 −10 −5 0 5 10 15 −5 −4 −3 −2 −1 0 1 2 3 4 5 Output Voltage (V) Output Voltage (V) Figure 5. Input Common-Mode Range vs Output Voltage, VS = ±15 V Figure 6. Input Common-Mode Range vs Output Voltage, VS = ±5 V, ±2.5 V Submit Documentation Feedback Copyright © 1995–2019, Texas Instruments Incorporated Product Folder Links: INA128 INA129 A newer version of this device is now available: INA828 INA128, INA129 www.ti.com SBOS051E – OCTOBER 1995 – REVISED APRIL 2019 Typical Characteristics (continued) 100 100 ) 1k 10 100 G = 10V/V 1 10 G = 100, 1000V/V Current Noise 0.01% Settling Time (ms) G = 1V/V Input Bias Current Noise (pA/ Input-Referred Voltage Noise (nV/√Hz) at TA = 25°C and VS = ±15 V (unless otherwise noted) 0.1 1 1 10 100 0.1% 10 1 10k 1k 1 10 100 1000 Gain (V/V) Frequency (Hz) Figure 7. Input-Referred Noise vs Frequency Figure 8. Settling Time vs Gain 0.85 6 0.8 5 5 Slew Rate 0.7 3 IQ 0.65 Input Current (mA) 4 0.75 3 Slew Rate (V/µs) Quiescent Current (µA) 4 2 Flat region represents normal linear operation. 2 G = 1V/V 0 −1 −50 −25 0 25 50 Temperature (°C) 75 100 +15V G = 1V/V −2 −3 −5 −50 1 125 VIN G = 1000V/V −4 06 −75 G = 1000V/V 1 −40 0 −30 −20 −10 IIN −15V 10 20 30 40 50 Input Voltage (V) Figure 9. Quiescent Current and Slew Rate vs Temperature Figure 10. Input Overvoltage V/I Characteristics 10 2 6 Input Bias Current (nA) Offset Voltage Change (µV) 8 4 2 0 −2 −4 1 IOS 0 IB −1 Typical IB and IOS Range ±2nA at 25°C −6 −8 −10 0 100 200 300 400 500 −2 −75 −50 −25 0 25 50 75 100 125 Time (µs) Temperature (°C) Figure 11. Input Offset Voltage Warm-Up Figure 12. Input Bias Current vs Temperature Submit Documentation Feedback Copyright © 1995–2019, Texas Instruments Incorporated Product Folder Links: INA128 INA129 9 A newer version of this device is now available: INA828 INA128, INA129 SBOS051E – OCTOBER 1995 – REVISED APRIL 2019 www.ti.com 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 (V−) (V−) 0 1 2 3 Output Voltage Swing (V) (V+) (V+)−0.4 Output Voltage Swing (V) Output Voltage (V) at TA = 25°C and VS = ±15 V (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 4 (V−) Output Current (mA) 0 5 10 15 20 Power Supply Voltage (V) Figure 13. Output Voltage Swing vs Output Current Figure 14. Output Voltage Swing vs Power Supply Voltage 18 Short−Circuit Current (mA) Peak−to−Peak Output Voltage (VPP) 30 16 −ISC 14 12 10 8 6 +ISC 4 2 0 G = 10, 100 25 G=1 G = 1000 20 15 10 5 0 −75 −50 0 −25 25 50 75 100 125 1k 10k 100k 1M Temperature (°C) Frequency (Hz) Figure 15. Short Circuit Output Current vs Temperature Figure 16. Maximum Output Voltage vs Frequency 1 THD + N (%) VO = 1Vrms 500kHz Measurement Bandwidth 0.1 G=1 RL = 10kΩ G=1 G = 100, RL = 100kΩ 20mV/div 0.01 G = 1, RL = 100kΩ Dashed Portion is noise limited. 0.001 100 1k 10k G = 10V/V RL = 100kΩ G = 10 100k 5µs/div Frequency (Hz) Figure 17. Total Harmonic Distortion + Noise vs Frequency 10 Submit Documentation Feedback Figure 18. Small Signal (G = 1, 10) Copyright © 1995–2019, Texas Instruments Incorporated Product Folder Links: INA128 INA129 A newer version of this device is now available: INA828 INA128, INA129 www.ti.com SBOS051E – OCTOBER 1995 – REVISED APRIL 2019 Typical Characteristics (continued) at TA = 25°C and VS = ±15 V (unless otherwise noted) G = 100 G=1 20mV/div 5V/div G = 1000 G = 10 5µs/div 20µs/div Figure 20. Large Signal (G = 1, 10) Figure 19. Small Signal (G = 100, 1000) G = 100 5V/div 0.1µV/div G = 1000 20µs/div 1s/div Figure 21. Large Signal (G = 100, 1000) Figure 22. Voltage Noise 0.1 to 10-Hz Input-Referred, G ≥ 100 Submit Documentation Feedback Copyright © 1995–2019, Texas Instruments Incorporated Product Folder Links: INA128 INA129 11 A newer version of this device is now