I'm using MP2359 for converting 12V from 20V.
I'm using the recommended sch and layout designs (SCH on the first page).
My resistors are 2K and 24K to have 12V, and I use the recommended Wurth inductance just for being sure about everything. My Schottky is SS24, which is basically the same as the recommended one (it's not available in my place).
Now P#4 (Enable) is connected to P#5 (In) thorugh a 100K resistor to enable immediately as there is voltage on the input side, and I have a tact switch also on P#4 which connects it to GND when I press it. (Reset button)
Currently there is no load on the output, just a 22uF capacitor. (will drive relays later)
If I turn on the input power, it creates 12V nice and smoothly.
However, if I press the reset button, and release, the chip dies, and shorts P#5 and P#6 (input and output), resulting high voltage on the output.
I'd love to hear something useful of the root cause of this. Burnt 6 pieces just today while trying to analyse what is happening.
What I have tried?
- I was constantly monitoring the output at the capacitor.
- If I turn down the input, after a few seconds voltage collapse to 0.
- Turning it back again output goes up to 12V.
- Repeated this a few times (but always waited for the 0 voltage after turning off) -> always succeeded.
- Then push the reset button (Enable pull down to GND), wait for 0V @output.
- Upon releasing the reset button, output goes above 12V until it reach the input voltage.
DC5V has a load of a microcontroller. DC12V has currently no load on it (it is connected to a SI2307 P-MOSFET's source)
After pressing the TACT, MP2359 on the left dies, but MP2359 on the right doesn't.