Texas Instruments OPA1632D

Overview

OPA1632D from Texas Instruments is a fully differential audio operational amplifier designed for high-fidelity signal conditioning in professional audio systems. It delivers 1.8 MHz large-signal bandwidth, 72 V/μs slew rate, 1.25 nV/√Hz input voltage noise, and 0.000028% THD+N at 1 kHz with 2 kΩ load - enabling ultra-low-distortion single-ended-to-differential conversion for ADC driving and Class-D predriver applications.

For engineers reviewing the OPA1632D datasheet, OPA1632D pinout, OPA1632D application, or OPA1632D equivalent, key selection criteria include differential output common-mode control (VOCM), shutdown enable timing (2 μs turn-on/off), thermal performance in SO-8 (RθJA = 126.3°C/W), and verified operation across ±2.5 V to ±15 V dual supplies.

Technical Context

The OPA1632D implements a fully differential architecture with independent input and output stages, supporting both differential-input/differential-output and single-ended-input/differential-output configurations. Its VOCM pin provides precise control of output common-mode voltage, critical for matching ADC input ranges and minimizing DC offset errors in precision audio chains.

Internally, it features matched gain blocks, low-impedance output buffers, and an active shutdown circuit referenced to V−. The enable threshold is (V−) + 1.45 V (active high), with internal 250-kΩ pull-up ensuring default-enable behavior when unconnected - eliminating need for external biasing in most designs.

Key Specifications

Pinout & Package

OPA1632D is packaged in an 8-pin SOIC (D package), 4.9 mm × 6 mm body size, with standard lead pitch and creepage. Thermal performance is characterized at RθJA = 126.3°C/W, requiring moderate PCB copper area for continuous 13 mA operation at ambient temperatures up to +85°C.

Key Features

Applications

Equivalent & Alternatives

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

Compared with AD8138ARZ and THS4561IRGET, the OPA1632D uniquely combines SO-8 compatibility, integrated shutdown, VOCM control, and 1.25 nV/√Hz noise - making it optimal for space-constrained, power-aware professional audio systems requiring plug-and-play differential interface capability.

Availability

OPA1632D is available at Aetrix Electronics and suitable for professional audio mixer input stages, high-resolution audio ADC drivers, and Class-D amplifier predrivers requiring stable component supply, long-term lifecycle support, and traceable sourcing for industrial and broadcast equipment manufacturing.

Supply support for OPA1632D 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 design and manufacturing.

The OPA1632D belongs to TI's OPA high-fidelity audio op-amp family, engineered specifically for professional audio infrastructure where ultra-low noise, ultra-low distortion, and robust differential signaling are non-negotiable design requirements.

FAQ

What is the maximum large-signal bandwidth specification for OPA1632D?

The OPA1632D has a typical large-signal bandwidth of 1.8 MHz at G = +2 and VO = 20 VPP, as confirmed in Revision E (August 2023) of the official datasheet. This value reflects improved performance over earlier revisions and enables faithful reproduction of high-amplitude audio transients up to 200 kHz without slew limiting. The OPA1632D maintains this bandwidth under ±15 V supply conditions with appropriate load and feedback network design.

Does OPA1632D support single-ended input to differential output conversion?

Yes, the OPA1632D natively supports single-ended input to differential output conversion using VIN+ as the signal input and VIN− tied to a reference (e.g., VOCM or ground). Its fully differential architecture and VOCM pin allow precise control of output common-mode voltage - essential for direct interfacing with differential-input ADCs like the PCM1804 without external level-shifting circuitry. This configuration is explicitly validated in the datasheet's Figure 7-2.

What is the shutdown behavior of OPA1632D when the Enable pin is left unconnected?

When the Enable pin (Pin 7) of the OPA1632D is left unconnected, its internal 250-kΩ pull-up resistor to V+ ensures the device remains enabled by default. The enable threshold is (V−) + 1.45 V, so with typical dual-supply operation (e.g., ±15 V), the floating pin sits well above this threshold. This eliminates the need for external pull-up resistors in most applications, simplifying layout and improving reliability in professional audio equipment.

Can OPA1632D operate from a single 5-V supply?

No, the OPA1632D is specified only for dual-supply operation from ±2.5 V to ±15 V, as stated in Section 6.3 Recommended Operating Conditions. Single-supply operation is not supported - the absolute maximum ratings and electrical characteristics assume symmetrical positive and negative rails. Attempting single-supply use violates the recommended operating conditions and may result in degraded performance or damage due to input common-mode or output swing limitations.

How does the VOCM pin affect OPA1632D's output common-mode voltage?

The VOCM pin directly sets the average voltage of VOUT+ and VOUT−, establishing the output common-mode level. For example, applying 2.5 V to VOCM forces the midpoint of the differential output pair to 2.5 V - matching the reference voltage of many audio ADCs (e.g., PCM1804). This eliminates the need for AC-coupling capacitors and associated low-frequency phase distortion, preserving full-bandwidth signal integrity in high-fidelity audio paths.