available: INA828 INA128, INA129 SBOS051E – OCTOBER 1995 – REVISED APRIL 2019 www.ti.com 8 Detailed Description 8.1 Overview The INA12x instrumentation amplifier is a type of differential amplifier that has been outfitted with input protection circuit and input buffer amplifiers, which eliminate the need for input impedance matching and make the amplifier particularly suitable for use in measurement and test equipment. Additional characteristics of the INA128 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 V+ INA128: 7 50 kW RG G=1+ INA128, INA129 2 - VIN Over-Voltage Protection INA129: A1 40 kW 1 G=1+ 40 kW (1) 49.4 kW RG 25 kW 6 A3 RG 8 VO (1) 25 kW + VIN 3 Over-Voltage Protection 5 A2 40 kW Ref 40 kW 4 NOTE: (1) INA129: 24.7 kW V- 8.3 Feature Description The INA12x devices are low power, general-purpose instrumentation amplifiers offering excellent accuracy. The versatile three-operational-amplifier design and small size make the amplifiers ideal 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 INA128 is 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 quiescent current of 2 mA, typically. The internal input protection can withstand up to ±40 V without damage. 12 Submit Documentation Feedback Copyright © 1995–2019, Texas Instruments Incorporated Product Folder Links: INA128 INA129 A newer version of this device is now available: INA828 INA128, INA129 www.ti.com SBOS051E – OCTOBER 1995 – REVISED APRIL 2019 8.4 Device Functional Modes 8.4.1 Noise Performance The INA12x provides very low noise in most applications. Low-frequency noise is approximately 0.2 µVPP measured from 0.1 to 10 Hz (G ≥ 100). This provides dramatically improved noise when compared to state-ofthe-art chopper-stabilized amplifiers. 0.1mV/div 1s/div G ≥ 100 Figure 23. 0.1-Hz to 10-Hz Input-Referred Voltage Noise 8.4.2 Input Common-Mode Range The linear input voltage range of the input circuitry of the INA12x is from approximately 1.4 V below the positive supply voltage to 1.7 V above the negative supply. As a differential input voltage causes the output voltage 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 supply voltage (see performance curve Figure 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 will be near zero. The output of A3 will be near 0 V even though both inputs are overloaded. Submit Documentation Feedback Copyright © 1995–2019, Texas Instruments Incorporated Product Folder Links: INA128 INA129 13 A newer version of this device is now available: INA828 INA128, INA129 SBOS051E – OCTOBER 1995 – REVISED APRIL 2019 www.ti.com 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. Customers should validate and test their design implementation to confirm system functionality. 9.1 Application Information The INA12x measures small differential voltage with 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 suitable 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. 9.2 Typical Application Figure 24 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) terminal which is normally grounded. This must be a low-impedance connection to assure good common-mode rejection. A resistance of 8 Ω in series with the Ref pin will cause a typical device to degrade to approximately 80dB CMR (G = 1). V+ INA129: INA128: G 1 50k RG G INA128 DESIRED GAIN (V/V) 1 2 5 10 20 50 100 200 500 1000 2000 5000 10000 RG (Ω) 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 1 0.1µF 49.4k RG NC 49.9k 12.4k 5.62k 2.61k 1.02k 511 249 100 49.9 24.9 10 4.99 RG (Ω) NC 49.4k 12.35k 5489 2600 1008 499 248 99 49.5 24.7 9.88 4.94 INA128, INA129 − VIN INA129 NEAREST 1% RG (Ω) 7 NEAREST 1% RG (Ω NC 49.9k 12.4k 5.49k 2.61k 1k 499 249 100 49.9 24.9 9.76 4.87 NC: No Connection 2 Over−Voltage