Automotive class-G audio amplifier delivers high-definition sound
The TDA7901 automotive audio amplifier from STMicroelectronics integrates a buck controller for class-G power switching and supports high-definition audio, a market-unique combination for great listening and high efficiency. A single-chip quad-bridge amplifier in advanced BCD technology, the TDA7901 integrates a full D/A converter, digital input for direct connection to I2S (or TDM) and powerful MOSFET output stages. The integrated D/A converter allows the performance to reach an outstanding 117 dB S/N ratio with more than 117 dB of dynamic range.
In class-G operation, the TDA7901 buck controller automatically optimizes the voltage supplied to the bridge-tied load (BTL) power stage depending on the audio-signal level. The resulting smooth, analog sound comes with near-class-D efficiency at normal listening levels. Because the power dissipation is much lower compared with a conventional class-A/B amplifier, the heatsink requirement is optimized. Integrating the buck controller in the IC contributes to reducing system size and weight. The audio amplifier also cuts the bill of materials, simplifies circuit design, and saves developing firmware to control the voltage rail.
The TDA7901 is suited to use in many in-vehicle information (IVI) systems, such as head units, smart cockpit systems, external amplifiers, and more. The amplifier signals full in-play diagnostics including real-time load-current monitoring through I2S or I2C interfaces, enabling ASIL-A certification of safety-related applications like warning-tone generators and acoustic vehicle alerting systems (AVAS). A digital impedance meter is also provided, ensuring systems containing the TDA7901 audio amplifier can meet the most demanding requirements of automotive OEMs.
With its I2S digital input and intelligent quad-BTL output, the TDA7901 audio amplifier delivers 4x 43-W of audio power (at 4 Ω load, saturated output at 14.4 V). The amplifier has 80 kHz bandwidth to handle high-definition audio. Its wide supply-voltage range, spanning 4.5 V to 18.5 V, prevents disruption by start-stop engine operation and general automotive electrical transients.
The TDA7901 audio amplifier is due to enter production in the second half of 2022, in a Power-SO36 package.
