TPS798-Q1: Questions to the TPS798, TPS2660, LM5155 and MSP430FR2476 in the “IEEE 802.3cg 10BASE-T1L Power over Data Lines Powered Device Design” Application Note

Tool/software:

Dear Experts,

I have some questions regarding the “IEEE 802.3cg 10BASE-T1L Power over Data Lines Powered Device Design” Application Note:

1. LDO Usage for 3.3V Supply:
   Is it necessary to use the TPS798 or another LDO to obtain a stable 3.3V supply for my microcontroller, or can I connect my microcontroller directly to the PWR line? I noticed that the 3.3V from the LDO is also used for the SCCP circuit, but I will not use the SCCP in my design.
2. Power Supply Turn On/Off (V_on, V_off):
   According to the 802.3cg standard, there are specific power supply turn-on and turn-off voltages (V_on, V_off). How is this implemented in the design? I saw in the application note that the eFuse turns on when the voltage rises above its UVLO value. Is this UVLO value the V_on (19.2V)? How is V_off implemented? Is the UVLO value of the DC/DC converter used for V_off?
3. Use of Isolated DC/DC Converter:
   Why is an isolated DC/DC converter used in the design? Is galvanic isolation required for the power source, or was this chosen for use in intrinsically safe areas?
4. MSP430FR2476 Firmware:
   Was any code written for the MSP430FR2476 in this design, and is it possible to obtain this code?

Thank you very much for your support!

Best regards,
Lauris