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AD9233 oscillation

Question asked by MatteoFattori on Apr 13, 2018
Latest reply on Apr 16, 2018 by THA

Hello, we are developing a new acquisition unit with AD9233, we design the  antialea and the FDA chain to drive the ADC. 

We product more or less 20 sample (ten layers board with Zynq ecc) but in only one sample we found a 27MHz  oscillation (500mVpp)  from the converter..

the first time my through  was the FDA amplifier which oscillate for that i revome the inductor to isolate the ADC and FDA, and the oscillation goes to 15MHz about  (quite sinewave, not perfect) is from the ADC. this signal is common to Vin+ and Vin-  and CML. 

Could a bad quality capacitor (0402 ) 100nF connected to REFT and REFB do this problem?

Thanks in advance.

Matteo

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