Texas Instruments OPA1679IDR

Overview

OPA1679IDR from Texas Instruments is a quad-channel, low-noise, low-distortion audio operational amplifier in a 14-pin SOIC package. It delivers 4.5 nV/√Hz input voltage noise, 0.0001% THD+N at 1 kHz, rail-to-rail output swing within 800 mV of rails (2-kΩ load), 16 MHz gain bandwidth, and operates from ±2.25 V to ±18 V or 4.5 V to 36 V - enabling high-fidelity signal conditioning in professional audio mixer front-ends and A/V receiver line-stage circuits.

For engineers reviewing the OPA1679IDR datasheet, OPA1679IDR pinout, OPA1679IDR application, or OPA1679IDR equivalent, this page provides verified specifications, SOIC-14 terminal mapping, real-world audio use cases, and two validated alternative parts with documented functional and application-level differences - all grounded in TI's SBOS855E production data sheet (Rev. E, Dec 2022).

Technical Context

The OPA1679IDR implements a folded-cascode input stage paired with a Class AB rail-to-rail output stage, achieving unity-gain stability without external compensation. Its independent channel architecture eliminates crosstalk (<–130 dB at 1 kHz) and prevents inter-channel interaction during overload - critical for multi-channel audio routing and summing applications.

Phase-reversal protection ensures output remains bounded at the supply rail when inputs exceed common-mode range (V_CM = (V⁻) + 0.5 V to (V⁺) − 2 V), avoiding catastrophic signal inversion in non-inverting configurations. Input bias current remains ultra-low (±10 pA typ.) across –40°C to +125°C, supporting precision DC-coupled microphone preamp designs.

Key Specifications

Pinout & Package

OPA1679IDR is supplied in a 14-pin SOIC (D package) with standard JEDEC outline, 1.27 mm pitch, and exposed pad not present (unlike QFN variant). Pin 1 is top-left corner marker; device orientation follows TI's standard SOIC top-view convention.

Key Features

Applications

Equivalent & Alternatives

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

Compared with OPA1679IDR, the OPA1679IPW reduces board area by 30% and improves thermal resistance by 30%, while OPA1679IRUM cuts thermal resistance by 57% and adds mechanical robustness for vibration-prone environments - all without altering circuit design or performance targets.

Availability

OPA1679IDR is available at Aetrix Electronics and suitable for professional audio mixer front-ends, guitar amplifier preamp stages, A/V receiver line-level buffering, and automotive external amplifier signal conditioning requiring stable component supply, long-term lifecycle support, and TI-authorized traceability.

Supply support for OPA1679IDR 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 high-performance audio signal chain components.

The OPA167x family was designed specifically for professional and high-end consumer audio applications demanding ultra-low noise, vanishingly low distortion, and exceptional channel isolation - targeting microphone preamplifiers, mixing consoles, and studio monitors.

FAQ

What is the maximum capacitive load the OPA1679IDR can drive stably?

The OPA1679IDR maintains stability with up to 100 pF capacitive load in unity-gain configuration, as confirmed by phase margin >60° and <10% overshoot in Figure 6-25 and Figure 6-26 of the SBOS855E datasheet. Driving larger loads requires isolation resistor (≥10 Ω) in series with the output to preserve stability - a technique validated for OPA1679IDR in TI's application notes on capacitive load driving.

Does the OPA1679IDR support single-supply operation?

Yes, the OPA1679IDR supports true single-supply operation from 4.5 V to 36 V, with rail-to-rail output swing and input common-mode range extending to within 0.5 V of V⁻. Its input stage functions correctly with V⁻ tied to ground, enabling use in 5 V or 3.3 V systems - provided input signals remain within the specified V_CM limits and output load is appropriately biased.

What is the thermal resistance (R_θJA) of the OPA1679IDR in SOIC-14 package?

The junction-to-ambient thermal resistance (R_θJA) for OPA1679IDR in SOIC-14 (D) package is 90°C/W, as specified in Section 6.6 of the SBOS855E datasheet. This value assumes standard JEDEC 2-layer board layout (2 oz copper, 1 in² copper pour under package); actual thermal performance improves with enhanced PCB copper area and airflow.

How does the OPA1679IDR handle input overvoltage beyond its common-mode range?

The OPA1679IDR incorporates phase-reversal protection that clamps the output at the nearest supply rail instead of inverting polarity when inputs exceed V⁻ + 0.5 V or V⁺ − 2 V. This behavior - demonstrated in Figure 7-1 of SBOS855E - prevents destructive signal corruption in non-inverting configurations during transient overdrive events.

Is the OPA1679IDR pin-compatible with other OPA167x variants?

No - OPA1679IDR (SOIC-14) is not pin-compatible with OPA1679IPW (TSSOP-14) or OPA1679IRUM (QFN-16), despite identical electrical functionality. Pin counts and layouts differ: SOIC-14 and TSSOP-14 share 14-pin count but differ in pitch and thermal pad presence, while QFN-16 adds two NC pins and shifts all terminals. PCB redesign is required for package substitution.