Exar Corporation 48720 Kato Road, Fremont CA, 94538 • (510) 668-7000 • FAX (510) 668-7017 • www.exar.com
xrxr XRD9818
3-CHANNEL 16-BIT LINEAR CCD/CIS SENSOR SIGNAL PROCESSOR
JUNE 2004 REV. 1.0.1
GENERAL DESCRIPTION
The XRD9818 is a fully integrated, high-performance
analog signal processor/digitizer specifically
designed for use in 3-channel/2-channel/1-channel
CCD/CIS document imaging applications.
Each channel of the XRD9818 includes a Correlated
Double Sampler (CDS), Offset adjustment,
Programmable Gain Amplifier (PGA). After the gain
and offset adjustments the analog inputs are
sequentially sampled and digitized by a 16-bit A/D
converter. The digital output data is available in 8 or
4-bit wide multiplexed format.
The analog front-end can be configured for use in
CCD or CIS data acquisition applications. The CDS
mode of operation supports both line and pixel-clamp
modes and can be used to achieve significant
reduction in system 1/f noise and CCD reset clock
feed-through. Five programmable clamp levels are
available in CCD mode to adjust for CCD signal swing
and reset pulse size. For CIS mode there are 3
selectable reference options, two internally generated
and one external applied reference.
Two PGA ranges, programmable through the serial
port, help interface the XRD9818 to CCD imagers
that have either a 3V or 2V output swings. The range
of 1x to 5x is used for 3V inputs and the range of 1.5x
to 7.5x is used for 2V inputs. Each channel has an
offset range of -180mV to 180mV (1.4mV/step) for
fine adjustment and an additional -100mV to 200mV
(100mV/step) of gross offset adjustment to correct for
any system offsets.
FEATURES
• 16-Bit A/D Converter
• Triple-Channel, 4MSPS Color Scan Mode
• Single-Channel, 8MSPS Monochrome Scan Mode
• Multiplexed 8-Bit or 4-Bit Output Data Formats
• Triple Correlated Double Sampler
• Triple 9-Bit Programmable Gain Amplifier
• Two Programmable Gain Ranges
• Triple 10-Bit Offset Compensation DAC
• -280mV to +380mV Offset Compensation
• 28-pin TSSOP Package
• Internal Voltage Reference
• 3V Operation with 5V Tolerant inputs
• Low Power CMOS: 190mW @ 3.3V (typ), Power
Down 1mW (typ)
APPLICATIONS
• 48-Bit Color Scanners
• High-performance CCD or CIS Color Scanners
• Multifunction Peripherals
• Film Scanners
