Texas Instruments OPA627AUG4

Overview

OPA627AUG4 from Texas Instruments is a precision JFET-input operational amplifier optimized for high-speed, low-noise analog signal conditioning in demanding instrumentation and data acquisition systems. It delivers 4.5nV/√Hz input voltage noise at 10kHz, 150V/μs slew rate, and 45MHz gain-bandwidth product while remaining unity-gain stable - enabling accurate amplification of fast, low-level signals such as those from piezoelectric sensors or DAC outputs.

For engineers reviewing the OPA627AUG4 datasheet, OPA627AUG4 pinout, OPA627AUG4 application, or OPA627AUG4 equivalent, key selection criteria include its ultra-low input bias current (±5pA max), low offset drift (±0.8µV/°C max), wide ±4.5V to ±18V dual-supply operation, and SOIC-8 package compatibility with high-impedance, low-distortion signal chains requiring <0.00003% THD+N.

Technical Context

The OPA627AUG4 employs dielectrically isolated complementary NPN/PNP process technology with laser-trimmed input circuitry to achieve bipolar-class voltage noise performance without sacrificing FET-class input impedance (>10TΩ) or bias current. Its cascode input stage maintains sub-picoampere IB across ±11.5V common-mode range.

This device uses a fully compensated internal architecture enabling stable operation at unity gain, distinguishing it from the higher-bandwidth OPA637 (gain ≥ 5 only). Its open-loop gain exceeds 120dB and PSRR reaches 117dB, supporting precision DC-coupled applications where supply ripple rejection and thermal stability are critical.

Key Specifications

Pinout & Package

OPA627AUG4 is packaged in an 8-pin SOIC (D package), surface-mountable with standard JEDEC MS-012AC footprint. Pin 1, 5, and 8 are no-connect terminals; pins 2 and 3 serve differential inputs; pin 4 is V–; pin 6 is output; pin 7 is V+.

Key Features

Applications

Equivalent & Alternatives

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

Compared with OPA637AU and ADA4625-1ARZ, the OPA627AUG4 uniquely balances ultra-low IB (<5pA), low VOS (<125µV), and guaranteed unity-gain stability - making it the preferred choice for precision, high-impedance, DC-critical signal chains where layout simplicity and robustness outweigh marginal bandwidth gains.

Availability

OPA627AUG4 is available at Aetrix Electronics and suitable for precision instrumentation, fast data acquisition, and DAC output buffering requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for OPA627AUG4 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 op amp design and manufacturing.

The OPA627AUG4 belongs to TI's OPA6x7 family of high-speed JFET-input op amps, engineered specifically for applications demanding simultaneous low noise, low drift, low input bias current, and unity-gain stability in industrial and test equipment signal paths.

FAQ

What is the maximum operating supply voltage for the OPA627AUG4?

The OPA627AUG4 supports dual-supply operation from ±4.5V to ±18V, corresponding to a total supply span of 36V. Absolute maximum ratings specify ±18V - exceeding this risks permanent damage. For reliable long-term operation, TI recommends staying within ±15V under typical conditions, especially when driving capacitive loads or operating at elevated temperatures.

Is the OPA627AUG4 unity-gain stable, and what does that mean for circuit design?

Yes, the OPA627AUG4 is explicitly unity-gain stable per TI's datasheet. This means it can be configured as a voltage follower (gain = 1) or integrator without external phase-compensation components. Unlike the OPA637, which requires minimum noise gain of 5, the OPA627AUG4 eliminates stability uncertainty in low-gain sensor interfaces, DAC buffers, and active filters - reducing design iteration and layout sensitivity.

How does the input bias current of the OPA627AUG4 behave across temperature and common-mode voltage?

The OPA627AUG4 maintains ≤±5pA input bias current (IB) over –25°C to +85°C and ±11.5V common-mode range, thanks to its cascode input architecture. At extremes (e.g., –55°C or ±18V supplies), IB may rise to ±10pA. This stability ensures minimal voltage error across high-impedance sources like piezoelectric sensors or pH electrodes without requiring guard traces or active bias cancellation.

Can the OPA627AUG4 drive heavy capacitive loads, and what layout practices improve stability?

The OPA627AUG4 is not optimized for direct capacitive loading >100pF. Driving ADC inputs or cables requires isolation via a series resistor (e.g., 20–50Ω) between OUT and load. Layout best practices include local 0.1µF V+/V– decoupling, symmetric input trace routing, ground plane beneath the SOIC-8 body, and avoiding vias near IN+/IN–. These reduce parasitic inductance and maintain >75° phase margin.

What distinguishes the OPA627AUG4 from the OPA627BM or OPA627SM variants?

The OPA627AUG4 is the SOIC-8 packaged industrial-grade version (AU suffix), rated for –40°C to +125°C operation with ±500µV max VOS and ±2.5µV/°C max drift. In contrast, OPA627BM offers tighter ±100µV VOS and ±0.8µV/°C drift but in TO-99 metal can; OPA627SM extends temperature range to –55°C to +125°C with military-grade screening. All share identical AC specs and pinout - selection depends on accuracy, packaging, and environmental requirements.