INTEGRA M2106 heating: power supply problem?

Hi, I’m using M2106 module.

For a test I’ve been using a laboratory power supply. All works correctly.
For PCB use, I made a 5V power supply with L5972 DC-DC converter.
Now I measured with multimeter, it says 5 volt, but module heats a lot.
What’s wrong?

by ‘module’ you mean “M2106” or your DC-DC converter?

I mean 2106.
I don’t know why, but sometimes it works, others not.
I read 0,9A @ 5 volt.

I noted this: when I power the 2106 @5V from desktop power supply, I have for a while about 100mA of current.
If I unconnect the power plug, then I quickly connect it again, I have about 900mA of current in the module.
Maybe I’m wrong with power-up procedure?
Should I keep the 5V for a minimum time before switch-off the power supply?

There is a diagram in the module’s data sheet that shows the required power-up and power-down sequence.

You should certainly avoid just pulling the power!! :open_mouth:

I have to make a board compatible with WMOi3 and M2106 module.

WMOi3 datasheet:

M2106 datasheet:

I have a doubt: in the board I have the ON/~OFF pin is directly tied to Vcc (+5V), is this the problem?
Have I to power on the module (+5V), wait a delay with ON/~OFF= 0, then keep ON/~OFF pin to 5V?
I think would be a bit strange: I have the same behaviour with M2106 and WMOi3.

By the way, I’ve seen there is a diagram in datasheet, but if power faults (e.g. during a storm) and I don’t make the correct power-up sequence (for a while there isn’t power supply, then it comes again, it could happen), this will burn my modem?