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ADP125: Protection diode required?

Hi everyone,

I'm designing a circuit with some ADP125 LDOs for the analog supplies. In the abs. max. ratings, there is a requirement for VOUT:

VOUT to GND | -0.3V to VIN

This would clearly indicate that the regulator needs a reverse diode from VOUT to VIN, however, this is not present on the evaluation board. Since the pass transistor is a P-channel MOSFET, I'd expect there to be an internal diode anyway. So is there still an external Schottky required?

Thanks. Best regards,


  • Hi Philipp,

    You shouldn't be able to force VOUT higher than VIN unless you connect an external supply to VOUT. The restriction is for both the the protection diode which is from VOUT to GND and the body diode which is connected in parallel to the pass transistor. Turning on either of these diodes will damage the part.

    Hope this helps.



  • Hi Doc,

    thanks for your response! I won't supply external power to the output, it's just about the capacitance which is there and must be discharged. Since you mention a body diode and a protection, I suppose that the part has both and hence, I don't need to worry.