Texas Instruments INA146UA

Overview

INA146UA from Texas Instruments is a high-voltage, programmable-gain difference amplifier designed for precision measurement of differential signals in the presence of extreme common-mode voltages - up to ±100V at ±15V supplies. It delivers 0.1V/V to 100V/V gain via external resistors, features 80dB CMRR, 0.025% gain error, and operates from single (4.5–36V) or dual (±2.25–±18V) supplies. It is used in battery cell formation equipment to isolate and scale high-voltage stack measurements while preserving signal integrity.

For engineers reviewing the INA146UA datasheet, INA146UA pinout, INA146UA application, or INA146UA equivalent, key selection considerations include its rail-to-rail input common-mode range beyond supply rails, laser-trimmed internal resistor network enabling stable gain accuracy over temperature, low 570µA quiescent current for power-sensitive systems, and SOIC-8 packaging qualified for –40°C to 85°C industrial operation.

Technical Context

The INA146UA integrates two precision amplifiers (A1 and A2) with a fixed 10:1 input attenuator stage followed by a programmable-gain output buffer. Its input stage uses laser-trimmed thin-film resistors to achieve 80dB CMRR and <0.025% gain error, with TCR-matched elements ensuring stability across –40°C to 85°C. The Ref pin (pin 1) allows offset adjustment and sets the common-mode reference point for the internal A1 non-inverting input node.

Gain is set externally using RG1 and RG2 per G = 0.1 × (1 + RG2/RG1), maintaining full common-mode input range regardless of gain setting. The VO1 pin provides access to A1's output, enabling use as a precision current source or filter interface, while VO delivers the final amplified difference signal.

Key Specifications

Pinout & Package

The INA146UA is housed in an industry-standard SOIC-8 surface-mount package (4.90mm × 6.00mm), specified for operation from –40°C to 85°C and compatible with standard reflow profiles.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar high-voltage difference amplifier applications.

Compared with INA148UA and AD8479ARZ, the INA146UA uniquely balances programmable gain, ultra-low quiescent current, and dual-output capability - making it optimal for cost-constrained, thermally sensitive industrial systems requiring field-configurable scaling without sacrificing precision or rail-to-rail input operation.

Availability

INA146UA is available at Aetrix Electronics and suitable for battery test systems, industrial motor controls, HVAC energy meters, and programmable power supplies requiring stable component supply across extended temperature and long production lifecycles.

Supply support for INA146UA 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 delivering analog and embedded processing solutions for industrial, automotive, and communications markets.

The INA146UA belongs to TI's precision difference amplifier product line, engineered specifically for high-voltage signal conditioning in harsh electrical environments - emphasizing rail-to-rail common-mode operation, laser-trimmed accuracy, and robust thermal performance from –40°C to 85°C.

FAQ

What is the maximum common-mode voltage the INA146UA can handle?

The INA146UA supports up to ±100V common-mode input voltage when operated with ±15V supplies, and up to 40V with a 5V single supply. This capability is enabled by its internal 10:1 resistor ratio and rail-to-rail input stage design, allowing direct measurement of high-voltage battery cells or motor phases without external attenuation. The exact limit depends on supply voltage and Ref pin configuration as defined in the datasheet's common-mode range equations.

How is gain programmed on the INA146UA?

Gain on the INA146UA is programmed using two external resistors (RG1 and RG2) connected between pins 1 (Ref) and 5 (RG), following the formula G = 0.1 × (1 + RG2/RG1). Standard 1% resistor values are provided in the datasheet for gains from 0.1V/V to 100V/V. The internal 10kΩ resistor at VO1 ensures bias current cancellation, preserving the specified 0.025% gain error across all configurations.

Does the INA146UA require external compensation or filtering?

The INA146UA is internally compensated and stable with capacitive loads up to 1nF. However, for noise-sensitive applications like precision DAQ, a 1500pF capacitor across RG2 (as shown in Figure 6-4 of the datasheet) adds a 106Hz pole to suppress high-frequency interference. No external compensation is needed for basic operation, but RC filtering at VO or VO1 is recommended when driving ADCs or long cables to prevent aliasing or ringing.

What is the function of the VO1 pin on the INA146UA?

The VO1 pin on the INA146UA provides access to the output of the first-stage amplifier (A1), which delivers the 0.1× attenuated difference signal before the programmable-gain buffer (A2). This enables use cases such as precision current sourcing (Figure 6-10), active filtering, or feeding a secondary signal path - all while preserving the main VO output for primary system feedback. VO1 has a 10kΩ internal series resistor trimmed to ±1% for consistent performance.

Is the INA146UA suitable for single-supply operation?

Yes, the INA146UA is fully specified for single-supply operation from 4.5V to 36V. Its input common-mode range extends beyond both supply rails, and the Ref pin (pin 1) allows setting the output mid-point - for example, tying Ref to VS/2 enables rail-to-rail output swing referenced to half-supply. Key parameters including gain error, CMRR, and bandwidth are guaranteed across the full –40°C to 85°C temperature range under single-supply conditions.