XRD9826 Datasheet, PDF (9/33 Pages) Exar Corporation – 16-Bit Linear CIS/CCD Sensor Signal Processor with Serial Control

XRD9826
XRD9826
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 XRD9826 (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 XRD9826. Figure 4, is a diagram
of the XRD9826 in the external reference mode for CIS,
DC coupled applications.
Rev. 1.00
9