Texas Instruments INA851RGTT

Overview

INA851RGTT from Texas Instruments is a precision, low-noise instrumentation amplifier with fully differential outputs, integrated output clamping, and programmable gain from 0.2 to 10,000 via external resistor. It delivers 10 µV typical input offset voltage, 3.2 nV/√Hz input voltage noise, 22 MHz bandwidth at G = 0.2, and operates from ±4 V to ±18 V dual supply or 8 V to 36 V single supply - optimized for driving high-performance ADCs in medical ECG and industrial weigh-scale systems.

For engineers reviewing the INA851RGTT datasheet, INA851RGTT pinout, INA851RGTT application, or INA851RGTT equivalent, key selection considerations include its differential output stage with VOCM control, ±40 V input overvoltage protection, 0.2/1 selectable output-stage gain, and VQFN-16 package thermal performance (RθJB = 22.1 °C/W).

Technical Context

The INA851RGTT implements a three-op-amp architecture with super-beta input transistors enabling ultra-low input bias current (5 nA typ) and low current noise (0.8 pA/√Hz). Its output stage is a fully differential amplifier (FDA) with independent VOCM control and built-in clamping circuitry referenced to externally set VCLAMP+ and VCLAMP– pins.

Gain is split into two stages: input-stage gain GIN = 1 + 6 kΩ/RG (set by external resistor between pins 2 and 3), and output-stage gain GOUT = 0.2 or 1 (selected by shorting G02–/G02+ to OUT–/OUT+, respectively). Total gain is G = GIN × GOUT, supporting precise signal conditioning across wide dynamic ranges without external FDA components.

Key Specifications

Pinout & Package

The INA851RGTT is housed in a 16-pin VQFN package (RGT) with 3.00 mm × 3.00 mm body size and exposed thermal pad requiring PCB connection to VS– or ground plane for thermal management.

Key Features

Applications

Equivalent & Alternatives

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

Compared with INA818IDRCT and INA849IDRCT, the INA851RGTT uniquely integrates differential output drive, configurable clamping, and VOCM control - reducing component count and layout risk in ADC-coupled systems, while maintaining competitive offset and drift specs.

Availability

INA851RGTT is available at Aetrix Electronics and suitable for analog input modules, flow transmitters, and electrocardiogram (ECG) systems requiring stable component supply, long-term manufacturability, and guaranteed traceability.

Supply support for INA851RGTT 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 is a global semiconductor company delivering analog and embedded processing solutions for industrial, automotive, and personal electronics markets.

The INA851RGTT belongs to TI's precision instrumentation amplifier product line, designed specifically to replace discrete FDA-based ADC driver circuits with integrated, robust, and layout-efficient signal conditioning for high-resolution data acquisition.

FAQ

What is the maximum gain achievable with the INA851RGTT?

The INA851RGTT supports total gain from G = 0.2 to 10,000. This is achieved by combining input-stage gain GIN = 1 + 6 kΩ/RG (set by external resistor RG) with output-stage gain GOUT = 0.2 or 1. For example, with RG = 0.6 Ω, GIN = 10,001 and GOUT = 0.2 yields G = 2000.2; with RG open, GIN = 1 and GOUT = 1 gives G = 1. The INA851RGTT datasheet specifies G = 0.2 to 10,000 as the operational range.

How does the output clamping function work on the INA851RGTT?

The INA851RGTT uses dedicated VCLAMP+ and VCLAMP– pins to define clamping thresholds. When VCLAMP+ is set to VS+ – 1.5 V and VCLAMP– to VS– + 1.5 V, the outputs clamp within a ±3 V window centered on VOCM. Clamping activates only when outputs exceed these limits, protecting downstream ADCs. If clamping is unused, connect VCLAMP+ to VS+ and VCLAMP– to VS–. The INA851RGTT's internal clamping circuitry responds without external components.

Can the INA851RGTT operate from a single 12-V supply?

Yes, the INA851RGTT supports single-supply operation from 8 V to 36 V. With VS+ = 12 V and VS– = GND, it meets all recommended operating conditions. Input common-mode range extends from (VS–) + 2.5 V to (VS+) – 2.5 V (i.e., 2.5 V to 9.5 V), and output swing reaches (VS–) + 1.4 V to (VS+) – 1.4 V (1.4 V to 10.6 V). VOCM can be set to 6 V for midsupply operation. The INA851RGTT maintains specified performance across this range.

What is the purpose of the G02+ and G02– pins on the INA851RGTT?

G02+ (pin 12) and G02– (pin 9) configure the output-stage gain GOUT. Shorting G02– to OUT– and G02+ to OUT+ sets GOUT = 0.2 V/V; leaving both pins floating sets GOUT = 1 V/V. This allows flexible scaling: GOUT = 0.2 preserves full ADC input range when using high GIN values (e.g., GIN = 1000), while GOUT = 1 maximizes signal-to-noise ratio at lower gains. The INA851RGTT's dual-gain architecture decouples input and output optimization.

Does the INA851RGTT require external compensation capacitors?

No, the INA851RGTT is internally compensated and stable for differential loads up to 100 pF without external compensation. Its closed-loop output impedance is 0.9 Ω at 1 MHz, and it drives standard 10-kΩ ADC input impedances directly. Layout best practices (short traces, ground plane under thermal pad, proper decoupling) are sufficient. The INA851RGTT datasheet confirms stability across gain settings and load conditions without added capacitors.