Mtolesen
Newbie level 4
I got a problem, i need 3,3 volt for a mems microphone test, so got some small SMD version (SOT223) UA78M33CDCY voltage regulators.
They are connected the standard way, 0,1 nF to ground on output, and 0,33 nF on DC input to ground, and i also had a 560 ohm resistor on output to ground to ensure some current draw.
Here is the problem, it regulates fine to 3,3 volt at input supply voltage betveen 5 to 11 volt, but above 12 volt in, it suddenly raise output voltage dramatically, 5, 6,7 volt, and then often burn off, sending input voltage directly to output.......
At 14 volt....the output has raised from 3,6 volt, into 7 volt.....
As i can read from datasheet, these regulators shoul be able to take Vin from 5 to 25 volt........so why are mine crashing above only 12 volt?
I have tried ti raise the out cap into 10 uF....that did not help either.....what can be wrong?
They are connected the standard way, 0,1 nF to ground on output, and 0,33 nF on DC input to ground, and i also had a 560 ohm resistor on output to ground to ensure some current draw.
Here is the problem, it regulates fine to 3,3 volt at input supply voltage betveen 5 to 11 volt, but above 12 volt in, it suddenly raise output voltage dramatically, 5, 6,7 volt, and then often burn off, sending input voltage directly to output.......
At 14 volt....the output has raised from 3,6 volt, into 7 volt.....
As i can read from datasheet, these regulators shoul be able to take Vin from 5 to 25 volt........so why are mine crashing above only 12 volt?
I have tried ti raise the out cap into 10 uF....that did not help either.....what can be wrong?