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TPS7A4001: Can I use this part number to built negative rail ?

Lucas Oliveira
Prodigy 80 points
Part Number: TPS7A4001
Other Parts Discussed in Thread: LM337

Tool/software:

Hi,

I've been designing a bipolar SEPIC converter (+60V / -60V) and would like to incorporate an LDO in the circuit. Is it possible to use the TPS7A4001 on the negative rail by connecting -60V as ground and using the actual ground as the positive voltage?

Best regards,
Lucas

  • +1
    TI__Mastermind 36885 points

    Hi Lucas,

    It's usually better to use a dedicated negative LDO.  The issue with this technique is that system GND is cut, which can be problematic for system grounding.  If you have assessed the risk with the system grounding and it is acceptable to interrupt GND then the LDO will work just fine like this.

    The LM337 is a negative linear regulator which has an abs max rating from Vin to Vout of -40V.  There is no enable pin so it will simply rise with Vin.  If the output of your LDO is less than -20V on the -60V input then this is another option you may consider.

    Thanks,

    Stephen