• State Resolved
  • Locked Locked
  • Replies 3 replies
  • Subscribers 62 subscribers
  • Views 466 views
  • Users 0 members are here
Support feedback
Options
Options
Similar topics

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.

LMZ35003 input current question

Kazuya Nakai59
Guru 20100 points
Other Parts Discussed in Thread: LMZ35003

 Hello guys.

 Our customer wants to know for their current developing products that how much in rush current of LMZ35003 VIN when the VIN voltage is just pulled up

0V to 24V with 1~3 us rising time. Is the current would be about 1A? I know LMZ35003 operation is not started at the moment. But I think it is not 0A. 

 Best regards, 

  • 0
    TI__Guru 57555 points

    It seems to me that this is a very fast rise time on the input.  I think that most of the current will go into the input capacitor(s).  As an example, if the input capacitance is 47uF you would calculate a spike of 47u*24V/1us = VERY BIG.  Of course you will not see that.  With such fast rise times the current spike will be limited by the parasitics of the PCB, input caps, etc.  Also the characteristics of the input supply will impact this current.  So, I do not think that the regulator will have much impact on this very fast initial spike.

    FD

  • 0 in reply to Frank De Stasi
    Guru 20100 points
    Hello Frank,

    Thank you very much for your prompt reply.
    I understood that input current flows into the input capacitor when VIN voltage is pulled rapidly.

    At the same time, how much is current which flows into VIN pin of LMZ35003?
    Almost zero?

    Best regards,
  • 0 in reply to Kazuya Nakai59
    TI__Guru 57555 points

    Yes, the module current would be near zero during this fast initial time.

    FD