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ADM7151 oscillation

Question asked by clevy Employee on Feb 22, 2016
Latest reply on Feb 23, 2016 by Jason_Duan

Hi,

 

I'm using the ADM7151 to supply a PLL/VCO.  It is to be supplied w/ 5V input and give 3.3V output.  See my schematic below.  However the output is actually going to ~4V @ Vin=4.5V, and 4.3V @ Vin=5V.  It's also oscillating badly.  I noticed that my schematic omitted CREF which is in the datasheet as 1uF.  Do you expect this would cause the oscillation and the voltage error?

WP_20160222_002.jpg

Thanks

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