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excessive current consumption

Question asked by laszlo zsebe on Aug 12, 2014
Latest reply on Aug 28, 2014 by laszlo zsebe

Hi,

Does anybody have an idea why an otherwise working MC68HC908JL8 would consume around 100mA? Of course it heats up, of course it sucks the juice out of the power supply...

I am using it with RC oscillator, the freq is correct.

It happens almost 50% of the 40 pieces I tried by now.

Pulling down RST will stop the over-current, even if the (test) program only has configuration.

Changing the controller USUALLY does not solve the problem.

I use them in another product where they perform wonderfully. There I use 3.3V supply; the failing ones get 5V.

It could also be a PCB layout issue, as the 5V regulator is about 7" away from the controller. The supply traces are wide with no loop; everybody got their own .1uF near the supply pins.

 

Running out of options/time.

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