TPS56628: TPS56628DDA_5V Layout Verification

Hi,

Please see my comments regarding 5Vout rail:

SCH:

- EN: Because EN pin is active high, make sure to a power source high enough connected else device won't turn on. you have EN resistors R1955 and R1956 as DNP so that is why I note this. If you will be using VCC_REG3_IN to for enable, you may need a 0-ohm resistor instead of DNP for R1955 to ensure connection. If you have a noisy source/surrounding to where you think EN would go below threshold, it would be best to add a pull up resistor. Our schematic uses a 10kohm.

- PG: Rpg resistor value, which is connected between PG and VREG5, is required from 25kohm to 150kohm. You currently have it as 0-ohm. As for R407, what is the purpose of it? Standard design should be fine without it.  

- CFF (C1666): the cap across top FB R should be within 1-22pF range, you currently have it as DNP but the value is 150pF, best is to stay within recommended range as per table 1 in DS to ensure stability.  

LAYOUT:

- Couldn't open file due to error:

however you can check main layout items:

- keep GND plane below IC for thermal purposes

- keep current loops short (SW/VIN/COUT)

- even tho device doesn't have an AGND pin, you still need to isolate grounds for analog (EN/VFB/VREG5/PG) from power signals (rest of pins).    

- ensure to keep components close to IC specially caps, fb resistors, boot cap and vreg cap. 

Regards,

Eileen