XRD9827 Datasheet, PDF (13/32 Pages) Exar Corporation – 12-Bit Linear CIS/CCD Sensor Signal Processor with Serial Control

XRD9827
XRD9827
C ^{REXT CEXT}
I
S
RED
N/C
N/C
M
U
N/C
X
CLAMP
RINT
VDD
VRT
R
L
VRB
Figure 7. CIS AC Coupled Application
This value corresponds to the black reference of the
image sensor. When the CLAMP pin is set back to low,
the ADC samples the video signal with respect to the
black reference. The typical value for the external
capacitor is 100pF. This value should be adjusted
according to the time constant (Tc) needed in a particu-
lar application. The CLAMP pin has an internal 150 ohm
impedance (R ) which is in series with the external
INT
capacitor (C_EXT).
Therefore, Tc =1/R_INTC_EXT
If the input to the external capacitor has a source
impedance (R_EXT), then:
T_c=1/(R_INT+R_EXT)C_EXT
Rev. 1.20
13