TS3A27518E: Power sequencing

Hi Naseef,

Although this switch does offer powered off protection, it is only valid when Vcc = 0 (see more details here)

The TS3A27518E  does not support Fail-Safe logic (Ensures the switch stays off and the voltage on the logic pin and does not back-power Vcc voltage on control pin is greater than Vcc). See more details in  TI Precision Labs - Switches and muxes: What is fail-safe logic?

If a ramp rate difference causes a condition where NC or COM > Vcc, there could be current and that should be limited according to the ABS max table.

Hi  Saminah,

Thanks for your reply.

NC and COM QSPI devices use same supply voltage VCC_VU_1V8(VCC). Pin IN1 and IN2 pulldown to GND (Default). QSPI Connected to NO will up only after some times of VCC_VU_1V8, that is driven by another IO voltage.The IN1 and IN2 pins are driven high only after NC interface power up. Will this configuration cause any issue ?

Hi Naseef,

Thanks for sharing the schematic. It looks ok.

Since the VCC , NC , COM are using same supply, just caution towards the details I shared above to limit the current according to Abs max table (using a series resistor can help achieve that).

Thanks

Saminah

Hi Saminah, 

Thanks for your reply.

If I power in the order

1.VCC first then, 

2.NC , COM - simultaneous , then

3.NO

Is this power sequence cause any problems ?