This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

LM25143: CVCC connection and layout method

Guru 19605 points
Part Number: LM25143
Other Parts Discussed in Thread: PMP31202

Please let me know two points below about the CVCC connection method.

①The data sheet described that VCC-PGND1 and VCC-PGND2 are connected via capacitors.

 Does this mean that two capacitors are connected via common PGND?

 The datasheet described that VCC must also be connected, but looking at the datasheet and the EVM layout, it doesn't look like the VCC and PGND1/PGND2 pins are connected with a capacitor.

② PMP31202 has only one CVCC capacitor (4.7μF) connected.

 If I care about the layout, is it okay to connect a single CVCC?

 If there is no problem, is there a recommended layout other than PMP31202?

https://www.ti.com/tool/PMP31202

Best regards,

Satoshi

  • Hello Satoshi

    If two VCC capacitors are used, 

    • Connect the PGND1 pin to 1) the source connection of the CH1 low-side MOSFET and the ground connection of CVCC1.
    • Connect the PGND2 pin to 2) the source connection of the CH2 low-side MOSFET and the ground connection of CVCC2.
    • Connect 1) and 2) should be connected to a common power ground. 
    • Connect the positive connections of the CVCC1 and the CVCC2, the VCC1 and the VCC2 pins together on PCB.

    It is aggressive approach using only one capacitor. I'd like to recommend using two capacitors. 

    -EL