Dear Sir/Madam, Dear Texas Instruments Team,
I build a converter with the LM5140-Q1. I have seen your evaluation board, described in the SNVU521-July 2016. In your eval board, you create 3.3V and 5V by connecting the FB1 and FB2 pins to VDD or ground. You do not use a voltage divider. However, I need 13.0V output voltage and 5.6V output voltage and so I have to use voltage divider resistors. The feedback divider has got a ground. On your layout, you have got an analog ground plane, which is separated from the rest of the circuit and far away from the power.
My question is: Where to connect the feedback resistor ground to? To the analog ground plane? Or to the power ground? About this, you write neither in the datasheet nor in the application note of the evalboard. And on your evalboard you avoid the feedback resistors.
It would be nice, if you can provide a layout example where you have used the voltage divider resistors, so that I can see and check my design and in case adapt it.
Furthermore I want to ask, if the MOSFET IPB054N08N3GATMA1 can be used? Because I need 13.0V/14A and 5.6V/9A, which is a lot. And I want to use 440kHz.
Many thanks in advance for your help and answer.
Best regards
Hubert
