TPS25750: Necessity of PP5V in a sink role

Jonathan Lui

Part Number: TPS25750

Hi,

We are using the TPS25750D in a sink-only role. My understanding is that the internal logic powers off of VIN_3V3 (and the resulting LDO_3V3 & LDO_1V5) so I am wondering if PP5V can be left unconnected since we are not providing power as a source. Please let me know if PP5V is necessary or not in a sink-only role.

Thanks,
Jonathan

over 4 years ago

0 Chuck Branch over 4 years ago

TI__Mastermind 32661 points

Jonathan,

PP5V and VIN3V3 are not necessary in the Sink only role.

This FAQ describes how to configure the TPS25750D for this mode: https://e2e.ti.com/f/1/t/988215

0 Jonathan Lui over 4 years ago in reply to Chuck Branch

Prodigy 40 points

Thanks for the reply. No PP5V makes sense to me. However, in the datasheet, it states that VIN3V3 is not necessary only in dead-battery mode. Our sink configuration is for 20V. Is dead-battery mode limited to 5V? Or can I switch from 5V to 20V sink profile while in dead-battery mode? Thanks for the confirmation.

+1 Chuck Branch over 4 years ago in reply to Jonathan Lui

TI__Mastermind 32661 points

Jonathan,

The VIN3V3 is not required for sink applications. The TPS25750 will start up in dead battery mode and then will negotiate to your target Voltage/Current Range.

0 Jonathan Lui over 4 years ago in reply to Chuck Branch

Prodigy 40 points

Thanks Chunk. Since I don't need VIN3V3 nor PP5V, I am assuming I don't need the recommended capacitor for those pins either? Please let me know if there is some internal circuitry that still prefers having decoupling caps at those pins.

+1 Chuck Branch over 4 years ago in reply to Jonathan Lui

TI__Mastermind 32661 points

The capacitor on the VIN_3V3 is necessary. The pp5V cap is not

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TPS25750: Necessity of PP5V in a sink role