Intersil’s ISL99201 in 9-bump 0.4mm pitch WCSP is its smallest Class D amplifier.

It is a filterless, mono amplifier capable of delivering up to 2.5W into a 4ohm load.

It features a low-noise modulation scheme, operating with 86 percent efficiency at 400mW into 8 ohms, and has a signal-to-noise ratio (SNR) that is better than 95dB.

There is also a micropower shutdown mode with a typical shutdown current of 200nA. The fully-differential input of the ISL99201 provides 75dB rejection to common mode noise on the input. 

The amplifier is available in three fixed-gain settings and it is also available in an 8-lead TDFN package.

A companion device is the ISL99202 stereo capfree headphone amplifier which supports 16ohm to 600ohm speaker impedance.