Texas Instruments OPA251UA/2K5

Overview

OPA251UA/2K5 from Texas Instruments is a single-channel, micro-power operational amplifier optimized for ±15V dual-supply operation, delivering 25μA quiescent current, ±250μV max input offset voltage, rail-to-rail output swing within 50mV of rails, and 128dB open-loop gain-used in precision signal conditioning for portable test equipment and battery-powered medical instruments.

For engineers reviewing the OPA251UA/2K5 datasheet, OPA251UA/2K5 pinout, OPA251UA/2K5 application, or OPA251UA/2K5 equivalent, key selection criteria include its ±15V-optimized offset trim, 30kHz gain-bandwidth product, 124dB common-mode rejection, low 65nV/√Hz input voltage noise density, and SOIC-8 package compatibility with space-constrained analog front-ends.

Technical Context

The OPA251UA/2K5 implements a bipolar-input, unity-gain-stable op-amp architecture with laser-trimmed offset at ±15V, enabling high DC precision without external trimming in most applications. Its input stage supports common-mode voltage down to (V–) – 0.2V and rail-to-rail output swing under 100mV load conditions.

It features internal compensation for stable operation with capacitive loads up to 200pF at ±15V in unity-gain configuration, and maintains 100dB open-loop gain across –40°C to +125°C operating range while drawing only ±27μA typical quiescent current per amplifier.

Key Specifications

Pinout & Package

OPA251UA/2K5 is housed in an 8-pin SOIC (D package), 3.9mm × 4.9mm body, 1.27mm pitch, with exposed pad not present. Pin 1 and Pin 5 provide external offset trim capability; Pin 8 is no-connect and must remain floating.

Key Features

Applications

Equivalent & Alternatives

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

Compared with OPA251UA/2K5, OPA241UA/2K5 offers better low-voltage performance and drift, while TLV2461CDR trades precision for speed and drive strength-neither is pin-compatible, requiring PCB redesign for substitution.

Availability

OPA251UA/2K5 is available at Aetrix Electronics and suitable for battery-operated instruments, portable medical devices, and industrial sensor signal conditioning requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for OPA251UA/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 and embedded processing technologies, with decades of op-amp innovation and broad industrial qualification.

The OPAx251 family was designed specifically for high-precision, low-power analog signal conditioning in ±15V-based test, measurement, and medical equipment where DC accuracy and long-term stability are critical.

FAQ

What is the maximum supply voltage rating for OPA251UA/2K5?

OPA251UA/2K5 has an absolute maximum supply voltage of ±18V (dual supply) or 36V (single supply). Operation beyond these limits risks permanent damage. Recommended operating range is ±1.35V to ±18V dual or 2.7V to 36V single, with full specifications guaranteed at ±15V and 25°C.

Does OPA251UA/2K5 support rail-to-rail input operation?

No, OPA251UA/2K5 does not support rail-to-rail input. Its input common-mode voltage range extends to (V–) – 0.2V and (V+) – 0.8V, meaning it operates correctly when inputs stay at least 200mV above the negative rail and 800mV below the positive rail. This is sufficient for many single-supply applications but excludes true rail-to-rail input capability.

Can OPA251UA/2K5 drive capacitive loads, and what is the limit?

Yes, OPA251UA/2K5 is unity-gain stable and can drive capacitive loads. At ±15V supply and unity gain, it remains stable with up to ~200pF directly on the output. With higher supply voltages or gain >1, capacitive load drive improves significantly-e.g., up to ~2700pF at ±15V and G = 10. For larger loads, a series resistor (e.g., 5kΩ) in the feedback path restores stability while preserving DC accuracy.

Is external offset trim required when using OPA251UA/2K5?

No, external offset trim is not required for most applications. OPA251UA/2K5 is laser-trimmed at ±15V and specifies ±250μV max input offset voltage-low enough for precision DC amplification without adjustment. Trim pins (1 & 5) are provided only for special cases requiring sub-50μV offset; using them may degrade temperature drift performance and should be avoided unless strictly necessary.

What is the operating temperature range for OPA251UA/2K5?

OPA251UA/2K5 is fully specified from –40°C to +85°C for all electrical parameters. It is also rated to operate continuously from –55°C to +125°C, though certain parameters (e.g., offset voltage, CMRR) are not guaranteed outside the –40°C to +85°C range. Industrial and extended-temperature designs should verify performance at end-point temperatures using TI's typical characteristics curves.