Texas Instruments OPA2705PA

Overview

OPA2705PA from Texas Instruments is a dual, rail-to-rail input/output CMOS operational amplifier optimized for low-power, precision signal conditioning in single- or dual-supply systems. It delivers 1MHz gain-bandwidth, 0.6V/µs slew rate, ±0.5mV input offset voltage, 160µA quiescent current per amplifier, and operates from ±2V to ±6V (or 4V–12V single supply), targeting sensor interfaces and portable data acquisition.

For engineers reviewing the OPA2705PA datasheet, OPA2705PA pinout, OPA2705PA application, or OPA2705PA equivalent, key selection considerations include its rail-to-rail I/O swing (within 40mV of rails at light load), ultra-low input bias current (1pA), limited-range CMRR (96dB), unity-gain stability, and DIP-8 package compatibility with legacy through-hole prototyping and industrial control boards.

Technical Context

The OPA2705PA employs a complementary differential input stage enabling rail-to-rail common-mode input range extending 300mV beyond both supply rails, with a 500mV transition region where both N- and P-channel pairs conduct-causing minor parameter variation in PSRR, CMRR, and THD. Its class AB output stage supports rail-to-rail output swing down to 40mV from V+ or V− under 100kΩ load.

This dual op amp is unity-gain stable and specified over –40°C to +85°C. It drives capacitive loads up to 1000pF, with enhanced stability at higher gains; a 10Ω–20Ω series resistor in the feedback path improves unity-gain step response with large capacitive loads while preserving DC accuracy.

Key Specifications

Pinout & Package

OPA2705PA uses an 8-pin plastic dual in-line package (PDIP-8) with 0.3-inch body width, compatible with standard through-hole PCB footprints and breadboard prototyping. Thermal resistance θ_JA is 100°C/W.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar dual rail-to-rail op amp applications.

Compared with TLV2462CP and MCP6022-I/P, the OPA2705PA uniquely balances ultra-low power (160µA), rail-to-rail input beyond supplies, and extended temperature/voltage rating-making it the only option among the three qualified for automotive sensor signal chains operating from ±5V at –40°C.

Availability

OPA2705PA is available at Aetrix Electronics and suitable for automotive sensor interfaces, portable data acquisition systems, and active filter designs requiring stable component supply across extended temperature ranges and legacy through-hole assembly.

Supply support for OPA2705PA 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 OPA705 family-including OPA2705PA-is designed for cost-sensitive, low-power applications demanding rail-to-rail I/O, high input impedance, and robust operation across industrial and automotive environments.

FAQ

What is the maximum supply voltage for the OPA2705PA?

The OPA2705PA has an absolute maximum supply voltage of 13.2V across V+ and V− terminals. Its recommended operating range is ±2V to ±6V (dual supply) or 4V to 12V (single supply), with full electrical specifications guaranteed from ±2V to ±6V over –40°C to +85°C. Exceeding 13.2V risks permanent damage per TI's Absolute Maximum Ratings.

Does the OPA2705PA support rail-to-rail input beyond the supply rails?

Yes, the OPA2705PA supports rail-to-rail input with common-mode voltage range extending 300mV beyond both V+ and V− rails at room temperature. This is enabled by its complementary N- and P-channel input stage. However, parameters like CMRR and PSRR degrade within the 500mV transition region near the rails, as documented in the SBOS182A datasheet.

Can the OPA2705PA drive capacitive loads, and what is the limit?

The OPA2705PA can drive up to 1000pF of pure capacitive load while maintaining stability. Its ability to drive larger capacitive loads improves with increased closed-loop gain. For unity-gain configurations with >100pF loads, adding a 10Ω–20Ω resistor in series with the output inside the feedback loop reduces ringing and improves step response without affecting DC accuracy.

What is the input bias current specification for the OPA2705PA?

The OPA2705PA features an input bias current of ±1pA (typical) at +25°C, with a maximum of ±10pA over temperature. This ultra-low value results from its CMOS input stage and makes the device ideal for interfacing with high-impedance sources such as photodiodes, pH electrodes, and piezoelectric transducers where leakage-induced errors must be minimized.

Is the OPA2705PA unity-gain stable, and what does that mean for circuit design?

Yes, the OPA2705PA is unity-gain stable, meaning it remains stable when configured as a voltage follower (gain = +1) without requiring external compensation components. This simplifies design in applications like transducer buffering and reference voltage followers, eliminating risk of oscillation and reducing bill-of-materials count compared to decompensated op amps.