Texas Instruments INA114AU

Overview

INA114AU from Texas Instruments is a precision instrumentation amplifier with laser-trimmed 50 µV max offset voltage, 0.3 µV/°C max drift, and 115 dB min CMRR at G = 1000 - designed for high-accuracy signal conditioning in industrial sensor interfaces and medical instrumentation.

For engineers reviewing the INA114AU datasheet, INA114AU pinout, INA114AU application, or INA114AU equivalent, key selection considerations include gain-setting resistor dependency (G = 1 + 50 kΩ/R_G), ±40 V input overvoltage protection, SOIC-16 package thermal resistance (74.2 °C/W), and chip-site-origin-dependent bandwidth (1 MHz at G = 1 for CSO:SHE).

Technical Context

The INA114AU implements a three-op-amp topology with internal laser-trimmed thin-film feedback resistors enabling precise gain control via a single external resistor. Its input stage features FET-based amplifiers delivering 100 GΩ || 6 pF common-mode and differential impedance.

It supports dual-supply operation from ±2.25 V to ±18 V and single-supply operation from +4.5 V to +36 V, with output swing limited to (V^–) + 1.5 V to (V⁺) – 1.5 V at full temperature range (–40°C to +85°C) and load current ≤5 mA.

Key Specifications

Pinout & Package

INA114AU is supplied in a 16-pin SOIC (DW) surface-mount package measuring 10.3 mm × 10.3 mm, with 74.2 °C/W junction-to-ambient thermal resistance. Pin functions are validated per TI SBOS014B Figure 4-1 (SOIC top view).

Key Features

Applications

Equivalent & Alternatives

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

Compared with INA128UA and AD620ARZ, the INA114AU trades marginal offset/CMRR performance for superior input ruggedness and simpler gain-setting - making it optimal for cost-sensitive, high-reliability industrial and transportation applications where ±40 V fault tolerance is non-negotiable.

Availability

INA114AU is available at Aetrix Electronics and suitable for RTD temperature measurement, ECG signal conditioning, bridge transducer interface, and train control signal amplification requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for INA114AU 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 leader specializing in analog and embedded processing technologies, with decades of heritage in precision signal chain components.

The INA114AU belongs to TI's precision instrumentation amplifier product line, engineered specifically for high-accuracy, low-drift industrial and medical sensor signal conditioning where reliability under electrical stress and thermal variation is critical.

FAQ

What is the maximum gain achievable with the INA114AU, and how is it set?

The INA114AU supports a gain range of 1 to 10,000 V/V, set by a single external resistor RG using the equation G = 1 + 50 kΩ/R_G. For G = 10,000, RG = 5 Ω - requiring careful PCB layout to minimize parasitic resistance. The INA114AU's internal laser-trimmed 50 kΩ feedback network ensures stable gain accuracy across temperature, with typical gain error ≤±0.5% at G = 1000.

Does the INA114AU require external input protection when interfacing with industrial sensors?

No - the INA114AU includes integrated input protection that withstands ±40 V applied to either input terminal, even with no power applied. This eliminates the need for external TVS diodes or series resistors in applications like trackside signaling or multifunction relay monitoring, where transient overvoltages are common. The protection circuit limits input current to ~1.5 mA during overload.

How does the SOIC-16 package of the INA114AU differ functionally from the PDIP-8 version?

The INA114AU SOIC-16 adds two dedicated pins (Pin 11: OUT SENSE; Pin 12: SENSE) for remote Kelvin output sensing - enabling accurate load regulation in long-cable or high-current applications. These pins are internally shorted in the PDIP-8 variant. Additionally, the SOIC-16 offers lower thermal resistance (74.2 °C/W vs 110.2 °C/W), improving power dissipation capability in compact industrial modules.

What is the input bias current specification for the INA114AU, and why does it matter in high-impedance sensor circuits?

The INA114AU has a maximum input bias current of ±5 nA at 25°C, with ±8 pA/°C drift over –40°C to +85°C. In high-impedance applications like thermocouple or pH probe interfaces, this bias current flows through source resistance, creating offset voltage errors. For example, a 1 MΩ source generates up to 5 mV of error - necessitating balanced return paths (e.g., matched 1 MΩ resistors to REF) to cancel common-mode effects and preserve CMRR.

Can the INA114AU operate from a single 5-V supply, and what are the output swing limitations?

Yes - the INA114AU operates from a single +4.5 V to +36 V supply. With a +5 V supply and REF tied to 2.5 V, the output swings from ~1.0 V to ~4.0 V (i.e., ≥1.5 V headroom from each rail) at 5 mA load and full temperature range. This allows direct interfacing with 5 V ADCs or microcontrollers without level-shifting, provided the REF pin is stabilized with a low-noise voltage reference or buffered divider.