TPS23861: TPS23861 Schematic consultation

Hi Darren,

Please see my answers inline below. 

1.how the TPS23861 work mechanism?

[Penny]TPS23861 has 4 modes: Off, auto, semi auto and manual mode. Please refer to TPS23861 datasheet section 7.4 for more details. 

2.that's the function of SDAI and SDAO, if use I2C，which PIN is need to connect？SCL and SDAI  or SCL and SDAO,becuase from the schematic, the SDAO is not be used

[Penny]If you need I2C to control the device, you will need SCL, SDAI and SDAO. Please refer to TPS23861EVM-612 for reference. 

3.we only need output power 6W, how to Configuration，pls help provide the way how to complete it

[Penny]You can configure the port current limit through register 0x2A and 0x2B. But it only has 6 options: 110mA, 204mA, 374mA, 592mA, 645mA,754mA and 920mA. If you need exact 6W power limit, you can use TPS23882 which as 0.5W step for port power limit.  

4.the datasheet recommend the schematic as the first Figure is connect to PHY port direct is not conncet to port by common mode inductor as the second figure, what's the  functions of Common mode inductor?

[Penny]The common mode inductor is not needed unless your power supply's output has noise and you want to filter the noise at the port.  

5.from the schematic can be know the VPWR 48V is connect to the PHY port, so how the TPS23861 control its disconnet?could you help to descible this issue comprehensively.

[Penny]The port would be turned off if the PD is removed or the current falls below 7.5mA. You can also disable the port through I2C command(0x19 register).

Thanks,

Penny

Hi Darren,

Please refer to TIDA00465 for 1 port design. Please make sure you connect the PSE port output to pair 12 and 36 which is called Alternative A wiring, Thanks. 

Best regards,

Penny

Hi Darren,

Please copy our EVM design if using integrated solution (magjack) or TIDA00465 for discrete solution (data transformer + RJ45). Thanks. 

EVM:

TIDA00465

Thanks,

Penny