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... the analog plus compa
TM
EXAR Corporation 48720 Kato Road, Fremont, CA 94538 Phone (510)-668-7000, Fax (510)-668-7030
PRELIMINARY
4
RED
GRN
BLU
VDCEXT
VREF
+
DB7:0
DVDD
DGND
AVDD
AGND
ADCCLK
CLAMP
SYNCH
PG
A
TI
M
ING &
CO
NTRO
L LO
G
IC
AVD
D
6-
BIT
G
A
IN
R
E
G
IST
ER
S
12-
BIT
AD
C
RL
AG
N
D
DA
TA
I/O
PO
R
T
B
U
FFE
R
VR
T
VR
B
S/H
&
3-
1
MUX
8-
BIT
DAC
12
8
8-
BIT
O
F
F
SET
R
E
G
IST
ER
S
6
8
+
_
AG
N
D
V
DCRE
F
DC/A
C
IN
T
/EXT
_V
DCRE
F
CIS
/CCD
G
<
5:0>
O
<
7:0>
R
G
B
R
G
B
CLP
CLA
MP
Pow
e
r
Down
Pow
e
r
Down
VR
T
CCD
CIS
VBG
B
iasi
ng Ci
rcui
t for CA
NON
CIS
Figure 2. Simplified Functional Block Diagram of XRD9827
OPERATIONAL PROCEDURE
The routine listed below will first calibrate the photo response of the CIS using the XRD9827 by optimize
its offset and gain. After calibration, the XRD9827REF can be used to scan any color target to show CIS
non-color corrected response. (Color correction is typically done in the digital ASIC.)