A 22-kHz tone detector is implemented in the TPS65235 solution. The detector extracts the AC coupled tone signal from the DIN input and provides it as an open-drain signal on the DOUT pin. With bit DOUTMODE default setting of the Control Register 2, if tone is present, the DOUT output is logic low; if tone is not present, the internal output FET is off. If a pull high resistor is connected to the DOUT pin, the output is logic high. The maximum tone out delay with respect to the input is one and half tone cycle.

Bit DOUTMODE of Control Register 2 is reserved and should not be used.