TIDM-TM4C129POE: Need to know output specification of this implementation

Tom Halliday55

Part Number: TIDM-TM4C129POE
Other Parts Discussed in Thread: TPS23753

We are interested in using the TPS23753APW for our IoT Arm Cortex design. We have the reference design TIDM-TM4C129POE and can see that the PoE topology produces a 5v rail and also a down reg'd 3.3v).

What information cannot be found is the max current that can be drawn from the 5v rail. In the specification for the TPS23753 it states 405mA, but there is no information on the output voltage that refers to, conversely in the reference design you can see it is specified for 5v, but cannot see the max current you can take from that rail.

Please advise.

Many thanks

Tom

over 8 years ago

0 Darwin Fernandez over 8 years ago

TI__Mastermind 41800 points

Hi Tom,

Looking at the schematic, this is a 5V/2A converter. Please let me know if this helps! Thanks!

Regards,
Darwin

0 Tom Halliday55 over 7 years ago in reply to Darwin Fernandez

Prodigy 20 points

Hopefully it does help. Can you tell me what voltage the 405mA capability of the PoE converter refers to? And how you conclude it's a 5V/2A output?

Kind regards

Tom

0 Darwin Fernandez over 7 years ago in reply to Tom Halliday55

TI__Mastermind 41800 points

Hi Tom,

We design the PoE converter per the power transformer spec rated for 5V/2A (to also stay within the PoE PD max power spec).

The 405mA refers to the voltage the PSE delivers after 100m of cat5e cable. Per the IEEE the standard, the voltage range at PD input is 37-57V for Type 1 applications. This means the PD is capable of 15W before it hits current limit. However, if connected to a PSE that's compliant to the IEEE standard and with 100m of Ethernet cable (also per the standard), the max PD input power is limited to 13W (the 405mA simply adds margin). Thanks!

0 Thomas Lewis over 7 years ago in reply to Darwin Fernandez

TI__Expert 5615 points

Tom, Has this answered your question?

We think it is resolved but would appreciate your agreement.

Thank you for interest in PoE products from Texas Instruments,

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TIDM-TM4C129POE: Need to know output specification of this implementation