WM8148 Datasheet, PDF (1/43 Pages) Wolfson Microelectronics plc – 12-bit/12MSPS CCD/CIS Analogue Front End/Digitiser

WM8148
12-bit/12MSPS CCD/CIS Analogue Front End/Digitiser
Production Data, April 1999, Rev 4.0
DESCRIPTION
The WM8148 is a 12-bit, 12MSPS analogue front end/
digitiser IC, which interfaces to colour or monochrome linear
array CCDs or contact image sensors (CIS). The device
includes all the signal conditioning circuitry required to
process the analogue signals from the CCD or CIS prior to
the internal ADC.
Three signal-processing channels are included in the
device. Each channel features reset level clamping,
correlated double sampling (CDS), offset correction and
programmable gain amplification (PGA). The output signal
from each channel is then multiplexed into a high
performance 12-bit analogue to digital converter (ADC).
The reset level clamp and/or CDS functions can be selected
or bypassed depending on the application.
The WM8148 can be operated in several modes. The
operational mode of the device, including the sampling
scheme and power management is programmed via the
serial/parallel control interface.
Output data is presented in either 12-bit parallel or byte-
wide (8+4-bit) format.
FEATURES
• Correlated double sampling
• Programmable gain amplifier
• Programmable input clamp voltage
• Offset correction
• 12-bit, 12MSPS ADC
• Internal voltage reference
• 12-bit or 8+4 bit data output mode
• Single 5V supply or 5V analogue/3.3V digital supply
• Programmable sample timing
• Control interface compatible with previous Wolfson
AFEs
• 48-pin TQFP package
APPLICATIONS
• Flatbed scanners
• Document scanners
• Multi-function peripherals (MFPs)
• Colour copiers
• Character recognition systems
• Linear array CCDs
• Contact image sensors (CIS)
BLOCK DIAGRAM
RLC MCLK VSMP
(2)
(5) (7)
AVDD 1- 4
(41,28,27,3)
DVDD1-2
(1,13)
VRX VRB VRT
(32) (29) (31)
CL R_S V_S
TIMING CONTROL
VREF/BIAS
WM8148
RINP (36)
GINP (37)
BINP (39)
VRLC (33)
CDS
RLC
CDS
RLC
CDS
RLC
RLC ⁴
DAC
+
PGA
+
8
OFFSET
DAC
6
S C± AFLUEL ^L_..2
8
OFFSET
DAC
+
PGA
6
S C± AFLUEL ^L_..2
+
MUX
12-BIT
ADC
12/8
BIT
MUX
+
PGA
+
8
OFFSET
DAC
6
S C± AFLUEL ^L_..2
CONFIGURABLE
SERIAL/PARALLEL
CONTROL INTERFACE
(35,40,30,25,6)
AGND1 - 5
(8,24,4,26)
DGND1 - 4
(43) OEB
OP[11:0]
(9-12,14-21)
(48) PNS
(34) OVRD
(45) SDI/DNA
(46) SCK/RNW
(47) SEN/STB
(42) NRESET
(44) SDO
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 contain final
specifications current on publication date.
Supply of products conforms to Wolfson
Microelectronics' Terms and Conditions.
©1999 Wolfson Microelectronics Ltd.