Texas Instruments INA131BPG4

Overview

INA131BPG4 from Texas Instruments (originally Burr-Brown) is a precision instrumentation amplifier with fixed G = 100 gain, designed for low-drift, high-CMR signal conditioning in sensor front-ends. It features ±50 µV max input offset voltage, 110 dB min CMR at ±10 V common-mode, ±40 V input overvoltage protection, and operates from ±2.25 V to ±18 V supplies - ideal for thermocouple, RTD, and bridge amplifier applications requiring stable DC accuracy.

For engineers reviewing the INA131BPG4 datasheet, INA131BPG4 pinout, INA131BPG4 application, or INA131BPG4 equivalent, this page delivers verified specifications, validated DIP-8 pin mapping, real-world use cases in medical and industrial sensing, and two confirmed alternative parts with documented functional trade-offs.

Technical Context

The INA131BPG4 uses a 3-op-amp architecture with on-chip laser-trimmed thin-film resistors to fix gain at 100 with ±0.024% typical error and ±5 ppm/°C drift. Its input stage includes integrated ±40 V fault protection diodes and achieves 10¹⁰ Ω || 6 pF input impedance, enabling direct connection to high-impedance sensors without external protection.

Common-mode rejection is maintained above 106 dB across –40°C to +85°C via matched internal resistor ratios and low-offset A1/A2 amplifiers. The output stage provides ±13.5 V swing into 2 kΩ at ±15 V supply, with 70 kHz bandwidth and 0.7 V/µs typical slew rate - optimized for DC-critical, low-frequency measurement systems.

Key Specifications

Pinout & Package

INA131BPG4 is housed in an 8-pin plastic DIP (PDIP-P) package with 0.3-inch body width and through-hole mounting. Pin spacing is 0.1 inch, compatible with standard prototyping and production PCB layouts.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar instrumentation amplifier applications.

Compared with INA131BPG4, INA126PA offers higher gain but sacrifices CMR and input ruggedness, while AD620ANZ improves speed and noise but removes integrated overvoltage protection - making INA131BPG4 uniquely suited for cost-sensitive, field-deployed sensor nodes demanding robustness and DC precision.

Availability

INA131BPG4 is available at Aetrix Electronics and suitable for bridge amplifier, thermocouple amplifier, and RTD sensor amplifier applications requiring stable component supply, long-term calibration retention, and industrial-grade reliability.

Supply support for INA131BPG4 includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Texas Instruments acquired Burr-Brown in 2000 and maintains its precision analog portfolio, including instrumentation amplifiers, voltage references, and data converters - with global manufacturing and qualification per AEC-Q200 and ISO 9001 standards.

The INA131BPG4 belongs to TI's legacy precision instrumentation amplifier family, engineered specifically for DC-critical industrial and medical sensor signal chains where gain stability, low drift, and input fault tolerance are non-negotiable.

FAQ

What is the maximum input common-mode voltage range for INA131BPG4?

The INA131BPG4 supports an input common-mode voltage range of ±13.5 V at ±15 V supply, limited by the output swing of its internal A1 and A2 amplifiers. This range decreases linearly with lower supply voltages - e.g., ±10 V at ±11.4 V supply and ±1 V at ±2.25 V supply. The device maintains functionality up to ±40 V inputs due to internal overvoltage protection, though linear operation ceases beyond the specified common-mode range. Always reference the "Input Common-Mode Range vs Output Voltage" curve in the INA131BPG4 datasheet for design margining.

Can INA131BPG4 operate from a single supply?

Yes, INA131BPG4 can operate from a single supply by biasing the Ref pin to mid-rail (e.g., VCC/2) and ensuring both inputs remain within the valid common-mode window relative to that reference. For example, with +15 V and GND supplies, tie Ref to +7.5 V via a low-impedance source, and keep IN+ and IN– between +1.25 V and +13.75 V. The output will swing around +7.5 V. Note that quiescent current remains ±3 mA, and input protection still functions up to ±40 V relative to GND - critical for single-supply systems interfacing with bipolar sensors.

Does INA131BPG4 require external resistors to achieve G = 100?

No, INA131BPG4 does not require external resistors to achieve G = 100. Its gain is set by on-chip laser-trimmed thin-film resistors, delivering ±0.024% typical gain error and ±5 ppm/°C drift without any external components. Pins 1 and 8 (RG) are provided only for optional gain increase beyond 100 using an external resistor; they are left unconnected in standard G = 100 configurations. This eliminates resistor matching errors and board space, simplifying layout and improving long-term stability versus discrete resistor-based designs.

How does the input overvoltage protection in INA131BPG4 work?

INA131BPG4 incorporates internal series protection diodes on both IN+ and IN– inputs, clamping to the supply rails and limiting input current to ~1.5 mA during overvoltage events. This allows safe operation with inputs up to ±40 V even when no power is applied - protecting downstream circuitry from wiring faults, relay kickback, or ESD. Unlike external diode solutions, this integrated protection adds no series resistance or leakage current under normal conditions, preserving the device's 10¹⁰ Ω input impedance and ±2 nA bias current spec. The protection is fully characterized across temperature and does not degrade CMR or offset performance.

What is the typical settling time of INA131BPG4 for a 0.01% step response?

The INA131BPG4 has a typical settling time of 100 µs to 0.01% for a full-scale step input at G = 100, as measured under standard conditions (TA = +25°C, VS = ±15 V, RL = 2 kΩ). This value holds across the full operating temperature range (–40°C to +85°C) with minimal variation. Settling is dominated by the 70 kHz small-signal bandwidth and 0.7 V/µs slew rate; for larger output swings (>±10 V), overload recovery adds ~20 µs. This makes INA131BPG4 suitable for multiplexed data acquisition systems with channel switching rates up to 10 kHz, provided adequate acquisition delay is allowed.