Protection A1 40kΩ 1 − + VO = G • (VIN − VIN ) A3 RG 3 6 + 8 + VIN 40kΩ 25kΩ(1) 25kΩ(1) Load VO A2 Over−Voltage Protection 40kΩ NOTE: (1) INA129: 24.7kΩ 4 40kΩ 5 Ref − 0.1µF − V IN V− Also drawn in simplified form: RG + V IN INA128 VO Ref Figure 24. Basic Connections 14 Submit Documentation Feedback Copyright © 1995–2019, Texas Instruments Incorporated Product Folder Links: INA128 INA129 A newer version of this device is now available: INA828 INA128, INA129 www.ti.com SBOS051E – OCTOBER 1995 – REVISED APRIL 2019 Typical Application (continued) 9.2.1 Design Requirements The device can be configured to monitor the input differential voltage when the gain of the input signal is set by the external resistor RG. The output signal references to the Ref pin. 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 24 shows. When the input signal increases, the output voltage at the OUT pin increases, too. 9.2.2 Detailed Design Procedure 9.2.2.1 Setting the Gain Gain is set by connecting a single external resistor, RG, connected between pins 1 and 8: INA128: g = 1 + 50 kΩ/RG (1) Commonly used gains and resistor values are shown in Figure 24. The 50-kΩ term in Equation 1 comes from the sum of the two internal feedback resistors of A1 and A2. These onchip 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 of the INA128. 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. 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 Figure 1 shows that, despite its low quiescent current, the INA12x achieves wide bandwidth even at high gain. This 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 offset voltage drift. Most applications require no external offset adjustment. Figure 25 shows an optional circuit for trimming the output offset voltage. The voltage applied to the Ref terminal is summed with the output. The op amp buffer provides low impedance at the Ref terminal to preserve good common-mode rejection. V− IN V+ RG INA128 VO 100µA 1/2 REF200 Ref + VIN OPA177 ±10mV Adjustment Range 10kΩ 100Ω 100Ω 100µA 1/2 REF200 V− Figure 25. Optional Trimming of Output Offset Voltage 9.2.2.4 Input Bias Current Return Path The input impedance of the INA12x is extremely high: approximately 1010 Ω. 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. Submit Documentation Feedback Copyright © 1995–2019, Texas Instruments Incorporated Product Folder Links: INA128 INA129 15 A newer version of this device is now available: INA828 INA128, INA129 SBOS051E – OCTOBER 1995 – REVISED APRIL 2019 www.ti.com Typical Application (continued) Input circuitry must provide a path for this input bias current for proper operation. Figure 26 shows various provisions for an input bias current path. Without a bias current path, the inputs will float to a potential which exceeds the common-mode range, and the input amplifiers will 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 26). With higher source impedance, using two equal resistors provides a balanced input, with possible advantages of lower input offset voltage due to bias current and better highfrequency common-mode rejection. Microphone, Hydrophone etc. INA128 47kΩ 47kΩ Thermocouple INA128 10kΩ INA128 Center−tap provides bias current return. Figure 26. Providing an Input Common-Mode Current Path 16 Submit Documentation Feedback Copyright © 1995–2019, Texas Instruments Incorporated Product Folder Links: INA128 INA129 A newer version of this device is now available: INA828 INA128, INA129 www.ti.com SBOS051E – OCTOBER 1995 – REVISED APRIL 2019 Typical Application (continued) 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 28. Small Signal Figure 27. Small Signal G=1 G =100 5V/div 5V/div G = 10 G =1000 5ms/div 20ms/div G = 1, 10 G = 100, 1000 Figure 29. Large Signal Figure 30. Large Signal Submit Documentation Feedback Copyright © 1995–2019, Texas Instruments Incorporated Product Folder Links: INA128 INA129 17 A newer version of this device is now available: INA828 INA128, INA129 SBOS051E – OCTOBER 1995 – REVISED APRIL 2019 www.ti.com 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. TI recommends adding a bypass capacitor at the input to compensate for the layout and power supply source impedance. 