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Wolfson Microelectronics plc |
WM8146
12-bit (8+4-bit) Linear Sensor Image Processor
Product Preview, January 2000 Rev 1.1
DESCRIPTION
The WM8146 is a 12-bit analogue front end/digitiser IC,
which processes and digitises the analogue output signals
from linear CCD sensors at pixel sample rates of up to
6MSPS.
The device includes three analogue signal processing
channels each of which contains Reset Level Clamping,
Correlated Double Sampling and Programmable Gain and
Offset adjust functions. The output from each of these
channels is time multiplexed into a single high-speed 12-bit
Analogue to Digital Converter. The digital output data is
available in 8+4-bit wide multiplexed format, with no missing
codes.
The WM8146 is controlled via a configurable serial
interface, which is compatible with all of Wolfson’s imaging
devices.
Powered from an analogue supply voltage of 5V and a
digital interface supply of either 5V or 3.3V, the WM8146
typically only consumes 175mW when operating from 5V
supplies.
FEATURES
• No missing codes guaranteed
• 6MSPS sample rate
• Colour pixel by pixel or line by line sampling
• Monochrome sampling
• Selectable reset level clamp voltage
• Pixel by pixel or line by line clamping
• Correlated double sampling
• 5-bit programmable gain amplifier
• 8-bit + sign offset adjustment
• 5V or 3.3V digital interface compatibility
• Serial control interface
• 28-pin SOIC package
APPLICATIONS
• Flatbed scanners
• Multi-function peripherals
• Copier scanners
• CCD sensor interfaces
BLOCK DIAGRAM
VRLC
(26)
AVDD VRT
(21) (24)
VRB
(23)
VMID AGND1 AGND2
(25) (22) (2)
VSMP MCLK
(5) (7)
RLC
(6)
DGND
(8)
DVDD1
(3)
DVDD2
(10)
VMID
RINP (1)
GINP(28)
BINP(27)
MUX
CL RS VS
S/H
S/H
CDS
PGA
5-BIT REG
S/H
S/H
CDS
PGA
5-BIT REG
S/H
S/H
CDS
PGA
5-BIT REG
TIMING CONTROL
OFFSET
++
8-BIT +
SIGN DAC
VMID
OFFSET
++
8-BIT +
SIGN DAC
VMID
OFFSET
++
8-BIT +
SIGN DAC
VMID
M
U
X
WM8146
12-bit
ADC
8+4
MUX
CONFIGURABLE
SERIAL CONTROL
INTERFACE
(4) OEB
(13) OP[0]
(14) OP[1]
(15) OP[2]
(16) OP[3]
(17) OP[4]
(18) OP[5]
(19) OP[6]
(20) OP[7]
(11)SDI
(12)SCK
(9) SEN
WOLFSON MICROELECTRONICS LTD
Lutton Court, Bernard Terrace, Edinburgh, EH8 9NX, UK
Tel: +44 (0) 131 667 9386
Fax: +44 (0) 131 667 5176
Email: [email protected]
http://www.wolfson.co.uk
Product Preview data sheets contain
specifications for products in the formative
phase of development. These products may
be changed or discontinued without notice.
1999 Wolfson Microelectronics Ltd.
WM8146
Product Preview
PIN CONFIGURATION
RINP
1
28 GINP
AGND2
2
27 BINP
DVDD1
3
26 VRLC
OEB
4
25 VMID
VSMP
5
24 VRT
RLC
6
23 VRB
MCLK
DGND
7
8
22 AGND1
WM8146
21 AVDD
SEN
9
20 OP[7]
DVDD2
10
19 OP[6]
SDI 11
18 OP[5]
SCK
12
17 OP[4]
OP[0]
13
16 OP[3]
OP[1]
14
15 OP[2]
ORDERING INFORMATION
DEVICE
XWM8146CDW/V
TEMP. RANGE
0 to 70oC
PACKAGE
28-pin SOIC
PIN DESCRIPTION
PIN NAME
TYPE
DESCRIPTION
1
RINP
Analogue input Red channel input video.
2 AGND2
Supply
Analogue ground (0V).
3 DVDD1
Supply
Digital supply (5V) for logic and clock generator. This must be operated at the same
potential as AVDD.
4
OEB
Digital input Output Hi-Z control, all digital outputs disabled when OEB = 1.
5
VSMP
Digital input Video sample synchronisation pulse.
6
RLC
Digital input Selects reset level clamp on a pixel-by-pixel basis – active high. Tie high to use on
every pixel.
7
MCLK
Digital input Master clock. This clock is applied at N times the input pixel rate (N = 2, 3, 6, 8 or
any multiple of 2 thereafter depending on input sample mode).
8 DGND
Supply
Digital ground (0V).
9
SEN
Digital input Enables the serial interface when high.
10 DVDD2
Supply
Digital supply (5V/3.3V), all digital I/O pins.
11 SDI Digital input Serial interface data input.
12 SCK Digital input Serial interface clock.
13
OP[0]
Digital output Digital multiplexed output data bus.
14
OP[1]
Digital output
15
OP[2]
Digital output OEB = 0: ADC output data is available in (8+4bit) multiplexed format on pins OP[7] to
16
OP[3]
Digital output OP[0]. See Operational Timing diagrams for details.
17
OP[4]
Digital output
OEB = 1: Output is Hi=Z.
18
OP[5]
Digital output
19
OP[6]
Digital output
20
OP[7]
Digital output
21 AVDD
Supply
Analogue supply (5V). This must be operated at the same potential as DVDD1.
22 AGND1
Supply
Analogue ground (0V).
23
VRB
Analogue output Lower reference point of ADC reference string
This pin must be connected to AGND via a decoupling capacitor.
24
VRT
Analogue output Upper reference point of ADC reference string
This pin must be connected to AGND via a decoupling capacitor.
25
VMID
Analogue output Buffered mid-point of ADC reference string
This pin must be connected to AGND via a decoupling capacitor.
26
VRLC
Analogue output Selectable analogue output voltage for RLC.
This pin must be connected to AGND via a decoupling capacitor.
27
BINP
Analogue input Blue channel input video.
28
GINP
Analogue input Green channel input video.
WOLFSON MICROELECTRONICS LTD
PP Rev 1.1 January 2000
2
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