AnsweredAssumed Answered

AD7768 evaluation board output coding

Question asked by Terumasa on Oct 16, 2017
Latest reply on Oct 17, 2017 by Terumasa

Hello

 

Our customer uses AD7768 evaluation board then ,

it is seemed that the result of ADC is not 2's complement but offset binary.

Output coding of AD7768 is 2's complement only in datasheet .

Is this software issue ?

Could you teach me how to set 2's complement  ?

 

Attachment is its result ( input 0~0.5V)

He inputs 0~0.5V  to Ain+ pin  and GNS is connected to AIN- pin.

Analog voltage is correct but  LSB is not correct.

MAX: 0.49V  , 9400273LSB

MIN: 0.001V, 8.3908 E+6

Pk-Pk:  0.49V, 1009469LSB  ( about 490nV/LSB and this value is correct)

 

another attached file  input 0 ~-0.5 V is input  0~0.5V to AIN-pin and GND to AIN+pin.

 

Register is not changed and remains default setting ( check AIN1  only).

 

Regards,

Terumasa

Outcomes