10.1 Low Voltage Operation The INA12x can be operated 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 Typical Characteristics. Operation at very low supply voltage requires careful attention to assure that the input voltages remain within their linear range. Voltage swing requirements of internal nodes limit the input common-mode range with low power supply voltage. Figure 6 shows the range of linear operation for ±15-V, ±5-V, and ±2.5-V supplies. +5V 2.5V − ∆V RG 300Ω VO INA128 Ref 2.5V + ∆V Figure 31. Bridge Amplifier − VIN + RG VO INA128 Ref C1 0.1µF OPA130 R1 1MΩ 1 f−3dB= 2πR1C1 = 1.59Hz Figure 32. AC-Coupled Instrumentation Amplifier 18 Submit Documentation Feedback Copyright © 1995–2019, Texas Instruments Incorporated Product Folder Links: INA128 INA129 A newer version of this device is now available: INA828 INA128, INA129 www.ti.com SBOS051E – OCTOBER 1995 – REVISED APRIL 2019 Low Voltage Operation (continued) V+ 10.0V 6 REF102 R1 2 R2 4 Pt100 Cu K Cu RG Ref R3 100Ω = Pt100 at 0°C ISA TYPE E J K T MATERIAL µV/ + Chromel − Constantan + Iron − Constantan + Chromel − Alumel + Copper − Constantan VO INA128 SEEBECK COEFFICIENT ( C) R1, R2 58.5 66.5kΩ 50.2 76.8kΩ 39.4 97.6kΩ 38.0 102kΩ Figure 33. Thermocouple Amplifier With RTD Cold-Junction Compensation − VIN IO R1 RG INA128 V IN R1 G + Ref IB A1 A1 IB ERROR OPA177 ± 1.5nA OPA131 ± 50pA OPA602 ± 1pA OPA128 ± 75fA IO Load Figure 34. Differential Voltage to Current Converter Submit Documentation Feedback Copyright © 1995–2019, Texas Instruments Incorporated Product Folder Links: INA128 INA129 19 A newer version of this device is now available: INA828 INA128, INA129 SBOS051E – OCTOBER 1995 – REVISED APRIL 2019 www.ti.com Low Voltage Operation (continued) RG = 5.6kΩ 2.8kΩ G = 10 LA RA RG/2 VO INA128 Ref 2.8kΩ 390kΩ 1/2 OPA2131 RL VG VG 1/2 OPA2131 10kΩ 390kΩ 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 35. ECG Amplifier With Right-Leg Drive 11 Layout 11.1 Layout Guidelines Place the power-supply bypass capacitor as closely as possible to the supply and ground pins. The recommended value of this bypass capacitor is 0.1 μF to 1 μF. If necessary, additional decoupling capacitance can be added 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 part. 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 36. Recommended Layout 20 Submit Documentation Feedback Copyright © 1995–2019, Texas Instruments Incorporated Product Folder Links: INA128 INA129 A newer version of this device is now available: INA828 INA128, INA129 www.ti.com SBOS051E – OCTOBER 1995 – REVISED APRIL 2019 12 Device and Documentation Support 12.1 Related Links Table 1 lists quick access links. Categories include technical documents, support and community resources, tools and software, and quick access to sample or buy. Table 1. Related Links PARTS PRODUCT FOLDER SAMPLE & BUY TECHNICAL DOCUMENTS TOOLS & SOFTWARE SUPPORT & COMMUNITY INA128 Click here Click here Click here Click here Click here INA129 Click here Click here Click here Click here Click here 12.2 Receiving Notification of Documentation Updates To receive notification of documentation updates, navigate to the device product folder on ti.com. In the upper right corner, click on Alert me 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. 