Texas Instruments INA114BU

Overview

INA114BU from Texas Instruments is a precision instrumentation amplifier designed for high-accuracy signal conditioning in low-noise, high-common-mode-noise environments. It delivers 50µV max offset voltage, 0.3µV/°C max drift, 115dB min CMRR at G=1000, ±2.25V to ±18V dual-supply operation, and input over-voltage protection up to ±40V - enabling reliable use in surgical equipment and train control systems.

For engineers reviewing the INA114BU datasheet, INA114BU pinout, INA114BU application, or INA114BU equivalent, key selection criteria include guaranteed low-drift performance across –40°C to +85°C, single-resistor programmable gain (1–10,000), internal laser-trimmed resistors, SOIC-16 package compatibility, and input protection that remains functional with no supply applied.

Technical Context

The INA114BU implements a three-op-amp architecture with fully differential inputs and output referenced to the REF pin. Its gain is set by a single external resistor (RG) using G = 1 + 50kΩ/RG, where the 50kΩ term derives from on-chip laser-trimmed metal-film resistors ensuring stable temperature coefficient and absolute accuracy.

Input stage bias current is limited to ±2nA max with ±40V fault tolerance per input, and internal protection circuitry clamps input current to ~1.5mA during overload - independent of power supply presence. The device supports both single-supply (4.5V to 36V) and dual-supply (±2.25V to ±18V) operation, with output swing specified as (V–)+1.5V to (V+)-1.5V at full temperature range.

Key Specifications

Pinout & Package

The INA114BU is supplied in a 16-pin SOIC (DW) surface-mount package measuring 10.3mm × 10.3mm, rated for –40°C to +85°C operation.

Key Features

Applications

Equivalent & Alternatives

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

Compared with INA128UA and AD620ARZ, the INA114BU uniquely balances rugged input protection, laser-trimmed DC accuracy, and SOIC-16 compatibility - making it optimal for cost-sensitive industrial control designs where field reliability and calibration longevity are prioritized over ultra-low power or ultra-high speed.

Availability

INA114BU is available at Aetrix Electronics and suitable for surgical equipment, train control and management, multifunction relay, and actuator applications requiring stable component supply across extended product lifecycles.

Supply support for INA114BU 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 specializing in analog and embedded processing technologies, with leadership in precision analog ICs since 1951.

The INA114BU belongs to TI's precision instrumentation amplifier product line, engineered specifically for high-accuracy DC-coupled measurement in industrial, medical, and transportation systems where long-term stability and fault resilience are critical.

FAQ

What is the maximum gain achievable with the INA114BU, and how is it set?

The INA114BU supports gains from 1 to 10,000, set by a single external resistor RG connected between Pins 1 and 8 (or Pin 1 to ground for G > 1). The gain equation is G = 1 + 50kΩ/RG. For G = 10,000, RG = 5Ω; for G = 1, RG is open. The 50kΩ term is laser-trimmed on-die, ensuring accuracy and low temperature drift. The INA114BU datasheet specifies gain error as low as ±0.02% at G = 10 and ±1% at G = 1000.

Does the INA114BU require external components for basic operation?

Yes - the INA114BU requires at minimum an external gain-setting resistor (RG) between Pin 1 and Pin 8 (or ground), plus local 0.1µF ceramic decoupling capacitors on V+ (Pin 7) and V– (Pin 4). The REF pin (Pin 5) must be connected to a low-impedance reference (typically ground or DAC output) - impedance ≤5Ω is mandatory to preserve CMRR. No external trimming or compensation is needed for standard operation, as the INA114BU is laser-trimmed for offset and drift.

Can the INA114BU operate from a single 5V supply?

Yes, the INA114BU supports single-supply operation from 4.5V to 36V. At 5V, the output swing is specified as 1V to 4V (V– +1V to V+ –1V) over temperature, and input common-mode range extends from 1V to 4V. To ensure linear operation, the REF pin should be biased to mid-supply (e.g., 2.5V) using a low-impedance source. The INA114BU's ability to operate down to ±2.25V dual supply or 4.5V single supply makes it compatible with modern low-voltage embedded systems.

What is the purpose of Pins 12 (OS–) and 13 (OS+) on the INA114BU SOIC package?

Pins 12 (OS–) and 13 (OS+) are optional offset trim terminals on the INA114BU SOIC-16 package, allowing fine adjustment of output offset voltage via an external potentiometer or DAC. They are not required for standard operation - the INA114BU is laser-trimmed to 50µV max offset and typically needs no external trimming. When used, OS– and OS+ form a differential input to the internal offset correction circuit; connecting them as shown in Figure 6-2 of the INA114BU datasheet enables ±10mV of adjustable offset range.

How does the INA114BU handle input overvoltage conditions, and is protection active without power applied?

The INA114BU provides ±40V continuous input overvoltage protection on both IN+ and IN– pins, with internal current limiting (~1.5mA) that remains fully functional even when no power supply is connected. This protection operates independently of V+ and V– rails, preventing damage from field-wiring faults, ESD events, or accidental connection to higher-voltage sources. Unlike many amplifiers, the INA114BU's input protection does not rely on supply-rail clamping diodes - it uses dedicated on-chip circuitry that protects the inputs under all conditions, including unpowered states.