LM7310: Tying PG pins together on multiple LM7310

user6551401

Part Number: LM7310

I am using two LM73100PWR ICs as ideal diodes in an OR configuration between two power supplies to my system. The two power supplies cannot mechanically ever be plugged in at the same time, so only one LM73100PWR will ever be on at a time.

Is it ok to route the PG pins together to the same MCU I/O?

If the LM73100PWR is not powered on, will the PG pin be floating, or will it be tied to ground?

Thank you.

over 3 years ago

0 Kunal Goel over 3 years ago

TI__Guru 50335 points

Hi ,

Welcome to e2e. PG is an open drain pin. When there is no supply to the device, the PG pin is expected to stay low. However, there is no active pull-down in this condition to drive this pin all the way down to 0 V. If the PG pin is pulled up to an independent supply which is present even if the device is unpowered, there can be a small voltage seen on this pin depending on the pin sink current, which is a function of the pull-up supply voltage and resistor. Minimize the sink current to keep this pin voltage low enough not to be detected as a logic HIGH by associated external circuits in this condition.

Do you want to short the PG pins of two device?

Regards

Kunal Goel

0 user6551401 over 3 years ago in reply to Kunal Goel

Prodigy 60 points

hey Kunal,

Yes I am hoping to short the PG pins of two devices. Only one will be powered on at a time. Will this cause any problems?

thank you!

0 user6551401 over 3 years ago in reply to Kunal Goel

Prodigy 60 points

hey Kunal,

Yes I am hoping to short the PG pins of two devices. Only one will be powered on at a time. Will this cause any problems?

thank you!

0 Kunal Goel over 3 years ago in reply to user6551401

TI__Guru 50335 points

Hi ,

Will there be any scenario when both supplies are on? or you are turning on one supply at a time and then you turn off one when second is on? Need to verify this once. I will get back to you by monday.

Regards

Kunal Goel

0 user6551401 over 3 years ago in reply to Kunal Goel

Prodigy 60 points

No, they cannot both be connected at the same time; there is a mechanical block to prevent this. Thank you, looking forward to your answer!

+1 Kunal Goel over 3 years ago in reply to user6551401

TI__Guru 50335 points

Hi ,

Since only one supply is present at a time it would be fine to connect PG pins together. When both supplies are present then you should monitoring each pin individually .

Regards

Kunal Goel

0 user6551401 over 3 years ago in reply to Kunal Goel

Prodigy 60 points

thank you!!

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LM7310: Tying PG pins together on multiple LM7310