Hi There,
I have a couple questions about the ADC12DJ3200 calibration when used in single-channel mode:
1) How sample rate dependent are the factory-trimmed calibration value? Ex, if the calibration values are calculated for 3200 MS/s and I run the device at 2667 MHz, should I be expected to change specific calibration values? The timing adjust values come to mind. Are these values updated when a foreground calibration is performed?
2) Do you have any reference code to read/write data from the CAL_DATA register? I performed a foreground cal and then read data from the CAL_DATA register, following the instructions in the datasheet: Set CAL_DATA_EN to 1 but I left ADDR_HOLD = 0 for simplicity and then I read from the CAL_DATA register 673 times, storing the values in an array. As a test, I repeated the Calibration data read process expecting to read the same values that I had previously read but this wasn't the case. I am able to read specific calibration registers, for example register GAIN_TRIM A (0x07A), repeatedly and get the same result after each read. Is there a workaround, such as reading all the calibration registers documented on page 93 of the datasheet (registers 0x60 through 0xFF) and caching those?
3) Does TI expect calibration values to be valid from one power cycle to another? Assuming I am able to get the CAL_DATA functionality to work, if I perform a cal and save the values somewhere, would I expect to be able to reprogram the ADC with the same calibration values and have good performance, assuming the ambient environment is the same?
Thanks!
-Sean
