XRD98L23 Datasheet, PDF (13/32 Pages) Exar Corporation – 8-Bit, High-speed Linear CIS/CCD Sensor Signal Processor with Serial Control

XRD98L23
XRD98L23
C
I
REXT CEXT
RED
S
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 180 ohm
(from electrical tabels) impedance (R ) which is in
INT
series with the external capacitor (C_EXT).
Therefore, Tc =1/R_INTC_EXT
If the input to the external capacitor has a source
impedance (R_EXT), then:
T =1/(R +R )C
c
INT EXT EXT
Rev. 1.00
13