Texas Instruments INA163UA/2K5

Overview

INA163UA/2K5 from Texas Instruments is a low-noise, low-distortion instrumentation amplifier optimized for professional audio signal conditioning. It delivers 1nV/√Hz input voltage noise at 1kHz, 0.002% THD+N at G=100, and 800kHz bandwidth at G=100, operating from ±4.5V to ±18V supplies. Its primary role is differential amplification of low-level balanced microphone and transducer signals in high-fidelity preamplifier stages.

For engineers reviewing the INA163UA/2K5 datasheet, INA163UA/2K5 pinout, INA163UA/2K5 application, or INA163UA/2K5 equivalent, key selection criteria include input-referred noise performance at 200Ω source impedance, gain accuracy via external RG resistor, common-mode rejection >100dB at G=100, and SO-14 package thermal and layout compatibility for low-noise PCB design.

Technical Context

The INA163UA/2K5 employs current-feedback architecture with laser-trimmed 3kΩ internal feedback resistors, enabling wide bandwidth (800kHz at G=100) and fast settling (2µs to 0.1% for 10V step). Its distortion cancellation circuitry achieves 0.002% THD+N at 1kHz and G=100, critical for high-fidelity audio chain integrity.

It features differential inputs with 60MΩ || 2pF impedance, output sense (pin 8) and reference (pin 10) terminals for load-regulated gain accuracy, and rail-to-rail output swing within 1.8V of supply rails into 2kΩ. Input common-mode range extends to (V±) ±3V, supporting wide dynamic signal capture.

Key Specifications

Pinout & Package

INA163UA/2K5 is housed in a SOIC-14 (D) surface-mount package, 8.75mm × 3.91mm × 1.75mm, RoHS-compliant with NIPDAU lead finish and MSL Level-3 rating.

Key Features

Applications

Equivalent & Alternatives

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

Compared with INA163UA/2K5, INA165UA/2K5 improves noise by 0.15nV/√Hz at cost of +4mA supply current, while AD8221ARMZ trades Sense/Ref functionality and SO-14 layout compatibility for smaller MSOP-8 size - neither is pin-compatible, but both serve overlapping low-noise instrumentation roles.

Availability

INA163UA/2K5 is available at Aetrix Electronics and suitable for professional audio equipment, industrial transducer signal chains, precision test instrumentation, and medical sensor interfaces requiring stable component supply and long-term manufacturability.

Supply support for INA163UA/2K5 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, embedded processing, and connectivity technologies, with decades of expertise in precision signal chain solutions.

The INA163UA/2K5 belongs to TI's high-performance instrumentation amplifier product line, engineered specifically for low-noise, low-distortion audio and measurement applications demanding exceptional dynamic range and DC accuracy.

FAQ

What is the minimum external gain-setting resistor value for stable operation of the INA163UA/2K5?

The INA163UA/2K5 supports gain from 1 to 10000 using the equation G = 1 + 6000/RG. For G=10000, RG = 6000/9999 ≈ 0.6Ω - however, practical minimum is 10Ω to avoid excessive current and thermal drift. TI recommends RG ≥ 61Ω for G ≤ 1000, ensuring <±0.5% gain error and stable thermal behavior. The INA163UA/2K5 datasheet specifies RG values down to 6Ω (G=1001), but 61Ω is the lowest value validated for production use across temperature.

Does the INA163UA/2K5 support true rail-to-rail output swing?

No, the INA163UA/2K5 does not provide rail-to-rail output. Its output voltage swing is specified as (V+) − 1.8V to (V−) + 1.8V into a 2kΩ load. At ±15V supplies, this yields a usable output range of ±13.2V - a 1.8V headroom per rail. This limitation arises from its bipolar output stage architecture. The INA163UA/2K5 maintains excellent linearity within this range, but cannot drive signals within 1.8V of either supply rail.

Can the Sense and Ref pins of the INA163UA/2K5 be left unconnected in basic applications?

Yes - Sense (pin 8) and Ref (pin 10) may be left unconnected in standard configurations where output load regulation and DC offset trimming are not required. When unused, Sense should be tied to VO1 (pin 4), and Ref should be grounded or tied to VO1. Leaving them floating is not recommended. The INA163UA/2K5 functions fully as a conventional instrumentation amplifier without these pins, but their omission forfeits gain accuracy improvement and active offset control capabilities.

What is the maximum source impedance for optimal noise performance of the INA163UA/2K5?

The INA163UA/2K5 delivers near-theoretical noise performance only with source impedances ≤10kΩ, and is optimized for 200Ω. Its 1nV/√Hz voltage noise dominates at low ZS, but its 0.8pA/√Hz current noise becomes significant above 10kΩ, degrading total input-referred noise. For ZS > 10kΩ, total noise rises sharply - e.g., at 100kΩ, noise exceeds 10nV/√Hz. Thus, the INA163UA/2K5 is best applied with low-impedance transducers, not high-Z piezoelectric or FET-based sensors.

Is the INA163UA/2K5 qualified for automotive applications?

No, the INA163UA/2K5 is specified for industrial temperature range (–40°C to +85°C) and is not AEC-Q200 qualified. While it operates up to +125°C junction temperature, it lacks automotive-grade screening, extended reliability testing, and PPAP documentation. For automotive microphone preamps or cabin sensor interfaces, TI recommends the pin-compatible INA163-Q1 (AEC-Q100 Grade 2, –40°C to +105°C), which shares identical electrical specs but includes automotive qualification and enhanced ESD robustness.