The ADL5336 has a low frequency oscillation.  How do I fix this?

Document created by jdobler Employee on Aug 9, 2013
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It has been observed that while toggling the MODE pin from either low-to-high or high-to-low while the part is powered-up and the GAIN1 and/or GAIN2 pins set to 30 mV or lower, that the DUT breaks out into oscillation, usually with a fundamental frequency of about 10 MHz.  The behavior is common to both VGAs, so it oscillates whether in a cascaded arrangement or not.  It is also digital gain independent.  Rise time of the edge applied to the MODE pin does not seem to affect anything, i.e., a slow edge rate causes the DUT to oscillate as well as a fast edge, milliseconds to nanoseconds, respectively.  Cycling the power supply kills the oscillation. 

 

Once the part is powered-up, we recommend not toggling to MODE pin.  If the user must toggle the MODE pin while the part is powered-up, only perform this operation with the  GAIN1 and GAIN2 pins set to a voltage no lower than 100 mV, to be safe. 

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