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LM5021: VCC function issue

Jiaqi Wang
Intellectual 2220 points
Part Number: LM5021

Tool/software:

Hi team,

My customer is using LM5021 in their project and wants to know the MAX voltage of VCC pin. Customer is using this device with an external power suplly at arround 14V. What is the voltage level of this external power to keep no risk? Please kindly find the SCH below. Thanks!

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Br,

Jiaqi

  • 0
    TI__Guru* 86266 points

    Hello,

     

    I reviewed the data sheet for the LM5021 and there is not an absolute maximum rating so it is meant to be powered from the Vin pin that is supplied with an aux winding.

    I can see that at 14 V input this is not possible.  This is general purpose PWM.  You can use one of the UCC28C4x devices instead that will operate with VDD voltages of 14 V.

    If you have questions on how to design with the UCC28C4x devices in your application please repost in the e2e with the UCC28C4x in the title so the appropriate applications engineer can help you with your design.

     

    Regards,

  • 0 in reply to Mike O'
    TI__Intellectual 2220 points

    Hi Mike,

    This design is widely used in customer's project for over tem years. It's hard for them to change to a new one so quickly. Customer wants to know the max voltage off VCC. Could you help check internally for this? Thanks!

    Br,

    Jiaqi

  • 0 in reply to Jiaqi Wang
    TI__Guru* 86266 points

    Hello,

     

    The LM5021 was designed to have VCC regulated from VIN.  It is not advisable to bias VCC with an external aux supply.  That is why there is not an absolute maximum rating for VCC in the data sheet.  The VCC pins was not meant to bias with a separate bias supply.

     

    Regards,