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UCC28180: What is the correct value for C14 in TIDA-00779 schematic

Ng Ka Lung
Prodigy 90 points
Part Number: UCC28180
Other Parts Discussed in Thread: TIDA-00779,

Dear expert,

In the

TI DESIGNS TIDA-00779 REVB Bom, description for c14 is

CAP, CERM, 8.2 μF, 25 V, +/- 10%, X5R, 0603

In schematic C14 is also 8.2uF.

But the part no. written in the BOM is

0603ZD475KAT2A

Which is 4.7uF capacitor.


Which value is the correct one 4.7u or 8.2uF?


Regards

 

Barry Ng

  • 0
    TI__Mastermind 26840 points

    Hello Barry,

    Thank you for your interest in the TIDA-00779 PFC reference design.

    Please take the correct value of C14 as 8.2 uF as shown on the schematic diagram.

    It is often the case that a designer will start with an initial value of some component and later decide to change that value after evaluating the performance of the prototype board.  But instead of deleting the original component and searching the schematic library for the new component, it is expedient to simply change the number of the "displayed value" of the original schematic symbol and the BOM listing.  However the manufacturer's component part number did not get changed, and that is still carried forward into the BOM part number listing.  

    So the BOM part number is in error in this case.  Since the original component case size is 0603, your options are to find an 8.2 μF, 25 V, +/- 10%, X5R cap in the 0603 case size, change the voltage rating to 16V or 10V, or change the part to a larger case size to accommodate the  8.2 μF value.  In the UCC28180, VCOMP voltage does not exceed 5V, so a lower voltage rating is allowable.

    Regards,

    Ulrich