Hi, I am using MPM54304GMN-0002 and MPM54304gmn-0003 in my design. The power output from the 0002 comes up in the right order and value. For the 0003 variant however, I am seeing that Buck1 FB voltage is at 1.2V and the VOut1 is 1.8V instead of 0.9V as designed for. The FB resistor values have been verified to be correct.
I have removed the IC and verified that there are no shorts at PCB fab level. When I probe the IC pins (when IC is mounted and board not powered) I see only 0.2ohm impedance between VOUT1(14,15) and VOut2 (8,9) pins. Is this normal? When they are not connected in Parallel, shouldn’t the impedance be higher?
Also, When probe the pins on bare PCB (without the IC mounted), I see much higher impedance, indicating, they are not shorted on the PCB fab.
please help!
Hello,
For the -0002 suffix, VOUT 1 and 2 are paralleled together. For the -0003 suffix, VOUT 3 and 4 are paralleled together.
Are you saying that the impedance between VOUT1 and VOUT2 for the -0003 suffix is 0.2mOhms? This would make some sense for the -0002 suffix as they are paralleled together.
Does this behavior continue as with a new -0003 suffix module in place? If you reprogram the -0003 sufix module to have the same settings as the -0002 suffix, do these issues also persist? This should narrow things down to see if the module is the issue.
Finally, if the -0002 suffix works well without issues, why use the -0003 suffix?
Best,
Krishan