TMS320F280049-Q1: VDD decoupling capacitor

Hi RV,

Riccardo Villani said:

VDD --> TI recommends placing a decoupling capacitor near each VDD pin with a minimum total capacitance of approximately 20 µF. (pg.26 datasheet)

This means that a 5uF decoupling capacitor must be placed on each VDD pin. Can you confirm? 

The requirement is that the min total capacitance on VDD is 20uF. You can either split this evenly between the VDD pins or place a bulk 20uF shared by all the pins with a small 0.1uF for each VDD pin. How you split the capacitors is really not very important. What is more important is that the caps are very close to the device pins.

Riccardo Villani said:

While for VDDIO_SW --> If the internal DC-DC regulator is used, a bulk input capacitance of 20-µF should be placed on this pin. (pg.26 datasheet)

This means that 20uF bulk cap must be placed on each VDDIO_SW. Correct?

There is only one VDDIO_SW pin. The requirement is to place 20uF capacitance on VDDIO_SW. You can place 0.1uF on each VDDIO pin. By the way keep in mind even in DC-DC use case, VDDIO_SW and VDDIO pins have to be supplied from the same source.