Audio reference design eschews heatsink

The IRAUDAMP3 Class D audio reference design from International Rectifier features the IRS20124S high-voltage analog IC and IRF6645 DirectFET power MOSFETs. The MOSFETs complete a six-channel, 120W, half-bridge, Class D audio power amplifier with no heatsink.

The IRS20124S high-voltage IC used in this reference design has an internal selectable dead-time generation circuit. It's immune to noise and supply voltage fluctuations to help achieve a total harmonic distortion (THD) of 0.01% at 60W and 4Ω, and 94% efficiency at 120W and 4Ω single channel.

The IC also contains integral bidirectional current sensing and an integrated shutdown function. These features protect the output MOSFETs when an overcurrent condition occurs, such as a short-circuited speaker wire.

The IRAUDAMP3, which has a footprint of 29.03cm² (4.5 in.²) for each two-channel control and switch function, also uses IRF6645 DirectFET power MOSFETs. The DirectFET packaging technology enhances performance in Class D audio amplifier circuits by reducing lead inductance to improve switching performance and reduce EMI noise.