I use the ADG1408 for select one resistor which links to the circuit. The 8 channels are with diffirent resistors link to Vref, such as 1k,10k,100k,1m,10m,100m. The problem is that when I choose the channels which is with resistor greater than 1m, the circuit does not works properly. At this moment, the voltage divided between the choosed resistor and the resistor Rx is wrong. I use DMM test the resistor between any two channnels of ADG1408, and I found that there is only 200kΩ between any two channels. Is this problem caused by small resistance between the channels ? Or other selector can be used to complete this feature?