TDA7851

Overview

The TDA7851 is a Class-AB audio power amplifier utilizing MOSFET technology, designed for high-power car radio applications. It features a quad bridge configuration with four channels. The device delivers up to 4 x 50 W output power. It operates within a supply voltage range of 8 V to 18 V and supports load impedances of 2 Ohms or 4 Ohms. The amplifier incorporates a fully complementary P-Channel/N-Channel output structure for rail-to-rail swing. Key electrical parameters include a THD+N of 0.01% and a quiescent current of 150 mA. It is housed in a 25-Flexiwatt package suitable for through-hole mounting.

Feature Summary

• Breakthrough MOSFET technology enabling high output power with minimized saturation losses
• Fully complementary P-Channel/N-Channel output structure allowing rail-to-rail output voltage swing
• Excellent driving capability for low impedance loads down to 2 Ohms
• Low external component count due to internally fixed gain and absence of bootstrap capacitors

Applications

• High-power car radio systems
• Automotive audio amplification
• In-vehicle infotainment sound processing

Procurement Notes

Verify the specific suffix variant (e.g., A, L, F) required for your design, as packaging and thermal characteristics may differ. Confirm AEC-Q100 qualification status if automotive reliability is mandatory. Ensure the Flexiwatt package type matches your PCB footprint requirements. Check datasheet revisions for any updates to protection features or pin configurations before finalizing procurement.

Selection Notes

Select this component when high efficiency and low distortion are critical for automotive audio. The internal fixed gain simplifies circuit design by removing the need for external compensation networks. Consider the thermal management capabilities of the Flexiwatt package for high-power continuous operation. Verify compatibility with vehicle electrical systems operating between 8 V and 18 V.

Part Context

This part belongs to STMicroelectronics' portfolio of Class-AB audio power amplifiers tailored for automotive use. It complements other models like the TDA7388 and TDA7851L within the same functional family. These devices are engineered to meet the stringent demands of modern vehicle infotainment systems, offering robust performance in challenging electrical environments.

Replacement Considerations

TDA7851L: Similar MOSFET quad bridge amplifier with comparable power output and application scope. TDA7851A: Variant with potentially different packaging or thermal specifications. Verify pinout compatibility and thermal resistance values before substitution.