NXP's TFA9881 and TFA9882 are mono, filter-free class-D audio amplifiers in a 9-bump wafer level chip-size package (WLCSP) with a 400 μm pitch.

The digital input interface is an over-sampled pulse density modulated (PDM) bit stream. The TFA9881 receives audio and control settings via this interface. Dedicated silence patterns are used to configure the control settings of the device, such as mute, gain, pulse width modulated (PWM) output slope, clip control, and bandwidth extension (this control mechanism is not required if the default settings are used). The power-down to operating mode transition is triggered when a clock signal is detected.

The device features low RF susceptibility because it has a digital input interface that is insensitive to clock jitter. The second order closed loop architecture used in the TFA9881 provides excellent audio performance and high supply voltage ripple rejection.