LM74930-Q1: instability issue during starting

Part Number: LM74930-Q1
Other Parts Discussed in Thread: LM74930

Tool/software:

Hello,

we are using LM74930 on several designs and we are experiencing similar issues as explained on:  LM74930-Q1: Fails to activate output if input/output capacitance ratio is insufficient .

Weeks ago we open a case to share the issue and no solution was defined. This is the case we opened:  LM74930-Q1: Inrush Current / Voltage Instability During Startup 

It is very important for us to solve this instability issue as we are using this IC on several design for protection purposes, and we are experiencing similar issues on all the designs. If hold up capacitor is large enough, the system is not able to turn on because of it is on unstable operation during the starting transient.

It is crucial for us to find a solution, please, support us to define actions which lead us to find a solution.

Thanks in advance.

  • Hi Manuel,

    I see VA is falling low which can mean DGATE is toggling and cause charge pump to fail.

    OR

    If VA is falling, maybe VIN is falling as well and hence causing UVLO to hit.

    Can we confirm if any of these is happening?

    Regards,

    Shiven Dhir