Issue with PG at MPM3510A


we use a MPM3510A to convert +36V into +5V. We have connected a LED with cathode to the PG signal. We connected +5V via resistor of 270 Ohm to the anode of the LED. We see a short flash when we enable/disable the MPM. But in on state LED stays off. Datasheet only states that it is an open drain signal which may drive up to 4 mA.

Can you explain this behaviour?

We use another MPM3506A with the same circuit. Difference is that we convert from 36V to 30V and have another LED resistor of 2k7 to +30V. But the LED is on when the MPM is on.

Thanks in advance, Sven

Hi Sven,

Welcome to the MPS Technical Forum! Can you please share a schematic of both circuits? What is the p/n and Vf of the LED you are using? High volume customers can also send their questions to for specialized support from our FAE team.


first image shows the MPM3510 which does not properly control the LED.

Second image shows the MPM3506A -sorry must take another post as i am a new user :(.

LEDs are Kingbright standard LEDs with typical Vf=2.2V at 20 mA.

Regards, Sven

And here is the second image: