TPS23753A: Please help to review the schematic diagram of TPS23753A，thanks a lot!

Hi Yi,

- CLS resistor should be 63.4ohms for class 3
- VDD-VSS capacitance must be <0.12uF for successful detection
- Since you are using a 12V adapter, I recommend reading our OR-ing appnote (www.ti.com/.../slva306a.pdf) & work through our flyback design guide (www.ti.com/.../slva305c.pdf) to be sure you have the correct transformer for wide Vin
- Be aware that your voltage divider on APD makes it such that the hotswap FET turns off at 5V (rising UVLO)
- Pole & zero capacitors on the secondary (C44, R37, C46) need to be connected to beneath R40 & above R42
- I recommend just copying the feedback component values from PMP8803
- The output capacitance is much greater than needed. We recommend 3x 22uF or 68uF
- Vc bulk capacitance only needs to be 10uF. 0.22uF bypass capacitance can be located near the Vc pin.
- All 4 bob smith terminations should be connected to a 1000pF 2kV isolation capacitor that is then connected to the BS plane. See the example in PMP8803
- Each of the bob smith terminations are not properly sized. The capacitors should be 0.1uF in series with 75ohms.

I recommend seeing PMP8803 for reference for all of the above the suggestions. In fact, feel free to copy the schematic directly. Additionally, our flyback design guide (www.ti.com/.../slva305c.pdf) is a great resource in case any major redesign is necessary.

Regards,
Tom Amlee
PoE PD Apps Engineer