Texas Instruments OPA2228PA

Overview

OPA2228PA from Texas Instruments is a dual, high-precision, low-noise operational amplifier optimized for closed-loop gains ≥5, delivering 33 MHz gain-bandwidth product, 11 V/µs slew rate, and 3 nV/√Hz input voltage noise at 1 kHz. It operates from ±2.5 V to ±18 V supplies and targets professional audio preamplification, precision data acquisition front-ends, and spectral analysis instrumentation where AC fidelity and DC accuracy coexist.

For engineers reviewing the OPA2228PA datasheet, OPA2228PA pinout, OPA2228PA application, or OPA2228PA equivalent, key selection criteria include its minimum stable gain of 5 V/V, thermal performance in PDIP-8 (R_θJA = 48.9°C/W), channel separation >110 dB at 1 kHz, and compatibility with ±15 V supply rails in industrial signal conditioning designs.

Technical Context

The OPA2228PA implements a compensated bipolar input stage enabling high open-loop gain (160 dB) and exceptional common-mode rejection (138 dB) while maintaining stability at G ≥ 5. Its current-noise-limited architecture achieves 0.4 pA/√Hz at 1 kHz, supporting high-source-impedance sensor interfaces without degrading SNR.

Unlike the unity-gain-stable OPA2227PA, the OPA2228PA uses internal compensation tailored for higher closed-loop bandwidth-achieving 1.5 µs 0.1% settling time at G = 5 with 100 pF load-making it unsuitable for unity-gain buffers but optimal for fixed-gain instrumentation amplifiers and active filter stages.

Key Specifications

Pinout & Package

OPA2228PA is supplied in an 8-pin PDIP (plastic dual in-line package) with body size 9.81 mm × 6.35 mm, rated for through-hole mounting and manual rework. Thermal resistance is R_θJA = 48.9°C/W, supporting continuous operation at ambient temperatures up to 75°C with no forced airflow.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar high-speed, low-noise operational amplifier applications.

Compared with OPA2227PA and AD827ARZ, the OPA2228PA uniquely balances 33 MHz bandwidth, 3 nV/√Hz noise, and 138 dB CMRR-making it optimal for fixed-gain, high-fidelity signal chains where both AC response and DC precision are non-negotiable.

Availability

OPA2228PA is available at Aetrix Electronics and suitable for professional audio equipment, precision data acquisition systems, and spectral analysis instrumentation requiring stable component supply across extended production lifecycles.

Supply support for OPA2228PA 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 company headquartered in Dallas, Texas, specializing in analog and embedded processing technologies with over 90 years of innovation in precision amplifiers and signal chain solutions.

The OPAx22x product line was designed specifically for applications demanding simultaneous high AC performance and precision DC accuracy-targeting professional audio, test & measurement, and industrial sensing markets where noise, drift, and bandwidth must all be simultaneously optimized.

FAQ

What is the minimum closed-loop gain required for stable operation of the OPA2228PA?

The OPA2228PA requires a minimum closed-loop gain of 5 V/V for stable operation. Attempting unity-gain or G = 2 configurations will cause peaking and potential oscillation due to its internal compensation optimized for higher gains. Always verify phase margin in simulation when using non-standard feedback topologies. The OPA2228PA datasheet explicitly states "Minimum Closed-Loop Gain: 5 V/V" in Section 6.7.

Can the OPA2228PA operate from a single +5 V supply?

Yes, the OPA2228PA can operate from a single +5 V supply (V+ = +5 V, V– = 0 V), as its specified operating range extends from ±2.5 V to ±18 V-equivalent to 5 V to 36 V total supply. However, output swing is limited to approximately (V–)+2 V to (V+)–2 V, so expect ~2 V to ~3 V output range. Input common-mode range also shifts accordingly, requiring careful biasing of input signals within that window.

How does the OPA2228PA's noise performance compare to the OPA2227PA?

The OPA2228PA and OPA2227PA share identical noise specifications: 3 nV/√Hz voltage noise at 1 kHz and 0.4 pA/√Hz current noise. Both devices belong to the same OPAx22x family and use matched bipolar input stages. The key distinction lies in bandwidth and stability-not noise-so system-level noise contribution is equivalent when used within their respective stable gain ranges.

Is the OPA2228PA pin-compatible with industry-standard op-amps like the OP-37?

Yes, the OPA2228PA is a pin-for-pin replacement for the OP-37 in PDIP-8 and SOIC-8 packages, as confirmed in the TI datasheet Section 1: "The OPAx227 and OPAx228 series operational amplifiers are pin-for-pin replacements for the industry standard OP-27 and OP-37." This includes identical pin 1–8 assignments for dual variants, enabling drop-in upgrades without PCB changes.

What thermal considerations apply when using the OPA2228PA in a PDIP-8 package at full ±15 V supply?

At ±15 V supply and 0 mA load, the OPA2228PA draws ~4.2 mA per amplifier (8.4 mA total), dissipating ~126 mW. With R_θJA = 48.9°C/W for PDIP-8, junction temperature rise is ~6.2°C above ambient. For ambient temperatures up to 75°C, T_J remains well below the 150°C absolute maximum, confirming safe operation without heatsinking in typical industrial enclosures.