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TPS7A4001: Safety distance between Vout pin and VFB pin at HV

TISL
Expert 4640 points
Part Number: TPS7A4001

Dear e2e Community,

My customer uses our HV LDO in this configuration:

-        Vin = 90V DC
-       Vout = 84V DC
-        Iout = 10-20ma peak 

The issue is about the distance between Vout pin and VFB pin. Due to the package, this distance will be in worst case : 0.27mm (0.65-0.38)

The Standard regulation (IPC-2221B) requires that the minimum spacing between 2 conductors should be 0.6mm if the voltage difference is around 80V

 

Questions
-        What would you suggest in order to safely use the TPS7A4001 in this configuration ?
-        Could we say that even if the local spacing between VFB & VOUT is thin, the possible leakage current will still be neglectable compared to the current going through the resistor network divider ?

Regards,

  • 0
    TI__Expert 7035 points
    Hi Tisl,

    Unfortunately there isn't much we can do if that spacing is required to meet that standard. One thing that you could try is adding a conformal coating over the device that may better help isolate the two conductors.

    Yes, we can say that even though the spacing between the two conductors is small that the current through the resistor divider should dominate any leakage current through parasitic paths. However, if there is some leakage current present it will result in only a minor drop in accuracy.

    Hope this helps.

    Best Regards,
    Mark