TPS2373: What if VC_IN is always there, would it cause any issue?

Cage Chen

Part Number: TPS2373
Other Parts Discussed in Thread: TPS2372

Hi,

I got a question from customer asking about what if VC_IN is always there, would it cause any issue?

Before RJ45 connecting, VC_IN is there, are there any possible leakages happen?

Thank you.

Best regards, Cage.

ps, VC_IN=12V and could be always there. Or can customer just remove the 12V for VC_IN? left VC_IN floating?

VDD comes from RJ45 connecting.

Customer doesn't need advanced startup feature, but they have used TPS2373 for a long time, and they don't want to change to TPS2372.

0 Thomas Amlee over 6 years ago

Hi Cage,

VC_IN needs to be kept above UVLO if a bias winding is not used. See our FAQ for a circuit example: e2e.ti.com/.../769359

There is ~0.8mA of max leakage current into VC_IN to account for.

Thanks,
Tom Amlee
PoE PD Apps Engineer

0 Cage Chen over 6 years ago in reply to Thomas Amlee

Hi Tom,

Thanks a lot for your answer.

What if VC_IN comes before VDD, will it cause any issue?

Or we can just apply a voltage higher than 8.5V on VC_IN.

Best regards, Cage.

0 Thomas Amlee over 6 years ago in reply to Cage Chen

Hi Chen,

From our testing, having a voltage at VC_IN before VDD is fine.

Thanks,
Tom Amlee
PoE PD Apps Engineer

0 Cage Chen over 6 years ago in reply to Thomas Amlee

Hi Tom,

Thanks a lot for your great help.

Best regards, Cage.

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