mic502 testing

Thread Starter

csy

Joined Feb 8, 2010
3
hi, in magnetic levitation project,i am using a fan management chip from Micrel (MIC502) as a driver to produce PWM to h-bridge LMD18201.
but based on the datasheet of MIC502, input VT1 will affect the output at pin7, and the output should be a pulse waveform..
i supply VDD with 5V, VT1 with 1.5V to 3.5V, capacitor at pin2 is 0.1μF that is 30Hz, and pin3, pin4, pin5 to ground...but i cant get the PWM output,why?

i have tried many ways to test it, but no PWM is produced..
i wonder is it my mistake to test it or the ic itself is burnt?
can i have some suggestion on how to test the MIC502?
thanks a lot..
 
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