STMicroelectronics TDA7391PDU

Overview

TDA7391PDU from STMicroelectronics is a 32 W bridge-type Class AB audio power amplifier in PowerSO20 (slug-up) package, designed for high-power car radio applications. It delivers 32 W into 3.2 Ω at 14.4 V with 10% THD, features differential/single-ended inputs, fixed 30 dB gain, and integrated clipping detection. Used in automotive head units as main output stage driving 4 Ω or 3.2 Ω speakers.

For engineers reviewing the TDA7391PDU datasheet, TDA7391PDU pinout, TDA7391PDU application, or TDA7391PDU equivalent, key selection criteria include thermal resistance (2 °C/W), standby current (<100 µA), mute/standby timing programmability, short-circuit protection to GND/VS/load, and rail-to-rail bridge output swing without bootstrap capacitors.

Technical Context

The TDA7391PDU implements a fully complementary PNP/NPN bridge output stage enabling 32 W into low-impedance 3.2 Ω loads while maintaining thermal stability via internal overtemperature shutdown at 160 °C. Its differential input architecture supports both single-ended and balanced signal sources with 65 dB CMRR at 1 kHz and 60 kΩ typical input impedance.

Protection circuitry includes short-circuit detection across load terminals, to supply (VS), to ground (GND), open-GND fault handling, load-dump tolerance up to 50 V peak, and ESD robustness. The on-chip clipping detector (CD pin) asserts low during ≥10% THD, enabling external gain compression control.

Key Specifications

Pinout & Package

Package: PowerSO20 (slug-up) - thermally enhanced 20-pin surface-mount package with exposed metal slug on top side for direct PCB copper thermal coupling.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TDA7391PDU, TDA7388 offers greater channel count and output power but increases component count and layout sensitivity, while STA559BW shifts to digital domain and eliminates analog protection features like CD pin and analog mute control-making TDA7391PDU optimal for cost-sensitive, analog-input, thermally constrained mono/bridge automotive amplifiers.

Availability

TDA7391PDU is available at Aetrix Electronics and suitable for car radio head units, aftermarket audio boosters, infotainment reference designs, and compact audio evaluation platforms requiring stable component supply and automotive-grade thermal reliability.

Supply support for TDA7391PDU 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

STMicroelectronics is a global semiconductor leader headquartered in Geneva, Switzerland, specializing in automotive, industrial, and power management ICs with broad manufacturing and qualification capabilities.

The TDA7391PDU belongs to ST's automotive audio power amplifier product line, engineered specifically for high-fidelity, thermally robust Class AB bridge operation in space-constrained car radio applications where analog interface simplicity and protection integrity are critical.

FAQ

What is the maximum safe operating supply voltage for TDA7391PDU?

The absolute maximum DC supply voltage is 28 V, but the recommended operating range is 8–18 V per datasheet Section 3.3. Operation above 18 V risks exceeding thermal limits under load, while below 8 V causes output power collapse and potential instability. Load-dump transients up to 50 V (50 ms) are tolerated due to integrated protection.

How does the clipping detector (CD pin) function in practical circuit design?

The CD pin is an open-collector output that pulls low when output distortion reaches or exceeds 10% THD. In practice, it drives an external LED for visual clipping indication or connects to a comparator input to trigger analog gain reduction. No pull-up resistor is needed if interfacing directly with a microcontroller GPIO configured with internal pull-up.

Can TDA7391PDU operate with a single-ended input signal?

Yes - the input stage accepts single-ended signals by capacitively coupling the signal to the non-inverting input (pin 14 or 15) while tying the inverting input to signal ground (pin 12) through matched impedance. Input impedance remains 30–55 kΩ, and CMRR degrades slightly versus true differential mode but stays >50 dB across audio band.

What thermal design considerations apply to the PowerSO20 (slug-up) package?

The slug-up orientation requires mounting the exposed metal pad to a large copper area on the top PCB layer, thermally connected via multiple vias to inner-layer ground planes. With Rth j-case = 2 °C/W, achieving ≤85 °C case temperature at 32 W output demands ≥25 cm² of 2-oz copper on top layer plus ≥4 thermal vias (0.3 mm diameter) to internal ground planes.