TPS549A20: store to NVM or set everytime

Hi Fred,

Fred Cheng said:

• if my customer application is similar to server, 

but he doesn't want to change the setting to NVM before production,

can he set the PMBus everytime  the device wakeup? 

in other word, means the PMbus master (EC) has to store this code for TPS54920.

Yes, you can configure with PMBus every time without setting it to NVM. However, if you are configuring to settings other than the factory defaults, I recommend keeping the power conversion disabled by keeping EN low to avoid any converter activity during configuration.

Fred Cheng said:

what do we have to be careful if my customer want to use default setting ?

The device would work perfectly fine with the default setting. Just make sure the circuit is designed based on the factory default. You can find the factory default settings for the parameters in the datasheet.  

Hi Fred,

TPS549A20 does not have a VOUT or IOUT monitoring through PMBus. The closest would be the STATUS_WORD register [79h] which indicates an overvoltage or overcurrent event.

Hi Fred,

You can check out these devices:

• TPS546C20A, TPS546C23
• TPS546A24A, TPS546B24A, TPS546D24A
• TPS544B20, TPS544C20

Hi Fred,

They are all popular devices used in server applications. However, since you initially chose TPS53915, a 12A device, I would suggest TPS544B20. 

• TPS546C20A, TPS546C23:
  • 35A, 2x stackable
• TPS546A24A, TPS546B24A, TPS546D24A
  • A is 10A, 4x stackable
  • B is 20A, 4x stackable
  • D is 40A, 4x stackable
• TPS544B20, TPS544C20
  • B is 20A
  • C is 30A