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TPS7A4001: Will this device work correctly?

Part Number: TPS7A4001

Hello Experts,

My customer is considering to use TPS7A4001. He would like to confirm whether the attached circuit will work correctly or not. Would you please review it?
Question_TPS7A4001_(09142020).xlsx

Best Regards,
Fujiwara

  • Hi Fujiwara,

    Please help me understand the problem a little better so I can be of better help.

    1. What net is SG? On the schematic the label points to open space so I'm not sure what it is referring to.
    2. It says that the GND terminal will be referenced by the reference potential (not SG). Is that referring to the net that GND is connected to in the schematic?
    3. I see diodes for half-wave rectification. Is the expected input to the TPS7A4001 a half-rectified signal or am I missing something/am I looking at it wrong?
    4. What is the purpose of R3 at the output?

    Best regards,

    Nick

  • Hi Fujiwara,

    The customer is correct and the issue is with the linear regulator model.  The older linear regulator spice models were not designed to be simulated in a floating application like this.  The TPS7A40 can perform just fine as the customer has drawn in the schematic.  The biggest concerns I have will be the sizing of R1, R14 and the zener diode.  The customer should make sure that the resistors are sized appropriately to handle the load current of the TPS7A40 and the zener current of the zener diode.  They should also make sure that the zener diode is sized appropriately to handle the power drop for the minimum load on the TPS7A40.

    Thanks,

    - Stephen