Texas Instruments OPA725AID

Overview

OPA725AID from Texas Instruments is a single, rail-to-rail output, 20MHz gain-bandwidth precision CMOS operational amplifier optimized for driving 16-bit ADCs such as the ADS8342. It delivers 30V/µs slew rate, 6nV/√Hz input voltage noise at 100kHz, 0.0003% THD+N at 1kHz, and operates from ±2V to ±6V or +4V to +12V supplies. Its key role is high-fidelity signal buffering in optical networking transimpedance amplifiers and active filter stages.

For engineers reviewing the OPA725AID datasheet, OPA725AID pinout, OPA725AID application, or OPA725AID equivalent, this page provides verified technical context, SO-8 package pin mapping, real-world settling performance into ADC inputs, low-noise design trade-offs for photodiode interfaces, and validated alternative op amps for 16-bit data acquisition systems.

Technical Context

The OPA725AID uses a proprietary 12V analog CMOS process with a class AB output stage enabling rail-to-rail swing within 150mV of rails under light loads (100kΩ), while maintaining >110dB open-loop gain. Its 20MHz GBW and 30V/µs slew rate support fast 16-bit settling (450ns to 0.01%) into capacitive ADC inputs.

Input common-mode range extends from V− to (V+) − 2V, with CMRR ≥94dB over that full range at 25°C; PSRR exceeds 100dB at DC and remains >70dB up to 1MHz. Bias current is <200pA, enabling stable transimpedance operation with photodiodes without significant offset drift.

Key Specifications

Pinout & Package

OPA725AID is packaged in an 8-pin SOIC (SO-8, package code D), RoHS-compliant, with moisture sensitivity level MSL-2-260°C-1 year. Pin 1 is marked by a beveled corner or dot; device operates from −40°C to +125°C.

Key Features

Applications

Equivalent & Alternatives

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

Compared with OPA2725AID, the OPA725AID saves board space in single-amplifier roles and eliminates channel-to-channel crosstalk concerns; versus OPA743UA, it trades higher quiescent current for 3× bandwidth and 5× lower noise-critical for photodiode and fast-ADC use cases.

Availability

OPA725AID is available at Aetrix Electronics and suitable for optical transimpedance amplifiers, 16-bit ADC buffering, active filter design, and portable audio line driving requiring stable component supply across industrial temperature ranges.

Supply support for OPA725AID 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 data converters.

The OPA725AID belongs to TI's high-speed precision CMOS op amp product line, designed specifically for demanding signal-chain applications including optical networking, test equipment, and high-resolution data acquisition.

FAQ

What is the maximum capacitive load the OPA725AID can drive stably in unity-gain configuration?

The OPA725AID is unity-gain stable but exhibits increasing overshoot with capacitive loads >20pF. For CL = 20pF, small-signal overshoot is <10%; for CL = 100pF, overshoot reaches ~60%. To maintain stability with larger loads, insert a 10Ω–20Ω series resistor inside the feedback loop. This technique preserves DC accuracy while damping ringing-verified in TI's SBOS278B datasheet Figure 3. The OPA725AID's ability to drive capacitive loads is gain-dependent, improving at higher closed-loop gains.

Does the OPA725AID support true single-supply operation with input referenced to ground?

Yes, the OPA725AID supports true single-supply operation with its input common-mode voltage range extending down to V− (ground in single-supply mode) and up to (V+) − 2V. Its rail-to-rail output swings to within 150mV of either rail, enabling GND-referenced sensor interfaces and output stages without level-shifting. Input bias current remains <200pA at VCM = 0V, ensuring minimal offset error in single-supply transducer amplifiers.

How does the OPA725AID's 0.0003% THD+N compare to typical audio op amps?

The OPA725AID's 0.0003% THD+N at 1kHz and 2Vrms into 600Ω exceeds the performance of most general-purpose audio op amps (e.g., NE5532: ~0.0005%, LM4562: ~0.00003%). While LM4562 achieves lower distortion, the OPA725AID uniquely combines this low THD+N with 20MHz GBW and 30V/µs slew rate-making it suitable for wideband audio line drivers where both fidelity and transient response matter, unlike slower ultra-low-distortion parts.

Can the OPA725AID replace the OPA726AID in existing designs?

No-the OPA725AID lacks shutdown functionality and has no Enable or DGND pins. The OPA726AID includes dedicated enable logic referenced to DGND, reducing quiescent current to 6µA in shutdown mode. Swapping OPA725AID into an OPA726AID footprint would leave pins 1 and 4 (Enable and DGND) unconnected, causing undefined behavior or failure to power up. Use OPA725AID only in non-shutdown designs; for shutdown capability, select OPA726AID or redesign the enable interface.

What thermal considerations apply to the OPA725AID in SO-8 package at maximum supply voltage?

In SO-8 package, the OPA725AID has θJA = 150°C/W. At VS = +12V and IQ = 5.5mA, power dissipation is ~66mW. Under still-air conditions, this yields ~10°C junction-to-ambient rise-well within the −40°C to +125°C operating range. However, in enclosed enclosures or high ambient temperatures (>85°C), derating is advised. TI specifies maximum junction temperature as +150°C; sustained operation above +125°C ambient requires forced airflow or thermal vias under the exposed pad (not present in standard SO-8).