Texas Instruments OPA347NA/250

Overview

OPA347NA/250 from Texas Instruments is a single-channel, microPower rail-to-rail input/output operational amplifier in SOT-23-5 package. It delivers 350kHz gain-bandwidth, 20µA quiescent current, and operates from 2.3V to 5.5V single supply - enabling precision signal conditioning in space-constrained, battery-powered smoke detectors and 2-wire transmitters.

For engineers reviewing the OPA347NA/250 datasheet, OPA347NA/250 pinout, OPA347NA/250 application, or OPA347NA/250 equivalent, key selection criteria include rail-to-rail I/O swing (within 5mV of rails at light load), ultra-low IQ for multi-year battery life, input common-mode range extending 200mV beyond rails, and guaranteed operation from –55°C to +125°C.

Technical Context

The OPA347NA/250 employs a complementary differential input stage (N- and P-channel pairs) to achieve rail-to-rail input operation, with a 400mV transition region where both pairs are active - requiring careful biasing in high-precision DC applications. Its class AB output stage supports rail-to-rail output swing down to 5mV from supply rails under 100kΩ load.

It is unity-gain stable and optimized for driving medium-speed ADCs like the ADS7822, with low input bias current (±0.5pA typ), 60nV/√Hz input voltage noise density at 1kHz, and capacitive load drive up to 250pF in unity-gain configuration without external compensation.

Key Specifications

Pinout & Package

SOT-23-5 surface-mount package (DBV drawing), 2.9mm × 1.6mm footprint, moisture sensitivity level (MSL) Level-2 (260°C peak reflow).

Key Features

Applications

Equivalent & Alternatives

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

Compared with MCP6001T-I/OT and TLV2461IDBVR, the OPA347NA/250 uniquely balances sub-25µA quiescent current, 2.3V operation, and –55°C to +125°C qualification - making it the only viable option for ultra-low-power, wide-temperature, single-cell–compatible designs.

Availability

OPA347NA/250 is available at Aetrix Electronics and suitable for smoke detectors, 2-wire transmitters, and portable medical monitors requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for OPA347NA/250 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 low-power signal chains.

The OPA347 series belongs to TI's precision microPower op amp portfolio, designed specifically for battery-operated safety-critical sensors and industrial field devices demanding rail-to-rail operation and extreme temperature resilience.

FAQ

What is the minimum supply voltage for reliable operation of the OPA347NA/250?

The OPA347NA/250 is fully specified and ensured to operate down to 2.3V, with functional operation confirmed as low as 2.3V across the full –55°C to +125°C temperature range. At 2.3V, key parameters including gain-bandwidth (350kHz), input offset voltage (≤7mV), and output swing remain within datasheet limits - making it suitable for aging battery applications where voltage drops below 2.5V.

Does the OPA347NA/250 require external compensation for stability with capacitive loads?

The OPA347NA/250 is unity-gain stable and can directly drive up to 250pF of pure capacitive load without external compensation. For loads exceeding 250pF, TI recommends adding a 10Ω–20Ω series resistor between the output and capacitive load - a solution validated in the OPA347 datasheet Figure 6 and used in ADS7822 ADC interface reference designs.

How does the rail-to-rail input architecture of the OPA347NA/250 affect precision in DC-coupled applications?

The OPA347NA/250 uses complementary N- and P-channel input stages, creating a 400mV transition region near (V+) – 1.3V where both pairs conduct. Within this region, PSRR, CMRR, and offset voltage degrade - so for highest DC precision, bias the common-mode voltage outside this zone (e.g., < (V+) – 1.7V or > (V+) – 0.9V). The datasheet provides CMRR specifications both inside and outside this region to guide design.

Can the OPA347NA/250 be used in photodiode transimpedance amplifier circuits?

Yes - the OPA347NA/250 is well-suited for photodiode TIA applications due to its ultra-low input bias current (±0.5pA typ), rail-to-rail output, and 350kHz bandwidth. Its input stage tolerates common-mode voltages up to (V+) + 0.2V, allowing virtual-ground node placement at V+ for reverse-biased photodiodes. Layout best practices (guard rings, low-leakage PCB materials) are essential to preserve pA-level accuracy.

What is the thermal resistance (θ_JA) of the OPA347NA/250 in its SOT-23-5 package?

The OPA347NA/250 in the SOT-23-5 (DBV) package has a junction-to-ambient thermal resistance (θ_JA) of 200°C/W under standard JEDEC test conditions. This value assumes a 2-layer PCB with minimal copper pour; adding thermal vias and copper planes beneath the exposed pad (if present) can reduce effective θ_JA by 30–50%, critical for sustained operation at +125°C ambient.