WM8141 Datasheet, PDF (1/31 Pages) Wolfson Microelectronics plc – 12-bit 6MSPS CIS/CCD Analogue Front End/Digitiser

WM8141
12-bit 6MSPS CIS/CCD Analogue Front End/Digitiser
Production Data, October 2000, Rev 3.0
DESCRIPTION
The WM8141 is a 12-bit analogue front end/digitiser that
processes and digitises the analogue output signals from
CCDs or Contact Image Sensors (CIS). The device can be
operated as either a three channel or a single channel
device at pixel sample rates of up to 6MSPS. The device
has both external and programmable internal black level
reference options for CIS operation. The WM8141 runs off a
single supply voltage of either 3.3V or 5V. Alternatively, the
device can be operated from split 5V core and 3.3V digital
interface supplies.
The WM8141 includes three analogue signal processing
channels each of which contains reset level clamping,
correlated double sampling and programmable offset and
gain adjust facilities. Each of these channels is time
multiplexed into a single high-speed 12-bit resolution ADC,
which digitises the pixel image information. The digital data
output is available to the user in either 12-bit parallel or
8/6/4-bit wide multiplexed formats.
The internal control registers are programmable via a
convenient serial or parallel digital interface. The WM8141
typically consumes only 45mA and less than 10µA when in
power down mode.
FEATURES
• 12-bit resolution ADC
• 6MSPS conversion rate at 5V supply
• 5V or 3.3V single supply or 5V/3.3V dual supply operation
• Single or 3 channel operation
• Correlated double sampling
• Programmable gain (8-bit resolution)
• Programmable offset adjust (8-bit resolution)
• 12-bit parallel or 8/6/4-bit wide multiplexed output bus
• Internally generated voltage references
• External or internal reference for CIS operation
• Low power – 225mW typical at 5V supply
• Interface and timing compatible with WM8143, WM8144
and WM8142 devices
• Drop in replacement for WM8143-12
• 32-pin TQFP package
APPLICATIONS
• Flatbed and sheetfeed scanners
• USB compatible scanners
• Multi-function peripherals
• CCD sensor interface
• Contact image sensor (CIS) interface
BLOCK DIAGRAM
VRLC/VBIAS
(18)
VSMP MCLK
(27) (28)
AVDD DVDD1 DVDD2
(12) (14) (32)
VRT VRX VRB
(16) (17) (15)
RINP (21)
GINP (20)
BINP (19)
CL
RLC
RLC
R_S
M
U
X
V_S
TIMING CONTROL
CDS
R_{M 8}
GU
X
B
OFFSET
DAC
+ PGA
VREF/BIAS
R_M
GU
X
B
I/P SIGNAL
8
POLARITY
ADJUST
CDS
+ PGA
8
OFFSET
DAC
8
I/P SIGNAL
POLARITY
ADJUST
+
M
+U
X
WM8141
(22) OEB
12
BIT
ADC
DATA
I/O
PORT
(30) OP[0]
(31) OP[1]
(1) OP[2]
(2) OP[3]
(3) OP[4]
(4) OP[5]
(5) OP[6]
(6) OP[7]
(7) OP[8]
(8) OP[9]
(9) OP[10]
(10) OP[11]/SDO
RLC
RLC ₄
DAC
CDS
+ PGA
+
8
OFFSET
DAC
8
I/P SIGNAL
POLARITY
ADJUST
CONFIGURABLE
SERIAL/
PARALLEL
CONTROL
INTERFACE
(23) SEN/STB
(25) SCK/RNW
(24) SDI/DNA
(26) RLC/ACYC
(11) NRESET
(13)
AGND
(29)
DGND
WOLFSON MICROELECTRONICS LTD
Lutton Court, Bernard Terrace, Edinburgh, EH8 9NX, UK
Tel: [phone]
Fax: [phone]
Email: [e-mail]
http://www.wolfson.co.uk
Production Data Datasheets contain final
specifications current on publication date.
Supply of products conforms to Wolfson
Microelectronics’ Terms and Conditions.
2000 Wolfson Microelectronics Ltd.