LM27403: On the operation of PGOODpin

Hello.

thank you for your answer.

When connecting to VDD, I believe there will not be a rise. However, the power supply we are considering may be pulled up with another 5 V or less power supply.
In the case of a device connected to the PGOOD terminal and a constant voltage LOGIC, once the device recognizes H as 1.1 V, it will be recognized GOOD once.
Why will I get a voltage of 1V? (There are devices that generate voltage and do not come out.)

Thank you.

Ishii-san,

I am sorry, did not understand your question. Please illustrate with a figure if possible.

Regards,

Mathew

Hello.

Thank you for your response.

Detailed contents are described in the attached document.

please confirm.

Thank you.

LM27403-6.pdf

Hello,

PG of LM27403 needs 100uA current for pull down. I would recommend changing the 80K to 15K or lower. Also would be good to verify operation independently without hooking upto EN of TPS61010 and then with it hooked up. the PG pin is an open drain pin.

Regards,

Mathew

Hello

Thank you for your answer.

As I gave you advise, I experimented with a pull - up resistor under 15 KΩ.

The results are attached.

It did not improve.

What is the cause?

Thank you.

LM27403.pdf

Hello,

Did you try a new IC on the board to verify if it was damaged?

Regards,

Mathew

Hello

Thank you for your reply.

Yes.

EVM and our board also have the attached waveform.

Currently, 3 pieces are the same in the same state.

Thank you.

LM27403-7.pdf

Hello

Waveform data Thank you.
I understood that good Devices has this waveform.

Is the timing of this part inspected by shipment inspection at your company?
If you are inspecting, there is a high possibility that the characteristics have changed in the implementation (destroyed?).
In the case of destruction, is there a high possibility that FET of PGOOD is destroyed?

Thank you.

Hello,

If you think the parts were damaged and PG was pulled up to VDD and not Vin, then its better to submit for FA. All pin functions are tested at factory and yes the FET of PGOOD can be destroyed if pulled up to higher than rated voltage.

Regards,
Mathew