Texas Instruments OPA2228UA

Overview

OPA2228UA from Texas Instruments is a dual, high-precision, low-noise operational amplifier optimized for closed-loop gains ≥5. It delivers 33 MHz gain-bandwidth product, 11 V/µs slew rate, 3 nV/√Hz input voltage noise at 1 kHz, 138 dB CMRR, and ±75 µV max input offset voltage across –40°C to 85°C. It is used in professional audio preamplifiers, spectral analysis front-ends, and precision data acquisition systems requiring simultaneous AC fidelity and DC accuracy.

For engineers reviewing the OPA2228UA datasheet, OPA2228UA pinout, OPA2228UA application, or OPA2228UA equivalent, key selection criteria include closed-loop gain stability (≥5), thermal drift performance (±0.3 µV/°C max), supply flexibility (±2.5 V to ±18 V), and SOIC-8 package compatibility with legacy OP-37 layouts.

Technical Context

The OPA2228UA employs a compensated bipolar input stage enabling stable operation at closed-loop gains of 5 V/V or higher, with no need for external compensation in standard configurations. Its architecture suppresses output phase reversal and supports rail-to-rail output swing within ±3.5 V of supplies into 600 Ω loads.

It features matched input bias currents (±10 nA max), ultra-low 1/f noise corner (<10 Hz), and robust PSRR (120 dB) and CMRR (138 dB) over frequency - critical for rejecting power supply ripple and common-mode interference in sensitive analog signal chains.

Key Specifications

Pinout & Package

OPA2228UA is housed in an 8-pin SOIC (SO-8) package measuring 4.90 mm × 3.91 mm, with standard dual op-amp pinout compatible with industry footprint requirements.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar dual high-precision op-amp applications.

Compared with OPA2228UA, OPA228U offers identical performance in reel format for production lines, while LT1037CN8#PBF sacrifices bandwidth and noise for guaranteed G = 1 stability and user-adjustable offset - making it viable only in legacy designs where OPA2228UA's minimum gain requirement (G ≥ 5) cannot be met.

Availability

OPA2228UA is available at Aetrix Electronics and suitable for professional audio equipment, spectral analysis instruments, and geophysical data loggers requiring stable component supply with guaranteed long-term manufacturability.

Supply support for OPA2228UA 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 OPAx22x product line was engineered specifically for high-fidelity analog signal chains demanding simultaneous low-noise AC response and precision DC accuracy - targeting audio, test & measurement, and scientific instrumentation.

FAQ

What is the minimum closed-loop gain required for stable operation of the OPA2228UA?

The OPA2228UA is optimized for closed-loop gains of 5 V/V or greater. Operation below G = 5 may result in peaking or instability due to its internal compensation. For unity-gain or low-gain applications, the OPA2227UA or OPA227UA should be selected instead. This gain constraint is inherent to the OPA2228UA's design and is specified in the Electrical Characteristics table under "Minimum Closed-Loop Gain".

Does the OPA2228UA include offset voltage trim pins?

No, the OPA2228UA does not feature offset trim pins. Unlike the single-channel OPA228 (which has Pins 1 and 8 for offset adjustment), the dual-channel OPA2228UA uses laser-trimmed internal circuitry to achieve ±75 µV maximum input offset voltage without external trimming. This simplifies PCB layout and eliminates the need for potentiometers or precision resistors in production designs.

Can the OPA2228UA operate on asymmetric supply voltages such as +15 V and –5 V?

Yes, the OPA2228UA supports asymmetric supplies. Its absolute maximum rating allows up to 36 V total supply range (V+ – V–), and recommended operation spans ±2.5 V to ±18 V. A configuration like +15 V and –5 V (20 V total) falls well within specification and maintains full performance, including output swing and CMRR, provided both supplies remain within their respective voltage limits relative to ground.

What is the typical input voltage noise density of the OPA2228UA at 10 Hz?

The typical input voltage noise density of the OPA2228UA at 10 Hz is 3.5 nV/√Hz, as confirmed in the Electrical Characteristics table under "NOISE" for the OPAx228 Series. This value reflects the device's low 1/f noise corner and contributes to its suitability for precision DC-coupled applications where low-frequency noise dominates system error budgets.

Is the OPA2228UA pin-compatible with the OP-37GP?

Yes, the OPA2228UA is a pin-for-pin replacement for the OP-37GP in SOIC-8 packages, as explicitly stated in the datasheet's "Features" section: "OPA228 replaces OP-37". Both devices share identical pin functions (Out A, –In A, +In A, V–, +In B, –In B, Out B, V+), enabling drop-in upgrades without PCB modification - provided the application meets the OPA2228UA's minimum gain requirement of 5 V/V.