AD9643: Data value of zero volts input in invert mode

Question

Hello,

I have a question about the AD9643 data format from our customer.

Q. What value returns while inputting zero volts to VIN when using invert mode?

According to table 11 of the datasheet(rev.F), 0x2000 will return in normal mode.
The table 11 indicates the steps of the positive range is 0x0000 to 0x1FFF and the steps of the negative range is 0x2001 to 0x3FFF. The negative range is 0x1 smaller than the positive range.
So the customer expects it will return 0x1FFF while inputting zero volts to VIN when using invert mode.
Does AD9643 return 0x1FFF in invert mode?

Best regards,

y_suzuki

ADIApproved · Accepted Answer

Hi y_suzuki, 
 y_suzuki said: So the customer expects it will return 0x1FFF while inputting zero volts to VIN when using invert mode. 
 No, the device will return still 0x0000 if the input is zero volts using invert mode. 
 The positive range will be from 0x3FFF to 0x2001 while the negative range will be from 0x0001 to 0x2000. The invert mode is just the twos complement of the normal mode. 
 You can refer to the table attached below. 
 
 Regards, 
 Xavier)

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AD9643: Data value of zero volts input in invert mode

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