TPS23881: Configuration question of Autonomous mode

Ben Chen75

Part Number: TPS23881

Hello,

We are using TPS23881 to design an 802.3bt (90-watt) PSE without MCU. My question is that once

I set Rauto to 7.7K ohm (4-pair 90-Watt) , can it be connected with legacy 2-pair 802.3af/at devices?

If I would like the PSE to support upto 90-watt (from 2-watt to 90-watt for both 2-pair and 4-pair) for each port, should I

use autonomous mode and set Rauto to 7.7Kohm?

Best Regards,

Ben

over 5 years ago

0 Penny Xu over 5 years ago

TI__Genius 15685 points

Hi Ben,

If you set 7.7K for the AUTO pin resistor, all ports would be set to 90W, 4pair, which means TPS23881 would be able to support four 90W ports(2 channels to support 1 port).

The 90W port can power up from class 0 to class 8 PDs which include AF and AT PDs.

Thanks,

Penny

0 Ben Chen75 over 5 years ago in reply to Penny Xu

Prodigy 250 points

Hi Penny,

Thanks a lot!

Best Regards,

Ben

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TPS23881: Configuration question of Autonomous mode