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DESCRIPTION
The WM8234 is a 16-bit analogue front end/digitiser IC
which processes and digitises the analogue output signals
from CCD sensors or Contact Image Sensors (CIS) at pixel
sample rates of up to 23MSPS.
The device has six analogue signal processing channels
each of which contains Reset Level Clamping, Correlated
Double Sampling (also Sample and Hold), Programmable
Gain, Automatic Gain Control (AGC) and Offset adjust
functions.
The output from each of these channels is time multiplexed,
in pairs, into two high-speed 16-bit Analogue to Digital
Converters. The digital data is available in a variety of
output formats via the flexible data port.
The WM8234 has a user selectable LVDS or CMOS output
architecture.
An internal 8-bit DAC is supplied for internal reference level
generation. This may be used during CDS to reference CIS
signals or during Clamping to clamp CCD signals. An
external reference level may also be supplied. ADC
references are generated internally, ensuring optimum
performance from the device.
A programmable automatic Black-Level Calibration function
is available to adjust the DC offset of the output data.
The WM8234 features a sensor timing clock generator for
both CCD and CIS sensors. The clock generator can accept
a slow or fast reference clock input and also has a flexible
timing adjustment function for output timing clocks to allow
use of many different sensors.
WM8234
70MSPS 6-Channel AFE with Sensor Timing Generation and
LVDS/CMOS Data Output
FEATURES
70MSPS conversion rate
16 bit ADC resolution
Current consumption – 280mA
3.3V single supply operation
Sample and hold /correlated double sampling
Programmable offset adjust (8-bit resolution)
Flexible clamp timing
Pixel clamp / line clamp mode
Programmable clamp voltage
Programmable CIS/CCD timing generator
Internally generated voltage references
Compliant for Spread Spectrum Clock
LVDS/CMOS output options
LVDS 5pair 490MHz 35-bit data
CMOS 90MHz output maximum
Complete on chip clock generator. MCLK 5MHz to 23MHz
Internal timing adjustment
Automatic Gain Control
Automatic Black Level Calibration
56-lead QFN package 7mm x 7mm
Serial control interface
APPLICATIONS
Digital copiers
USB2.0 compatible scanners
Multi-function peripherals
High-speed CCD/CIS sensor interface
WOLFSON MICROELECTRONICS plc
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Product Brief, February 2012, Rev 3.0
Copyright
2012
Wolfson Microelectronics plc.
WOLFSON [ WOLFSON MICROELECTRONICS PLC ]
