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ADG1408

Question asked by Vita1iy on Dec 6, 2012
Latest reply on Dec 7, 2012 by Vita1iy

I used ADG1408 in the device which switches three differential inputs between 12 differential outputs (four channels for each input). In this way there are 6 ADG1408 chips and I use 4 output channels of each one, while remaining 4 channels are left unconnected. When I power on the device and choose the channel №1, the resistance between the input and corresponding output is about 4 Ohms (as specified in datasheet). The resistance between the input of channel 1 and output of channel 2 or 4 is several MOhms, but between the input of channel 1 and output of channel 3 it is 24 Ohms. The same situation takes place when I choose the channel №2, but between the input of channel 2 and the output of channel 4. All of 6 chips have the common informational inputs and all of them behave this way. The resistanse is low (24 Ohms) between channels 1 and 3 (when i choose one of them) and between channels 2 and 4 respectively. Could you help to understand such behaviour of ADG1408? The scheme of device is attached below.

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