Texas Instruments OPA325IDBVR

Overview

OPA325IDBVR from Texas Instruments is a precision rail-to-rail input/output CMOS operational amplifier optimized as an ADC input driver. It delivers 10 MHz bandwidth, 5 V/µs slew rate, 9 nV/√Hz input voltage noise at 10 kHz, ±150 µV max input offset voltage, and operates from 2.2 V to 5.5 V single supply - enabling high-fidelity signal conditioning in battery-powered SAR ADC front-ends.

For engineers reviewing the OPA325IDBVR datasheet, OPA325IDBVR pinout, OPA325IDBVR application, or OPA325IDBVR equivalent, key selection criteria include zero-crossover distortion performance across rail-to-rail common-mode range, low quiescent current (650 µA/ch), and verified stability driving capacitive loads up to 15 pF in unity-gain buffer configurations.

Technical Context

The OPA325IDBVR employs an internal charge pump to bias a single linear differential pair, eliminating crossover distortion and sustaining 114 dB typical CMRR over full input common-mode range (V– – 0.1 V to V+ + 0.1 V). Its e-trim™ process achieves 150 µV max V_OS with 7.5 µV/°C drift over –40°C to +125°C.

Designed for precision DC-coupled signal chains, it features 10 MHz gain-bandwidth product, unity-gain stability, 10 mV rail-to-rail output swing (RL = 10 kΩ), and 0.2 pA typical input bias current - making it suitable for high-impedance sensor interfaces and transimpedance amplifiers where leakage and offset errors must be minimized.

Key Specifications

Pinout & Package

SOT-23-5 (DBV) package: 2.90 mm × 1.60 mm body, 0.95 mm height, gull-wing leads, RoHS-compliant, moisture sensitivity level 1.

Key Features

Applications

Equivalent & Alternatives

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

Compared with OPA333AIDBVR and ADA4522-1ARMZ, the OPA325IDBVR uniquely balances 10 MHz bandwidth, 650 µA IQ, and zero-crossover linearity - making it the optimal choice for battery-powered, medium-speed precision signal chains where both AC fidelity and DC accuracy matter.

Availability

OPA325IDBVR is available at Aetrix Electronics and suitable for high-Z sensor interfaces, SAR ADC front-ends, and industrial analog input modules requiring stable component supply, long-term lifecycle support, and traceable sourcing.

Supply support for OPA325IDBVR 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 specializing in analog and embedded processing technologies, with leadership in precision amplifiers, data converters, and power management ICs.

The OPA325IDBVR belongs to TI's OPAx325 family of e-trim™ zero-crossover op amps, designed specifically for high-resolution data acquisition systems where rail-to-rail input linearity, low noise, and low power must coexist without compromise.

FAQ

What is the maximum capacitive load the OPA325IDBVR can drive stably in unity-gain configuration?

The OPA325IDBVR is unity-gain stable with capacitive loads up to 15 pF, as verified in the datasheet's Typical Characteristics (Figure 27). This allows direct connection to SAR ADC input capacitors without series isolation resistors - preserving signal integrity and simplifying layout. Exceeding 15 pF may cause peaking or ringing; for heavier loads, external compensation or a small series resistor (e.g., 10 Ω) is recommended. The OPA325IDBVR's internal design inherently supports this drive capability without requiring external components under standard conditions.

Does the OPA325IDBVR require dual supplies, or can it operate from a single 3.3 V rail?

The OPA325IDBVR operates from a single 3.3 V supply - its specified single-supply range is 2.2 V to 5.5 V. It features true rail-to-rail input (V_CM = V– – 0.1 V to V+ + 0.1 V) and output (V_OUT swings within 10 mV of both rails), making it ideal for 3.3 V systems like portable instrumentation and IoT sensor nodes. No dual supply is needed; V– connects to ground, V+ to 3.3 V. The internal charge pump enables this performance without external voltage boosting circuitry.

How does the zero-crossover architecture of the OPA325IDBVR improve performance versus traditional rail-to-rail input op amps?

The OPA325IDBVR uses an internal charge pump to power a single linear input differential pair, eliminating the offset discontinuity seen in conventional complementary-input CMOS op amps during rail transitions. This zero-crossover architecture sustains 114 dB typical CMRR across the full input common-mode range - unlike traditional parts that degrade to <80 dB near the rails. As a result, the OPA325IDBVR maintains precision in DC-coupled sensor interfaces and ADC drivers where input signals span near-ground to near-V+, ensuring consistent accuracy without software correction or range partitioning.

What is the input bias current specification for the OPA325IDBVR, and why is it important in high-impedance applications?

The OPA325IDBVR has a typical input bias current of ±0.2 pA and a maximum of ±10 pA at 25°C (±10 nA over –40°C to +125°C). This ultra-low IB minimizes voltage error across high-value source impedances - for example, a 10 MΩ sensor resistance introduces only 0.1 µV offset error at 25°C. In transimpedance amplifiers or pH probe interfaces, such low IB prevents signal corruption and eliminates need for guard traces or active guarding, directly improving measurement repeatability and reducing system complexity. The OPA325IDBVR's CMOS input stage enables this performance while retaining 10 MHz bandwidth.

Can the OPA325IDBVR be used as a replacement for the OPA333 in existing designs?

The OPA325IDBVR is not a drop-in replacement for the OPA333 due to fundamental architectural differences: the OPA333 is a zero-drift auto-zero op amp (350 kHz GBW, 17 µV max V_OS), while the OPA325IDBVR is a zero-crossover precision op amp (10 MHz GBW, 150 µV max V_OS). Pinout is identical (SOT-23-5), but bandwidth, noise, and drift behavior differ significantly. Substituting OPA325IDBVR for OPA333 would improve speed and AC performance but increase offset and drift - requiring revalidation of DC accuracy. Use OPA325IDBVR only when bandwidth and linearity outweigh ultra-low drift requirements.