LTC2497 Conversion

The LTC2497 is 16 Bits + Sign. B22-B6 are in two's complement format. For example Code 1010 0000 0000 0000 0000 0000 

B23 and B22 are 10. This indicates the output code is greater than or equal to 0 and less than full scale . Bits 22-6 are 0 1000 0000 0000 0000. This is equal to decimal +32768. 

A negative code example would be 0111 1111 1111 1111 1111 1111. B23 and B22 are 01. This indicates the output code is less than 0 and reater than or equal to -FS. Bits 22-6 are 1 1111 1111 1111 1111. this is equal to decimal -1.

Hi ghoover

Thanks for the promopt response. I tried the conversion...I still didnt get the result..did i missed anything?

I did quite a few data sets and all point to having a amplified digital value of 2.78-2.80.

Any possible error which might have caused this readings?

what is your reference voltage? Are you doing single-ended or differential measurement? Is the -input at ground or at vref/2? Decoding the input voltage of 0.507, assuming a 5V reference and the -input grounded, I come up with 0.5407V. That is in the ballpark. Remember +FS is only Vref/2. Can you provide a schematic or give more details? you might have a filter settling issue to account for the rest of the error.

1. Vref = Vss = 5v

2. Single ended

3. -ve Input = GND

I have attached the schematics below... Resistors: 0 ohms, I2C Res: 4.7k ohms, Caps = 0.1uF & 10uF

Thank you for helping.