XRD9825 Datasheet, PDF (9/33 Pages) Exar Corporation – 16-Bit Linear CIS/CCD Sensor Signal Processor with Serial Control

XRD9825
XRD9825
C _RED
I
M
S
N/C
N/C
U
N/C
X
VDD
VRT
RL
VRB
Figure 3. Application with Offset in the Range (-100mv to 500mv)
The input is added to VRB before the signal passes
through the ADC. If the CIS output is zero, then the
output of the ADC will be zero code. This enables the
CIS to be referenced to the bottom ladder reference
voltage to use the full range of the ADC.
Some CIS sensors have an output with an offset voltage
of greater than 500mV. If the CIS output is beyond the
offset range of the XRD9825 (see Offset Control DAC,
Pg. 22) set the internal mode registers to external
reference. An external reference voltage equal to the
value of the CIS offset voltage can be applied to
VDCEXT (Figure 4) in order to meet the dynamic range
of the XRD9825. Figure 4, is a diagram of the XRD9825
in the external reference mode for CIS, DC coupled
applications.
Rev. 1.00
9