The power is good in LTPowerPlay, but my Power Good output is not pulling low.
The LTM2987 does not intend to pull it low, as seen by the pad register.
I have connected channels to the MFR_PWRGD_EN register:
What's going on?
Thanks,
Ethan
LTM2987
Recommended for New Designs
The LTM2987 is a 16-channel µModule® (micromodule) Power System Manager used to sequence, trim (servo), margin, supervise, manage faults, provide telemetry...
Datasheet
LTM2987 on Analog.com
The power is good in LTPowerPlay, but my Power Good output is not pulling low.
The LTM2987 does not intend to pull it low, as seen by the pad register.
I have connected channels to the MFR_PWRGD_EN register:
What's going on?
Thanks,
Ethan
Power Good is active high, so NOT LOW means power is good. In the LTC2977 datasheet the bit is named "Mfr_pads_pwrgd_drive." I see in LTPP it is named PWRGDB_DRIVE, as if the "B" means active low, but it is not active low.
Power Good is active high, so NOT LOW means power is good. In the LTC2977 datasheet the bit is named "Mfr_pads_pwrgd_drive." I see in LTPP it is named PWRGDB_DRIVE, as if the "B" means active low, but it is not active low.
I'm not sure what you are trying to communicate. Are you saying that the PWRGD signal is behaving as expected? This doesn't make any sense to me. Shouldn't the Open Drain output be pulling the PWRGD output pin net low?
I am saying it is behaving as expected. Even though it is open drain, it is active high. I have confirmed with the team that the B in the bit name should be removed.
It is active high open drain so that multiple parts can connect to the same power good net and all parts have to release the net for the whole system to be in the power good state. Any one part without power good brings the net low to indicate the power is not good. Basically, a wired OR function.
Thank you very much, I understand now.