ZHCSMU9A December 2020 – September 2021 TAS2764
PRODUCTION DATA
The device support post-filter feedback by closing the amplifier feedback loop after an external filter. The feedback is applied using the VSNS_N and VSNS_P terminals of the device. This feature can be disabled using the PFFB_EN register bit (if an external filter that violates the amplifier loop stability is implemented). When PFFB is disabled, the feedback will be internally routed from the OUT_N and OUT_P pins of the device.
In the PFFB mode of operation the following conditions have to be met: f0>10MHz and f0/Q>2.5MHz (f0 and Q are the cutoff frequency and the quality factor of the external filter).
When using PFFB with external LC filtering overshoot might occur at the speaker terminals. It is recommended to connect resistors (see Section 9.2) between speaker terninals and VSNS pins to protect internal diodes.