7.4.1 S3 and Pseudo-S5 Support

The TPS51200-Q1 device provides S3 support by an EN function. The EN pin can be connected to an SLP_S3 signal in the end application. Both the REFOUT and VO pin are on when EN = high (S0 state). The REFOUT pin is maintained while the VO pin is turned off and discharged through an internal discharge MOSFET when EN = low (S3 state). When EN = low and the REFIN voltage is less than 0.390 V, the TPS51200-Q1 device enters pseudo-S5 state. Both the VO and REFOUT outputs are turned off and discharged to the GND pin through internal MOSFETs when pseudo-S5 support is engaged (S4/S5 state). Figure 19 shows a typical startup and shutdown timing diagram for an application that uses S3 and pseudo-S5 support. It is also allowed to turn on VLDOIN earlier than VIN during power on, and turn off VIN earlier than VLDOIN during power off.