Texas Instruments OPA347PA

Overview

OPA347PA from Texas Instruments is a single-channel, microPower rail-to-rail input/output operational amplifier in an 8-pin PDIP package. It delivers 350kHz gain-bandwidth, 20µA quiescent current, rail-to-rail operation from 2.3V to 5.5V supply, and input voltage range extending 200mV beyond rails-ideal for low-voltage battery-powered smoke detectors and portable instrumentation.

For engineers reviewing the OPA347PA datasheet, OPA347PA pinout, OPA347PA application, or OPA347PA equivalent, key selection criteria include ultra-low IQ, guaranteed rail-to-rail I/O swing at 2.3V, –55°C to +125°C temperature rating, DIP-8 through-hole compatibility for prototyping, and verified performance driving ADC inputs in 2-wire transmitters.

Technical Context

The OPA347PA uses a complementary differential input stage (N- and P-channel pairs) enabling rail-to-rail common-mode input range from (V–) – 0.2V to (V+) + 0.2V. Its class AB output stage achieves 5mV rail-to-rail swing into 100kΩ loads and sustains 100dB open-loop gain at 5.5V with 100kΩ load.

It is unity-gain stable, supports single-supply operation down to 2.3V, and features 60dB PSRR and 70dB CMRR over its full common-mode range below the transition region. Input bias current is ±0.5pA typical, and it drives up to 250pF capacitive loads directly in unity-gain configuration.

Key Specifications

Pinout & Package

DIP-8 (PDIP) package: 0.3-inch wide, through-hole, industry-standard footprint compatible with breadboards and legacy PCB layouts.

Key Features

Applications

Equivalent & Alternatives

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

Compared with OPA347UA and TLV2461CP, the OPA347PA uniquely balances ultra-low 20µA quiescent current, rail-to-rail I/O at 2.3V, and DIP-8 mechanical compatibility - making it irreplaceable for low-power prototyping and through-hole sensor interface designs where power and form factor are co-constrained.

Availability

OPA347PA is available at Aetrix Electronics and suitable for smoke detectors, 2-wire transmitters, and battery-powered portable instrumentation requiring stable component supply and long-lifecycle support.

Supply support for OPA347PA 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 op amp innovation and broad industrial qualification.

The OPA347 family was designed specifically for ultra-low-power, rail-to-rail signal conditioning in portable and battery-critical systems - emphasizing micropower operation, wide supply range, and robust performance across extreme temperatures.

FAQ

What is the minimum operating voltage for the OPA347PA?

The OPA347PA operates down to 2.3V supply voltage, verified across its full –55°C to +125°C temperature range. This enables direct use with single Li-ion cells (2.7–4.2V) or two alkaline cells (2.4–3.2V), and supports brown-out tolerant designs where supply may dip near 2.3V before shutdown. The OPA347PA maintains rail-to-rail input/output functionality and 350kHz bandwidth at this minimum voltage.

Does the OPA347PA support rail-to-rail input and output simultaneously?

Yes, the OPA347PA supports true rail-to-rail input and output operation simultaneously. Its input common-mode range extends from (V–) – 0.2V to (V+) + 0.2V, and its output swings within 5mV of both rails into 100kΩ loads. This allows full-scale signal handling in single-supply configurations - for example, amplifying a 0–2.5V sensor output to drive a 0–2.5V ADC reference without clipping or level-shifting circuitry.

What is the maximum capacitive load the OPA347PA can drive in unity-gain configuration?

The OPA347PA can directly drive up to 250pF of pure capacitive load in unity-gain configuration while maintaining stability and <10% overshoot. For larger loads, TI recommends adding a 10Ω–20Ω series resistor at the output. This preserves DC accuracy for light resistive loads while eliminating ringing - a proven technique validated in the OPA347PA datasheet Figure 6 and typical characteristics.

Is the OPA347PA pin-compatible with other OPA347 variants like OPA347UA or OPA347NA?

No - the OPA347PA (DIP-8) is not pin-compatible with OPA347NA (SOT23-5) or OPA347UA (SO-8). While all share identical electrical functionality, their pinouts differ: OPA347PA uses pins 1–4 and 8 for Out, –In, +In, V–, and V+ with three NC pins; OPA347NA has 5 pins in SC70/SOT23 format; OPA347UA uses standard SO-8 pinout with no NC pins. Board layout must be redesigned when substituting packages.

What is the input bias current specification for the OPA347PA?

The OPA347PA has a typical input bias current of ±0.5pA and a maximum of ±10pA over temperature. This ultra-low value results from its CMOS input stage and enables high-impedance sensor interfacing - such as thermistors, pH electrodes, or photodiode transimpedance configurations - without significant DC error or drift. The OPA347PA maintains this spec across its full –55°C to +125°C operating range.