TPS23754: IT2P SPEC

Julian Chen

Expert 2550 points

Part Number: TPS23754

Dear TI E2E Member,

I see the IT2P minimum is 2mA.

But in dataaheet P.33, the finally calculate value is 0.625mA

Is it OK for this design? Does The minimum valus need to 2mA for IT2P?

over 7 years ago

0 Darwin Fernandez over 7 years ago

TI__Mastermind 41790 points

Hi Julian,

The ON spec is really showing the RDSon characteristic of the T2P internal FET (Very low). So operating at a lower current like shown is okay. Since this is a logic signal, the key design consideration is that the opto output goes LOW enough such that the load can recognize that a Type 2 PSE is connected.

Or you can look at the TPS23754EVM-420 below and see how its implemented. You can measure TP4 performance.

0 Julian Chen over 7 years ago in reply to Darwin Fernandez

Expert 2550 points

Dear Darwin,

Thanks for your reply.

So, does your means that RDSon maximum = 1/2mA(min)=500R?

0 Darwin Fernandez over 7 years ago in reply to Julian Chen

TI__Mastermind 41790 points

Hi Julian,

That's correct. To clarify "very small", I mean the T2P voltage will be low based on the current that the apps section calculates which is usually the case to save on efficiency for just a logic signal.

Power management

Power management forum

TPS23754: IT2P SPEC