Texas Instruments OPA342UA

Overview

OPA342UA from Texas Instruments is a single-channel, rail-to-rail input/output CMOS operational amplifier optimized for low-power, single-supply operation down to 2.7V. It delivers 1MHz gain-bandwidth, 1V/µs slew rate, and 150µA typical quiescent current, with output swing within 1mV of rails under light load - making it ideal for driving sampling ADCs in portable data acquisition systems.

For engineers reviewing the OPA342UA datasheet, OPA342UA pinout, OPA342UA application, or OPA342UA equivalent, key selection criteria include its rail-to-rail input common-mode range extending 300mV beyond supplies, THD+N of 0.006% at 1kHz, and SO-8 package compatibility with space-constrained industrial and audio signal conditioning designs.

Technical Context

The OPA342UA employs a complementary differential input stage (N- and P-channel pairs) enabling rail-to-rail input operation, with a 400mV transition region where both pairs conduct - requiring biasing awareness in precision DC applications. Its class AB output stage supports rail-to-rail swing into loads ≥100kΩ while maintaining ≥104dB open-loop gain.

Specified over –40°C to +85°C and supply voltages from 2.7V to 5.5V, the device achieves 76–88dB CMRR (depending on VCM and VS), 200µV/V PSRR, and 30nV/√Hz input voltage noise density at 1kHz - confirming suitability for low-noise, battery-powered analog front-ends interfacing with 12-bit ADCs like ADS7822.

Key Specifications

Pinout & Package

OPA342UA is housed in an 8-pin SOIC (SO-8) package per JEDEC MS-012, with thermal resistance θ_JA = 150°C/W. Pin 1 is located at the top-left corner adjacent to the index mark.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar operational amplifier applications.

Compared with OPA333AIDBVR and MCP6001T-E/OT, the OPA342UA uniquely balances 1MHz bandwidth, 1mV rail-to-rail output, 150µA quiescent current, and proven ADC-driving capability - making it optimal for portable, battery-powered signal chains demanding both precision and speed.

Availability

OPA342UA is available at Aetrix Electronics and suitable for portable data acquisition, single-supply audio preamplification, and industrial sensor interface applications requiring stable component supply and long-term production continuity.

Supply support for OPA342UA 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 op amps and signal chain solutions.

The OPA342UA belongs to TI's MicroAmplifier™ series - designed specifically for low-cost, low-power, miniature applications requiring rail-to-rail performance and single-supply operation from 2.7V.

FAQ

What is the maximum capacitive load the OPA342UA can drive in unity-gain configuration?

The OPA342UA can directly drive up to 250pF of pure capacitive load in unity-gain configuration while maintaining stability. For larger loads, a 10Ω–20Ω series resistor between the output and capacitive load improves phase margin without degrading DC accuracy - a technique validated in TI's SBOS106A datasheet Figure 5. This capability makes the OPA342UA well-suited for driving ADC input capacitance without external compensation networks.

Does the OPA342UA support true rail-to-rail output swing under all load conditions?

The OPA342UA achieves rail-to-rail output swing within 1mV of V+ or V– only with resistive loads ≥100kΩ. With 5kΩ loads, output swing degrades to within 20–400mV of the rails depending on temperature and supply voltage. The datasheet specifies "within 1mV" conditionally - engineers must verify load impedance in their design to ensure required dynamic range. This behavior is inherent to its class AB output stage topology.

What is the input common-mode voltage range of the OPA342UA, and how does it affect circuit design?

The OPA342UA features a rail-to-rail input stage with common-mode range extending 300mV beyond both supply rails (–0.3V to V+ + 0.3V). However, a 400mV transition region near V+ – 1.3V exhibits degraded PSRR, CMRR, and THD. To avoid performance loss, designers should bias non-inverting inputs below this region or use inverting configurations with fixed common-mode voltage - guidance detailed in SBOS106A Application Information section.

Can the OPA342UA operate from a 2.5V supply despite the datasheet specifying 2.7V minimum?

The OPA342UA is fully specified and guaranteed from 2.7V to 5.5V; operation at 2.5V falls outside the characterized range. While some units may function at 2.5V, parameters including GBW, slew rate, output swing, and CMRR are not assured. TI explicitly states "optimized to operate on a single supply as low as 2.5V" in descriptive text, but all electrical specifications apply only from 2.7V - making 2.7V the validated minimum for production designs using OPA342UA.

How does the OPA342UA's input bias current compare to other CMOS op amps, and why does it matter?

The OPA342UA has an input bias current of ±0.2pA (typ), among the lowest in its class - critical for high-impedance sensor interfaces (e.g., pH electrodes, photodiode transimpedance stages) where bias current-induced offset and drift dominate error. At 25°C, this value remains stable across voltage and temperature, unlike bipolar-input op amps; however, it rises to ~10pA at +85°C, a factor requiring consideration in wide-temperature industrial deployments using OPA342UA.