Filterless Class-D amplifier saves space and power for portable audio

Designers can implement a Class-D amplifier in a footprint of 4mm x 4mm, with minimal external components, using the SA58670A from NXP Semiconductors.

The SA58670A stereo amplifier is designed for filterless operation, and delivers up to 2.1W per channel into a 4Ω load when driven at 5.0V. Two external Gain-select pins support preset gain values of 6dB, 12dB, 18dB and 24dB, allowing direct volume control via host-processor outputs.

The small footprint of the SA58670A saves space in handheld applications, while internal thermal-shutdown and short-circuit protection also help designers save overall PCB space.

High performance in battery-powered applications is assured thanks to low current-draw in operating and shutdown modes, as well as high operating efficiency. The SA58670A achieves up to 74% efficiency when driving a 4Ω load and up to 88% when driving 8Ω. In addition, a 3.5ms start-up time maximises energy utilisation for longer battery lifetime.

Further advantages include high Power Supply Rejection Ratio (PSRR) and differential circuit topology for high noise immunity.

 

FEATURES Supply-voltage range: 2.5V to 5.5V 0.14% distortion at 1.0W Independent shutdown control for each channel Leadless HVQFN-20 package

APPLICATIONS Portable media players USB speakers Notebook PCs Cellular handsets

 

 

NXP Semiconductors / SA58670A