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ad9958 - glitch after write to ACR in Linear Sweep Mode

Question asked by sciospec on Apr 5, 2012
Latest reply on May 1, 2012 by DSB



I'm using ad9958 in Linear Sweep Mode to ramp up and down between different DC levels. To ramp up from a level to a higher one I do the following:


- (profile pin is set to '1')

- set the current voltage level to ACR[9:0] (ACR[9:0] now equals CW1[31:22])

- IO update

- set profile pin to '0'

- set the target voltage level to CW1[31:22]

- IO update

- set profile pin to '1'


In principle this works fine except a glitch I get on the output signal after asserting the first IO update. Is there a possibility to prevent the DAC from producing that glitch after changing the content of ACR?


For the sake of completeness - using Output Amplitude Control Mode seems not to be possible for our purpose, because it does not allow to ramp down to a certain voltage level (except 0V).


Many thanks in advance!