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DESCRIPTION
The WM8150 is a 12-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 8MSPS.
The device includes a complete analogue signal processing
channel containing Reset Level Clamping, Correlated
Double Sampling, Programmable Gain and Offset adjust
functions. Internal multiplexers allow fast switching of offset
and gain for line-by-line colour processing. The output from
this channel is time multiplexed into a high-speed 12-bit
Analogue to Digital Converter. The digital output data is
available in 4-bit wide multiplexed format.
An internal 4-bit DAC is supplied for internal reference level
generation. This may be used to reference CIS signals or
during Reset Level Clamping to clamp CCD signals. An
external reference level may also be supplied. ADC
references are generated internally, ensuring optimum
performance from the device.
Using an analogue supply voltage of 5V, a digital core
voltage of 5V, and a digital interface supply of either 5V or
3.3V, the WM8150 typically only consumes 160mW when
operating from a single 5V supply.
WM8150
Single Channel 12-bit CIS/CCD AFE with 4-bit Wide Output
FEATURES
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12-bit ADC
8MSPS conversion rate
Low power - 170mW typical
5V single supply or 5V/3.3V dual supply operation
Single channel operation
Correlated double sampling
Programmable gain (8-bit resolution)
Programmable offset adjust (8-bit resolution)
Programmable clamp voltage
4-bit wide multiplexed data output format
Internally generated voltage references
20-pin SSOP package
Serial control interface
APPLICATIONS
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Flatbed and sheetfeed scanners
USB compatible scanners
Multi-function peripherals
High-performance CCD sensor interface
BLOCK DIAGRAM
VSMP
MCLK
AVDD
DVDD1
DVDD2
VRT VRX VRB
CL
R
S
V
S
TIMING CONTROL
VREF/BIAS
R
M
G
U
X
B
8
OFFSET
DAC
+
PGA
8
VINP
RLC
CDS
+
I/P SIGNAL
POLARITY
ADJUST
12-
BIT
ADC
DATA
I/O
PORT
OP[0]
OP[1]
OP[2]
OP[3]/SDO
VRLC/VBIAS
R
G
B
M
U
X
W
WM8150
RLC
DAC
4
CONFIGURABLE
SERIAL
CONTROL
INTERFACE
SEN
SCK
SDI
AGND1
AGND2
DGND
WOLFSON MICROELECTRONICS plc
w :www.wolfsonmicro.com
Production Data, February 2005, Rev 4.1
Copyright
2005
Wolfson Microelectronics plc