Texas Instruments OPA328DBVR

Overview

OPA328DBVR from Texas Instruments is a single-channel, precision CMOS operational amplifier optimized for low-noise, high-speed signal conditioning in rail-to-rail input/output (RRIO) configurations. It delivers 40MHz gain-bandwidth, 30V/µs slew rate, 50µV max offset voltage, 120dB CMRR, and 1pA max input bias current - enabling high-fidelity analog front-ends for ADC driving in optical modules and patient monitors.

For engineers reviewing the OPA328DBVR datasheet, OPA328DBVR pinout, OPA328DBVR application, or OPA328DBVR equivalent, key selection criteria include its zero-crossover distortion architecture, e-trim™-enabled ultra-low offset stability over temperature, 2.2V–5.5V single-supply operation, and verified 100pF capacitive load drive capability in unity-gain buffer configurations.

Technical Context

The OPA328DBVR employs a proprietary charge-pump–assisted PMOS input stage that extends the input common-mode range 100mV beyond both supply rails while eliminating crossover distortion - ensuring linear CMRR >120dB across full V_CM. Its e-trim™ technology achieves ±50µV max V_OS and ±1µV/°C max drift without auto-zero switching artifacts.

This op amp is unity-gain stable and optimized for transimpedance amplification (<1nA photocurrent) and high-resolution ADC driving (e.g., SAR or sigma-delta), leveraging 6.1nV/√Hz noise at 10kHz and 180ns 0.01% settling time to preserve dynamic range and SNR in precision measurement systems.

Key Specifications

Pinout & Package

OPA328DBVR is housed in a 5-pin SOT-23 (DBV) package with exposed pad thermal enhancement. Pin 1 is OUT; Pin 2 is V−; Pin 3 is +IN; Pin 4 is −IN; Pin 5 is V+.

Key Features

Applications

Equivalent & Alternatives

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

Compared with OPA328DBVR, OPA333AIDBVR trades 2.4× bandwidth and 177× slew rate for 5× lower offset and 10× lower IQ, while ADA4522-1ARMZ sacrifices 13× bandwidth and 17× slew rate to achieve 20× better DC stability - making OPA328DBVR uniquely balanced for high-speed precision measurement where both AC fidelity and DC accuracy matter.

Availability

OPA328DBVR is available at Aetrix Electronics and suitable for optical module design, medical imaging equipment, and analytical instrumentation requiring stable component supply, traceable lot control, and long-term production continuity.

Supply support for OPA328DBVR 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 expertise in precision amplifiers and signal chain solutions.

The OPAx328 family was designed specifically for high-fidelity, high-speed analog signal conditioning in medical diagnostics, optical communications, and industrial process analytics - emphasizing zero-crossover linearity, e-trim™ DC stability, and robust capacitive load drive.

FAQ

What is the maximum capacitive load the OPA328DBVR can drive stably in unity-gain configuration?

The OPA328DBVR remains unity-gain stable with up to 100pF of pure capacitive load, as confirmed in TI's SBOS957G datasheet Figure 5-28. This capability eliminates the need for output isolation resistors when interfacing directly with typical 12–16-bit SAR ADC input capacitances (10–30pF), simplifying PCB layout and preserving signal integrity in high-resolution data acquisition systems using the OPA328DBVR.

Does the OPA328DBVR support true rail-to-rail input operation, and how far beyond the rails does it extend?

Yes, the OPA328DBVR features true rail-to-rail input operation enabled by an internal charge pump, allowing the input common-mode voltage range to extend 100mV beyond both V− and V+ rails. This is explicitly specified in the "Input Voltage" parameter (V_CM = (V−) − 0.1 V to (V+) + 0.1 V) and enables direct interfacing with unbuffered bridge sensors or thermocouples without external level-shifting circuitry in designs using the OPA328DBVR.

What is the guaranteed maximum input offset voltage for the OPA328DBVR over temperature?

The OPA328DBVR has a maximum input offset voltage of ±50µV at TA = 25°C, and a maximum offset drift of ±1µV/°C over the full operating temperature range (–40°C to +125°C), as specified in Section 5.7 of the SBOS957G datasheet. These values are production-tested limits - not typical - ensuring predictable DC performance in precision applications such as CT scanner front-ends and gas analyzer photometric channels using the OPA328DBVR.

Can the OPA328DBVR be used with a single 2.2V supply, and what is its output swing under that condition?

Yes, the OPA328DBVR is fully specified for single-supply operation from 2.2V to 5.5V. At VS = 2.2V with RL = 2kΩ, the output swings within 15mV of each rail (V− and V+), delivering >98% of full-scale voltage range to downstream ADCs. This rail-to-rail output capability maximizes dynamic range in space-constrained, low-voltage portable medical devices relying on the OPA328DBVR.

How does the e-trim™ technology in the OPA328DBVR differ from traditional auto-zero or chopper stabilization?

Unlike auto-zero or chopper amplifiers, the OPA328DBVR's e-trim™ uses nonvolatile memory trimming during final test to permanently calibrate input offset - eliminating clock feedthrough, switching noise, and intermodulation distortion. This preserves wideband performance (40MHz GBW, 6.1nV/√Hz noise) while achieving ±50µV max V_OS, making the OPA328DBVR suitable for both precision DC and high-frequency AC applications without trade-offs inherent to chopping architectures.