ZHCSCX2E January 2014 – October 2017 LM15851
PRODUCTION DATA.
In foreground mode the calibration process interrupts normal ADC operation and no output data is available during this time (the output code is forced to a static value). The calibration process should be repeated if the device temperature changes by more than 20ºC to ensure rated performance is maintained. Foreground calibration is initiated by setting the CAL_SFT bit (register 0x050, bit 3) which is self clearing. The foreground calibration process finishes within t(CAL) number of DEVCLK cycles. The process occurs somewhat longer when the timing calibration mode is enabled.
NOTE
Initiating a foreground calibration asynchronously resets the calibration control logic and may glitch internal device clocks. Therefore after setting the CAL_SFT bit clearing and then setting JESD_EN is necessary. If resetting the JESD204B link is undesirable for system reasons, background calibration mode may be preferred.