Can I adjust the digital potentiometer for frequencies around 1MHz to 10MHz for adjusting the gain of a video signal?
It depends. Bandwidth is a function of the code and end-to-end resistance RAB. Lower RAB and codes yield higher bandwidth.
10MHz bandwidth or above is possible if you use a 1 kΩ version of AD8400, AD5273 and limit your codes to a low value range or using the AD5258 with a full code range.
Typically a plot is included showing the maximum bandwith (frequency) versus code.
Retrieving data ...