ZHCSIZ1G May 2010 – November 2018 LM98640QML-SP
PRODUCTION DATA.
In CDS mode, both the Reference Level and Video Level are presented to the LM98640QML-SP on the OSX– pin. The OSX+ pin should be bypassed to ground with a 0.1-µF capacitor. The CLAMP pulse is then used to sample the Reference Level and the SAMPLE pulse is used to sample the Video Level. The output code will then be the Reference Level minus the Video Level, or the difference between the Reference Level and Video Level. A minimum code represents zero deviation between the Reference and Video Levels and a maximum code represents a 2-V deviation between the Reference and Video Levels with CDS and PGA gains of 1x.
To place the LM98640QML-SP in CDS Mode from power up, first write the baseline configuration to the registers as shown in Table 5. Then ensure S/H mode is disabled by clearing bit[7] of the Sample & Hold Register (0x06), then enable CDS mode by setting bit[0] of the Main Configuration Register (0x00). Next the CLAMP and SAMPLE pulses need to be positioned correctly over the reference and video levels respectively using the CLAMP/SAMPLE Adjust.