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AD3308 oscillation questions

Question asked by ap00 on Nov 7, 2013
Latest reply on Nov 18, 2013 by seanbrown


I am revisiting the use of the AD3308 after some time away from the project. We are seeing oscillations anywhere from 50 -60 Mhz when I pull the 5 V input up to 5 volts with a 510 ohm resistors. I am level translating from 5 V down to 3.3 V in these cases. It seems as it transitions from low to high or vice-versa, it can get into an oscillation that continues until I power off or connect the input to ground.

I realize there is a <=3 ns minimum rise time specification that I am violating in this case, but is this normal? I have found that putting 100 ohms in series with the input pin seems to alleviate the problem.

This is a new design that we are trying to get in production. The reason I chose the part was because it was bidirectional (which gives me some flexibility going into an FPGA) and 8 in a package, but the speed was not really needed.

Any suggestions?