Please see below a summary of my problem:
We have developed a data acquisition board based on DDC332C and are currently testing it for noise performance. The design parameters are as below:
CLK = 5Mhz, DCLK = 10Mhz, CONV = non continuous mode operation with side B integrated first, (with integration time: 100uS), VREF: 4.096 V, typical range is 6 / 7, output format 20bit.
We face missing code problems, The same missing codes were seen in Test mode of DDC332C.
I tried 2 devices total and 2 boards total , missing codes on the second board is the same as the first board. Pattern is every 14th sample is missing consecutive 4 times, followed by 13th sample.
I have verified that the problem is not caused by any other area of my design by observing waveform on DSO at the o/p of DDC232 (DOUT signal with reference to DCLK). It matches with the data read and sent to PC.
The missing code combinations are not there when 16 bit mode is used, since they fall at intervals of 13 and 14 codes.
I have tried all suggestions made by you (adjusting few cycle between DVALID and DCLK) and also tried different CLK, integration times etc but the same codes are missing. I hope to help for a solution soon. Even I tried in continuous mode operation also, behavior is same.
Thanks in advance
K.JHA
