I am using the AD7766 ADC for designing a circuit.I have used a single ended to differential driver at its source to convert signals to +-5V.
But when I run the SPI code for interfacing with the ADC I seem to only get the first 12bits as a constant value.The remaining 12 bits are just changing randomly.
Vref for ADC is 5V.
My Vdrive = 2.5V
DVDD = 2.5 V
AVDD = 2.5 V
Mclk is 1MhZ oscillator
Sclk I have tried all frequencies(from 100kHz upto 6MHz)Still no luck.
I also checked on the DSO,the SDO line gives only data12 bits.The remaining bits are just noise.
So that expains why I am getting 12bits on my SPI interface.
But what is the reason for getting only 12bit data.
Please find attached below the schematic.