STG3696E datasheet(9/21 Pages) STMICROELECTRONICS

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STG3696E

Operation

Doc ID 18165 Rev 2

9/21

Operation

5.1

Overvoltage fault protection

STG3696E features an overvoltage fault protection in compliance to USB fault protection

specification. The fault protection circuitry is triggered when the voltage on the COMn

channels raise above VOVDT. The overvoltage fault protection helps to protect the switch and

USB transceiver from being damaged by excessive voltage levels.

5.2

Negative charge pump for negative rail audio signaling

STG3696E uses a negative charge pump to generate a negative supply which allows the

audio signal to swing below ground (up to VCC – 5.0 V) on the AUn channels. If the device

fault protection is activated when the voltage on the COMn channels raise above VOVDT,

there must not be a negative voltage attached to the AUn channels.

5.3

VBUS detection feature

The connection between USBn and COMn is triggered when VBUS voltage is detected to be

higher than VBUSTHRES. If VBUS is constantly present in the application, driving the audio

override enable (AOVR) high will connect the AUn channels to the COMn channels. If AOVR

is low, the switching between AUn and USBn is controlled by the VBUS detection.

5.4

Pop noise suppression

When the AUn channels are not connected to the COMn channels, the AUn channels are

automatically connected to 200

Ω shunt resistors which helps to discharge any capacitance

built up on the AUn channels. This will reduce the possibility of pop and click noise

occurrence when switching between USB and audio sources.

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