STMicroelectronics E-TDA7385

Overview

E-TDA7385 from STMicroelectronics is a 4-channel Class AB audio power amplifier in Flexiwatt25 package, delivering up to 42 W per channel into 4 Ω at 14.4 V supply, with integrated clipping detection, thermal shutdown, and fault diagnostics for output-to-GND/VS shorts. It serves as the main audio output stage in high-end automotive head units.

For engineers reviewing the E-TDA7385 datasheet, E-TDA7385 pinout, E-TDA7385 application, or E-TDA7385 equivalent, key selection criteria include its fixed 26 dB gain, rail-to-rail output swing without bootstrap capacitors, diagnostic open-collector output (pin 25), and compliance with automotive supply transients including load dump (50 V/50 ms) and reversed battery.

Technical Context

The TDA7385 uses a fully complementary PNP/NPN output stage enabling rail-to-rail voltage swing and eliminating external bootstrap capacitors. Its internal SVR (Supply Voltage Rejection) block biases all inputs and AC-GND (pin 16) at Vs/2, ensuring zero DC current through feedback networks and enabling high PSRR (65 dB typ. at 100 Hz).

Diagnostics are consolidated on a single open-collector output (pin 25), where pulsed current indicates clipping events, while sustained low-level sinking signals indicate thermal proximity, output shorts, or overtemperature. Clipping detection responds to absolute output power level-not frequency-making it effective across the full 20 Hz–75 kHz audio band.

Key Specifications

Pinout & Package

Package: Flexiwatt25 (ECOPACK®), vertically mounted with exposed metal tab (pin 1) for direct heatsink attachment and thermal conduction. Dimensions per Figure 19: 22.2 mm × 11.7 mm × 4.5 mm (L×W×H), 25-pin single-row layout.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar quad-channel automotive audio amplifier applications.

Compared with TDA7386, E-TDA7385 offers lower idle current and proven thermal robustness in passive-cooled head units; versus TPA5566DCA, it delivers superior THD+N (<0.04% vs. ~0.1%) and eliminates external filter components, simplifying compliance testing.

Availability

E-TDA7385 is available at Aetrix Electronics and suitable for automotive head units, aftermarket stereo receivers, multi-zone in-car entertainment systems, and infotainment display audio requiring stable component supply and long-term lifecycle support.

Supply support for E-TDA7385 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, designing and manufacturing microcontrollers, power ICs, sensors, and analog devices for automotive, industrial, and consumer markets.

The TDA7385 belongs to ST's automotive audio power amplifier product line, engineered specifically for high-fidelity, thermally robust, and fault-aware audio output in 12 V vehicle electrical environments.

FAQ

What is the maximum supply voltage the E-TDA7385 can withstand during load dump events?

The E-TDA7385 supports peak supply voltage up to 50 V for 50 ms per absolute maximum ratings (Table 2), making it compliant with ISO 7637-2 Load Dump Pulse 5a. This rating is achieved via integrated clamp circuitry and does not require external TVS diodes for basic protection in most automotive head unit designs.

How does the clipping detector on pin 25 differentiate between clipping and thermal fault conditions?

Pin 25 outputs short-duration current pulses synchronized to individual clipping events (Figure 16), whereas thermal faults produce sustained low-voltage states lasting seconds. Designers distinguish them using RC time-constant filtering: fast RC networks pass clipping pulses to microcontrollers for gain reduction, while slow integrators detect prolonged low states for thermal shutdown alerts.

Can the E-TDA7385 operate with a single-ended input configuration?

Yes - the E-TDA7385 accepts ground-referenced (single-ended) inputs on pins 5,6,21,22. Its internal SVR block biases each inverting input at Vs/2, allowing direct coupling via 0.1 µF capacitors. No differential input stage or external bias network is required, simplifying integration with standard preamp outputs.

What is the recommended minimum heatsink thermal resistance for continuous 4×42 W operation?

With R_{th j-case} = 1 °C/W and max T_j = 150 °C, ambient ≤ 70 °C, and case-to-heatsink interface resistance ≤ 0.5 °C/W, the heatsink must provide ≤ 1.5 °C/W total thermal resistance to maintain safe junction temperature. ST recommends aluminum extrusion heatsinks ≥ 200 cm² surface area with forced airflow for full-power duty cycles.