Question about VDDB pin of ADG3123

Question

Hello, This is Kwonjoon Lee from South Korea. I would like to ask about the VDDB pin of the ADG3123. 
 (Detailed Question) 
 1. We would like to use only first 6 channels (A1-A6 and Y1-Y6), and we will not utilize other 2 channels (A7-A8 and Y7-Y8). In this case, could we apply 14V and 0V to the VDDA pin and the VDDB pin, respectively? 
 Best regards, Kwonjoon Lee

Christian · Accepted Answer

Hi KwonjoonLee ,

This setup is not possible as this will violate the device's absolute maximum ratings and may cause permanent damage.

The product datasheet mentions that the VDDA ≤ VDDB. The voltage between VDDB to VSS and VDDB to GND is 10.8 V minimum. Tying the VDDB to GND breaks the condition.

I suggest tying the VDDB to the VDDA and being mindful of the power supply sequence. It is a good practice to power up the VDDA and VSS before applying signals to its inputs (VDDA and A1 to A8).

Best regards,
Christian

Electronic Design Services - PartnerZone

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Question about VDDB pin of ADG3123