AN-731 APPLICATION NOTE introduces AD9985's automatic offset calibration feature. AD9985 is a pin-for-pin replacement of the AD9883A that includes an automatic offset calibration feature. It can self-adjust to eliminate any offset errors in its own ADC channels as well as any offset errors present on the incoming graphics or video signals.
The AD9985 is a pin-for-pin replacement for the AD9883A that includes an automatic offset calibration feature. This feature allows the device to self-adjust and eliminate offset errors in its ADC channels as well as any offset errors present on incoming graphics or video signals by monitoring the output during the back porch of input signals.
The document outlines register differences between the two devices, specifically highlighting new registers (0x16-0x1E) that control the Auto Offset function and changes to the functionality of offset registers (0x0B-0x0D) when the Auto Offset function is enabled. It provides instructions on how to activate the Auto Offset mode and program target codes for RGB or YPbPr signals.
The AD9985 is a pin-for-pin replacement of the AD9883A that includes an automatic offset calibration feature.
It monitors the output of each ADC during the back porch of the input signals to self-adjust and eliminate offset errors.
Any target code value between 1 and 254 can be set, though the specific offset range may not reach every value.