TPS546D24A: TPS546D24A

Saurav Kumar 

If you are getting N/A for the VSEL resistors for a 0.82V output voltage. 

Go to the Pin Detection tab

Cell D10 should be the VOUT Range, select 0.75 - 0.89 @ 0.01

If G20 and H20 are still showing #N/A it's because the VOUT_COMMAND is not exactly matching the value in the look-up table.  Select cell D11 and pick 0.82V from the drop-down menu.

The Bottom Resistor in cell G20 should be 17.8kΩ and the top resistor in cell H20 should be 59kΩ

These values should match divider code 1 and resistor to ground code 7 from Table 7-17 in the datasheet.

Vout - VOUT_COMMAND(offset) / VOUT_COMMAND(step) = ( 0.82 - 0.75 ) / 0.010 = 7

What other problems are you having with the pin programming tool?

Saurav Kumar said:

 I can see a note written in PinStrap excel sheet (Option is not available in Pin Strapping).

What does it mean? And what should be the switching frequency for 0.82V output @35A.

If the Text is yellow, using the "Design Caution" formatting listed above, the selected switching frequency is not programmable via Pin Programming and must be programmed using PMBus.  550kHz is pin programmable, so the cell is using black text.

550kHz will work fine for 12V to 0.82V.

If you desire higher efficiency, you can reduce the switching losses by reducing the frequency to 450kHz or 325kHz.

If you need a smaller size, you can increase the switching frequency to 650khz, 900kHz, or even 1.1MHz.

Saurav Kumar said:

I have observed difference in PinStrap registor values in Webench and Pin Strap Excel sheet resistor value.

There are a number of common pin-programming options that are available with multiple resistor options, especially options that have no resistors (floating or shorted to ground) or are programmed with only one resistor to AGND and no pull-up to BP1V5.  It is possible that the WeBench programming is selecting two resistors for those options when the excel design tool is selecting the option with fewer resistors.