12.3 Community Resources The following links connect to TI community resources. Linked contents are 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. TI E2E™ Online Community TI's Engineer-to-Engineer (E2E) Community. Created to foster collaboration among engineers. At e2e.ti.com, you can ask questions, share knowledge, explore ideas and help solve problems with fellow engineers. Design Support TI's Design Support Quickly find helpful E2E forums along with design support tools and contact information for technical support. 12.4 Trademarks E2E is a trademark of Texas Instruments. All other trademarks are the property of their respective owners. 12.5 Electrostatic Discharge Caution These devices have limited built-in ESD protection. The leads should be shorted together or the device placed in conductive foam during storage or handling to prevent electrostatic damage to the MOS gates. 12.6 Glossary SLYZ022 — 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 Documentation Feedback Copyright © 1995–2019, Texas Instruments Incorporated Product Folder Links: INA128 INA129 21 PACKAGE OPTION ADDENDUM www.ti.com 6-Feb-2020 PACKAGING INFORMATION Orderable Device Status (1) Package Type Package Pins Package Drawing Qty Eco Plan Lead/Ball Finish MSL Peak Temp (2) (6) (3) Op Temp (°C) Device Marking (4/5) INA128P ACTIVE PDIP P 8 50 Green (RoHS & no Sb/Br) NIPDAU N / A for Pkg Type INA128P INA128PA ACTIVE PDIP P 8 50 Green (RoHS & no Sb/Br) NIPDAU N / A for Pkg Type INA128P A INA128PG4 ACTIVE PDIP P 8 50 Green (RoHS & no Sb/Br) NIPDAU N / A for Pkg Type INA128P INA128U ACTIVE SOIC D 8 75 Green (RoHS & no Sb/Br) NIPDAU Level-3-260C-168 HR INA 128U INA128U/2K5 ACTIVE SOIC D 8 2500 Green (RoHS & no Sb/Br) NIPDAU Level-3-260C-168 HR INA 128U INA128U/2K5G4 ACTIVE SOIC D 8 2500 Green (RoHS & no Sb/Br) NIPDAU Level-3-260C-168 HR INA 128U INA128UA ACTIVE SOIC D 8 75 Green (RoHS & no Sb/Br) NIPDAU Level-3-260C-168 HR -40 to 125 INA 128U A INA128UA/2K5 ACTIVE SOIC D 8 2500 Green (RoHS & no Sb/Br) NIPDAU Level-3-260C-168 HR -40 to 125 INA 128U A INA128UA/2K5E4 ACTIVE SOIC D 8 2500 Green (RoHS & no Sb/Br) NIPDAU Level-3-260C-168 HR -40 to 125 INA 128U A INA128UA/2K5G4 ACTIVE SOIC D 8 2500 Green (RoHS & no Sb/Br) NIPDAU Level-3-260C-168 HR -40 to 125 INA 128U A INA128UAE4 ACTIVE SOIC D 8 75 Green (RoHS & no Sb/Br) NIPDAU Level-3-260C-168 HR -40 to 125 INA 128U A INA128UAG4 ACTIVE SOIC D 8 75 Green (RoHS & no Sb/Br) NIPDAU Level-3-260C-168 HR -40 to 125 INA 128U A INA128UG4 ACTIVE SOIC D 8 75 Green (RoHS & no Sb/Br) NIPDAU Level-3-260C-168 HR INA129P ACTIVE PDIP P 8 50 Green (RoHS & no Sb/Br) NIPDAU N / A for Pkg Type Addendum-Page 1 INA 128U INA129P Samples PACKAGE OPTION ADDENDUM www.ti.com 6-Feb-2020 Orderable Device Status (1) Package Type Package Pins Package Drawing Qty Eco Plan Lead/Ball Finish MSL Peak Temp (2) (6) (3) Op Temp (°C) Device Marking (4/5) INA129PA ACTIVE PDIP P 8 50 Green (RoHS & no Sb/Br) NIPDAU N / A for Pkg Type INA129P A INA129PG4 ACTIVE PDIP P 8 50 Green (RoHS & no Sb/Br) NIPDAU N / A for Pkg Type INA129P INA129U ACTIVE SOIC D 8 75 Green (RoHS & no Sb/Br) NIPDAU Level-3-260C-168 HR INA 129U INA129U/2K5 ACTIVE SOIC D 8 2500 Green (RoHS & no Sb/Br) NIPDAU Level-3-260C-168 HR INA 129U INA129UA ACTIVE SOIC D 8 75 Green (RoHS & no Sb/Br) NIPDAU Level-3-260C-168 HR -40 to 125 INA 129U A INA129UA/2K5 ACTIVE SOIC D 8 2500 Green (RoHS & no Sb/Br) NIPDAU Level-3-260C-168 HR -40 to 125 INA 129U A INA129UA/2K5G4 ACTIVE SOIC D 8 2500 Green (RoHS & no Sb/Br) NIPDAU Level-3-260C-168 HR -40 to 125 INA 129U A INA129UAE4 ACTIVE SOIC D 8 75 Green (RoHS & no Sb/Br) 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