I'm using ADG601 as shown in the image above. When I provide an high value to SHDN i can correctly see VBatt = +VH. On the other hand, when I provide a low value to SHDN i can not see +VH = 0 V.
Can someone help me in understand why?
Thank you very much.
Is it possible to have a scope shot showing your results? Can you place the scope probes on the nodes VBatt, SHDN, and +VH? IT would be better if you could show the result when you toggle the SHDN node to logic 0.
Another question would be, what is your power-up sequence? Does SHDN goes before Vbatt is being provided in the system?
Also, it seems that you are trying to power-up the ADG1408 and ADG1404 at 3.3V. Please have a look at the Power Requirement Table of the Specifications Section of the respective datasheets, it is stated that the ADG1404/08 are operational from 5V to 16.5V in single supply rail. See figures below.
So if +VH = 3.3V only, it will not power-up the ADG1404 and ADG1408s.
You might want to have a look at these points too.