AnsweredAssumed Answered

AD7983 input driven by multiplex signals

Question asked by jake65892 on Oct 18, 2011
Latest reply on Oct 18, 2011 by CatherineR

I want to drive the AD7983 with a multiplexed signal.  I am having a hard time understanding the best time to switch the multiplexor based on the timing diagram in the datasheet.

 

I would like to switch the multiplexor as soon as possible after the rising edge of the CNV pulse in order to maximize the settling time of the next signal's driving circuitry.  So, I would raise the CNV, wait for the converter to "do its thing", and then switch the mux.  How long must I wait for the converter to "do its thing" before I change the input, without degradation of the conversion.

 

Looking at the datasheet, I cannot tell if this time is t_CNVH, t_CONV, or some other time.  If it is in fact t_CONV, what causes the 300 to 500 ns span?  And which should I use, 300 or 500?

Outcomes