We have this really strange problem with a regulator on a circuit we have.
Usually it outputs a good 3.3V , from an input source of 5V. When we consume more current from the 5v source (not the REG output) , we get a voltage drop from 3.3V to 2.8V on the regulator output itself.
This happens only when we pass the 1.5A from the source itself.
The 5v source is capable of 4A , and it happens when we consume about 1.6A from the source. The source stay at 5V when the REG drops.
Please check the REG schematics here (c14, and c15 are in place) :
- the regulator output is consuming less then 100mA.
- I found out that the transformer source is indeed 4A output, but it says 0.68A maximum input - is that changes things ? how is that possible ? we replaced a few of them, non worked.