Texas Instruments OPA2228UA/2K5G4

Overview

OPA2228UA/2K5G4 from Texas Instruments is a dual-channel, high-precision, low-noise operational amplifier optimized for closed-loop gains ≥5, delivering 33 MHz unity-gain bandwidth, 10 V/µs slew rate, and 138 dB CMRR in an SOIC-8 package. It serves as a pin-for-pin upgrade to OP27/OP37 in professional audio preamps, spectrum analyzer front-ends, and industrial data acquisition systems requiring simultaneous AC fidelity and DC accuracy.

For engineers reviewing the OPA2228UA/2K5G4 datasheet, OPA2228UA/2K5G4 pinout, OPA2228UA/2K5G4 application, or OPA2228UA/2K5G4 equivalent, key selection criteria include minimum closed-loop gain (5 V/V), input offset voltage (±75 µV max), voltage noise density (3 nV/√Hz at 1 kHz), thermal performance in SOIC-8 (R_θJA = 101.9 °C/W), and compatibility with ±2.5 V to ±18 V dual supplies.

Technical Context

The OPA2228UA/2K5G4 implements a compensated bipolar input stage optimized for stability at closed-loop gains of 5 or higher-unlike the unity-gain-stable OPA227 family. Its architecture delivers wide bandwidth via enhanced transconductance while maintaining precision DC parameters including 160 dB open-loop gain and ±10 nA input bias current.

It features dual independent amplifiers sharing common supply rails (V+ and V−), with no internal connection on pins 1 and 5 per SOIC-8 pinout. The device operates across –40°C to +85°C and supports rail-to-rail output swing within 2 V of each supply under 10 kΩ load.

Key Specifications

Pinout & Package

OPA2228UA/2K5G4 is housed in an 8-pin SOIC (SO-8) package with exposed pad not electrically connected. Thermal resistance is R_θJA = 101.9 °C/W, R_θJC(top) = 46.3 °C/W, and R_θJB = 45.5 °C/W.

Key Features

Applications

Equivalent & Alternatives

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

Compared with OPA2228UA/2K5G4, OPA2227UA/2K5 trades bandwidth and slew rate for unconditional stability, while AD8620ARZ sacrifices voltage noise performance to achieve sub-picoampere input bias-making each alternative optimal only under distinct signal-chain constraints.

Availability

OPA2228UA/2K5G4 is available at Aetrix Electronics and suitable for professional audio equipment, spectrum analyzers, and industrial data acquisition systems requiring stable component supply, long-term lifecycle support, and guaranteed traceability.

Supply support for OPA2228UA/2K5G4 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 OPAx228 product line was engineered specifically for high-fidelity signal chains demanding both wide bandwidth and sub-100 µV offset-targeting test & measurement, professional audio, and industrial DAQ applications where AC and DC performance must coexist.

FAQ

What is the minimum closed-loop gain required for stable operation of the OPA2228UA/2K5G4?

The OPA2228UA/2K5G4 requires a minimum closed-loop gain of 5 V/V for stable operation. Unlike unity-gain-stable amplifiers such as the OPA2227, it is not designed for G = 1 configurations. Attempting unity-gain use may cause peaking or oscillation. Stability is ensured only when configured for gains ≥5, as verified in TI's SBOS110C datasheet Figure 6-23 and Section 7.1.

Does the OPA2228UA/2K5G4 support single-supply operation?

Yes, the OPA2228UA/2K5G4 supports single-supply operation from 4.5 V to 36 V (VS = V+ – V−), per Section 6.3 of the datasheet. However, its input common-mode range is limited to (V−) + 2 V to (V+) – 2 V, and output swing is typically (V−) + 2 V to (V+) – 2 V under 10 kΩ load-so proper level-shifting or reference biasing is required for true rail-to-rail signal handling in single-supply designs.

What is the thermal resistance (R_θJA) of the OPA2228UA/2K5G4 in its SOIC-8 package?

The OPA2228UA/2K5G4 in SOIC-8 (U-grade) has a junction-to-ambient thermal resistance (R_θJA) of 101.9 °C/W, as specified in Table 6.5 of the SBOS110C datasheet. This value assumes standard JEDEC 2S2P board layout; actual thermal performance improves with copper pour, thermal vias, and airflow-critical for sustained operation near +85°C ambient.

Can the OPA2228UA/2K5G4 drive a 600 Ω load effectively?

Yes, the OPA2228UA/2K5G4 can drive a 600 Ω load to ±3.5 V while maintaining <0.00005% THD+N at 1 kHz (Section 6.8). Its short-circuit current rating is ±45 mA, supporting peak currents needed for low-Z audio line driving. For continuous 600 Ω operation, ensure junction temperature remains below 125°C using appropriate PCB copper area and ambient derating.

Is the OPA2228UA/2K5G4 pin-compatible with legacy OP27 or OP37 op amps?

Yes-the OPA2228UA/2K5G4 is explicitly documented as a pin-for-pin replacement for industry-standard OP27 and OP37 dual op amps (Section 3, SBOS110C). It retains identical SOIC-8 pinout (Out A, –In A, +In A, V−, +In B, –In B, Out B, V+), enabling drop-in upgrades with substantial improvements in bandwidth (33 MHz vs. 8 MHz), slew rate (10 V/µs vs. 2.8 V/µs), and noise (3 nV/√Hz vs. 3.8 nV/√Hz).