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UCC28C40: UCC28C40 related issues

jeno.zhang
Expert 2315 points
Part Number: UCC28C40
Other Parts Discussed in Thread: TL431

Tool/software:

Hi，

UCC28C40 was tested at a high temperature of 70 degrees Celsius, and when outputting a load of 1A, the output voltage was too high. The designed output voltage of the product was 5.05V, with a 1% accuracy. However, during the test, there were unqualified products with an output voltage of 5.12-5.15V, and the accuracy of the output voltage could not be achieved. Could you please help analyze the reason?

Thanks！

  • 0
    TI__Guru 53925 points

    Hi

    You need to check to see FB pin voltage, TL431 voltage, VREF, these at 70C may change then check if due to these. 

    You need better temperature accurate TL431.

    R14 connected FB and COMP. You need to adjust that resistor value to be larger since its value affect the gain.