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TPS7A49: Regarding the LDO output if ADJ pin of LDO is short circuited to GND

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Part Number: TPS7A49

Hi there,

We are using TPS7A49 LDO to convert 15 V DC to 5 V DC (Current Requirement: 20 mA). Our 15V DC source can supply maximum current of 200 mA. Please let us know that if the ADJ pin of LDO gets short-circuited to GND in case of any fault, then what will happen to the LDO output voltage? Will it become equal to the LDO input voltage? What would be the impact on load current flowing through the LDO?

Thanks and Regards,

Surya Mohan

  • Hi Surya,

    In the event that ADJ is shorted to GND, the internal error amp will drive the gate of the pass FET all the way on and so VOUT will be VIN - VDS of the pass FET, so VOUT will be close to VIN. 

    For the load current, the RDS of the pass FET becomes small and the output voltage increases, so the load current will increase proportionally for a resistive load. 

    Best regards,

    Nick

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