Texas Instruments OPA2228UG4

Overview

OPA2228UG4 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-compatible upgrade to OP27/OP37 in professional audio preamps, spectrum analyzer front-ends, and precision data acquisition systems requiring simultaneous AC fidelity and DC accuracy.

For engineers reviewing the OPA2228UG4 datasheet, OPA2228UG4 pinout, OPA2228UG4 application, or OPA2228UG4 equivalent, key selection criteria include its minimum stable gain of 5 V/V, 3 nV/√Hz input voltage noise at 1 kHz, ±2.5 V to ±18 V dual-supply operation, and guaranteed 75 µV max input offset voltage across –40°C to +85°C.

Technical Context

The OPA2228UG4 implements a compensated bipolar input stage with internal offset trim capability, enabling high open-loop gain (160 dB) and exceptional common-mode rejection without external compensation. Its architecture prioritizes speed and stability in non-inverting and inverting configurations where closed-loop gain exceeds 5, avoiding peaking or oscillation seen in unity-gain setups.

Unlike the OPA2227 variant, the OPA2228UG4 uses a higher-transconductance output stage and modified compensation network to achieve 33 MHz bandwidth and 10 V/µs slew rate-while maintaining low 10 nA max input bias current and 0.4 pA/√Hz input current noise density at 1 kHz.

Key Specifications

Pinout & Package

OPA2228UG4 is housed in an 8-pin SOIC (SO-8) package with standard dual-opamp pinout and no internal connections on pins 4 (V−) and 8 (V+), supporting surface-mount assembly and thermal performance of R_θJA = 101.9°C/W.

Key Features

Applications

Equivalent & Alternatives

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

Compared with OPA2227UG4, the OPA2228UG4 trades unity-gain stability for 4× higher bandwidth and 4× faster slew rate-making it optimal for gain ≥5 signal chains. Against AD8620ARZ, it provides lower cost and higher output drive while accepting higher input bias current, aligning with bipolar-sensor interfacing needs.

Availability

OPA2228UG4 is available at Aetrix Electronics and suitable for professional audio equipment, spectrum analyzer subsystems, and precision data acquisition systems requiring stable component supply with long-term industrial lifecycle support.

Supply support for OPA2228UG4 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.

The OPAx22x series-including OPA2228UG4-is engineered for mixed-signal applications demanding both wideband AC performance and sub-100-µV DC precision, targeting test & measurement, audio, and industrial sensing markets.

FAQ

What is the minimum closed-loop gain required for stable operation of the OPA2228UG4?

The OPA2228UG4 requires a minimum closed-loop gain of 5 V/V for stable operation. Unlike unity-gain stable amplifiers such as the OPA2227UG4, it is internally compensated for higher gains to achieve its 33 MHz bandwidth and 10 V/µs slew rate. Using it at G < 5 may cause peaking or oscillation; always verify phase margin in simulation or bench testing when operating near the stability boundary.

Does the OPA2228UG4 support single-supply operation?

Yes, the OPA2228UG4 supports single-supply operation from 4.5 V to 36 V, as specified in its Recommended Operating Conditions. Input common-mode range extends to (V–) + 2 V and (V+) – 2 V, and output swings within 2 V of each rail under 10 kΩ load-enabling use in 5-V or 12-V systems with proper level-shifting or rail-splitting networks.

How does the input offset voltage specification of the OPA2228UG4 compare across temperature?

The OPA2228UG4 has a maximum input offset voltage of ±75 µV at +25°C and ±100 µV over the full –40°C to +85°C operating range (U-grade). Its offset drift is limited to ±0.6 µV/°C max, meaning total drift over the full temperature span is ≤60 µV-ensuring predictable calibration behavior in unheated industrial enclosures.

Can the OPA2228UG4 drive capacitive loads directly?

The OPA2228UG4 can drive moderate capacitive loads, but stability degrades above ~100 pF without isolation resistance. For loads >100 pF (e.g., coaxial cables or ADC input capacitance), add a 20–100 Ω series resistor between output and load to maintain phase margin. Figure 6-31 in the datasheet shows overshoot vs load capacitance for various gains, confirming need for compensation above 50 pF in G = ±10 configurations.

Is the OPA2228UG4 pin-compatible with legacy OP27 or OP37 op amps?

Yes, the OPA2228UG4 is a direct pin-for-pin replacement for the dual-channel OP27 and OP37 in SOIC-8 packages, offering substantial improvements including 33 MHz bandwidth (vs 8 MHz for OP27), 10 V/µs slew rate (vs 2.8 V/µs), and lower 3 nV/√Hz noise (vs 3.5 nV/√Hz). No PCB changes are required-only verify that system gain meets the OPA2228UG4's minimum G = 5 requirement.