a error with ADG5412


    I use ADG5412 in my design, and I provide supply power with +/-18V(pin13 and pin4).

    But two of the four ADG5412 I used can not work correctly. When I provide the logic control pin with a high logic, the corresponding channel do not conduct signal. But the rest two can work correctly. When I test the GND pin(pin 5)of the two broken ADG5412, the avometer indict that the voltage of the pin is 5.6 volt and 4.9 volt accordingly, which should be 0 voltage in my design because I connect the GND pin to my AGND plane. Besides, the voltage of the rest two ADG5412 are all right.

What is the possible reason for my devices? Are they surely broken?