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,

Philipp

Parents
  • 0
    •  Analog Employees 
    on Oct 26, 2015 9:58 AM

    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.

    Regards,

    Doc

Reply
  • 0
    •  Analog Employees 
    on Oct 26, 2015 9:58 AM

    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.

    Regards,

    Doc

Children
No Data