Texas Instruments OPA627AUE4

Overview

OPA627AUE4 from Texas Instruments is a precision JFET-input operational amplifier designed for high-speed, low-noise analog signal conditioning in demanding measurement and acquisition systems. It delivers 4.5 nV/√Hz input voltage noise at 10 kHz, 150 V/μs slew rate, 45 MHz gain-bandwidth product, and ±125 μV maximum input offset voltage - enabling accurate amplification of weak sensor signals in DAC output stages and ultrasound front-ends.

For engineers reviewing the OPA627AUE4 datasheet, OPA627AUE4 pinout, OPA627AUE4 application, or OPA627AUE4 equivalent, key selection criteria include unity-gain stability, ultra-low input bias current (±5 pA max), wide supply range (±4.5 V to ±18 V), thermal performance in SOIC-8 packaging, and compatibility with high-impedance source topologies requiring minimal loading error.

Technical Context

The OPA627AUE4 employs dielectrically isolated complementary NPN/PNP FET transistors to achieve simultaneous low input bias current and low voltage noise - a trade-off historically difficult in precision op amps. Its laser-trimmed input stage ensures ±125 μV VOS and ±1.3 μV/°C drift over –25°C to +85°C, supporting stable DC-coupled instrumentation without frequent recalibration.

Unlike the higher-bandwidth OPA637, the OPA627AUE4 is unity-gain stable and optimized for configurations where noise gain ≤ 1 (e.g., buffers, integrators, active filters). Its open-loop gain exceeds 130 dB and CMRR reaches 110 dB, ensuring high common-mode rejection in differential sensing applications with asymmetric PCB layouts.

Key Specifications

Pinout & Package

OPA627AUE4 is packaged in an 8-pin SOIC (D package) with exposed pad thermal enhancement. Pin 1, 5, and 8 are no-connect terminals; pins 2 and 3 serve as inverting and noninverting inputs; pin 4 is negative supply (V–); pin 6 is output; pin 7 is positive supply (V+).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar precision JFET op amp applications.

Compared with OPA627BM, the OPA627AUE4 trades extended temperature capability and tighter offset specs for lower unit cost and standard industrial qualification. Against OPA140AIDBVR, it delivers 2.25× higher slew rate and 2.25× greater bandwidth - making it preferable for time-critical acquisition and wideband active filtering.

Availability

OPA627AUE4 is available at Aetrix Electronics and suitable for precision instrumentation, fast data acquisition, and DAC output amplification requiring stable component supply across industrial, test & measurement, and medical device programs.

Supply support for OPA627AUE4 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 high-performance op amp design and manufacturing.

The OPA627AUE4 belongs to TI's OPA6x7 precision JFET op amp family, engineered specifically for applications demanding simultaneous low noise, low drift, high speed, and unity-gain stability - such as ultrasound receivers, optical sensor interfaces, and metrology-grade signal chains.

FAQ

What is the maximum recommended supply voltage for OPA627AUE4?

The OPA627AUE4 supports dual-supply operation from ±4.5 V to ±18 V, with absolute maximum ratings of ±18 V. Operating beyond ±18 V risks permanent damage. For optimal noise and distortion performance, TI recommends ±15 V supplies - matching the conditions under which key specs like 4.5 nV/√Hz noise and 150 V/μs slew rate were characterized in the OPA627AUE4 datasheet.

Is OPA627AUE4 unity-gain stable, and what does that mean for circuit design?

Yes, the OPA627AUE4 is explicitly unity-gain stable per its datasheet. This means it remains stable without oscillation when configured as a voltage follower (gain = 1) or in any closed-loop configuration with noise gain ≤ 1 - including integrators, transimpedance amplifiers, and active filters. Designers can implement these topologies without adding phase-compensation components, simplifying layout and improving repeatability in production.

How does OPA627AUE4 compare to OPA637 in terms of stability and bandwidth?

The OPA627AUE4 is unity-gain stable with 45 MHz GBW, while the OPA637 requires minimum noise gain ≥ 5 and achieves 80 MHz GBW. The OPA627AUE4 is preferred for low-gain, wideband applications like buffers and integrators; the OPA637 suits higher-gain, higher-speed circuits (e.g., noninverting amps with G ≥ 5). Using OPA637 in unity-gain risks instability unless carefully compensated - a risk avoided entirely with OPA627AUE4.

What is the input bias current specification for OPA627AUE4, and why does it matter?

The OPA627AUE4 has a maximum input bias current of ±5 pA at 25°C, with typical values near ±0.2 pA. This ultra-low IB is critical when interfacing with high-impedance sources (e.g., pH electrodes, photodiodes, or piezoelectric sensors), where even nanoampere-level currents cause significant voltage errors across feedback or source impedances. It ensures minimal loading-induced offset and preserves signal fidelity in precision measurement paths.

Can OPA627AUE4 drive capacitive loads, and what is the recommended layout practice?

Yes, the OPA627AUE4 is characterized for stability with ≥30 pF capacitive loads when properly decoupled. Layout best practices include placing 0.1 μF ceramic decoupling capacitors within 5 mm of pins 4 (V–) and 7 (V+), using short, low-inductance traces to the output, and avoiding long unterminated traces to the inverting input. For loads >100 pF, consider adding a small series resistor (10–50 Ω) between output and capacitance to isolate reactive feedback.