Preliminary W6662CF
SCANNER ANALOG FRONT END
1. GENERAL DESCRIPTION
The W6662 is a highly integrated CCD/CIS analog front end signal processor. It provides the
components required for all necessary front-end signal process of a CCD/CIS scanner, including a 3-
channel input clamp circuit for correlated double sampling (short as CDS) mode, a multiplexer to mux
3-channel inputs to a correlated double sampling (CDS) circuit, a programmable offset adjusted and
gain controlled amplifier, a 12-bit analog-to-digital converter.
CDS or S&H (sample and hold) of operation modes can be chosen. The device configuration is
programmed via 3-wire or 4-wired interface, operation modes, offset and gain value of each channel
can be programmed.
2. FEATURES
• 12-bit A/D Converter
• No Missing Code Guaranteed
• Three channels analog input with clamp circuit individually
• Integrated Correlated Double Sampler (CDS)
• Supports Contact Image Sensors (CIS)
• Accept CCD/CIS sensor with three channel or single channel analog out
• External offset voltage input for CIS reference voltage
• Built-in bandgap reference circuit for CDS mode and A/D Converter
• Integrated 6-bit Programmable Gain Amplifier (PGA) with 3-channel register selected
• Integrated 8-bit offset adjustment with 3-channel register selected
• 3 MHz sampling rate of offset/gain adjustment circuit
• Three-wired or four-wired Serial Interface programmable
• Registers readback capability
• Low power CMOS device
• Power down mode supported
• 3/5V digital I/O pin
• Packageed in 48-pin QFP
Applications:
Flatbed Scanners
Sheetfeed Scanners
Film Scanners
Publication Release Date: December 1998
-1-
Revision A1