WM8195_05 [WOLFSON]
14-bit 12MSPS CIS/CCD Analogue Front End/Digitiser; 14位12MSPS CIS / CCD模拟前端/数字转换器
| 型号： | WM8195_05 |
| 厂家： | 
WOLFSON MICROELECTRONICS PLC |
| 描述： | 14-bit 12MSPS CIS/CCD Analogue Front End/Digitiser |
| 文件： | 总33页 (文件大小：374K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
WM8195
w
14-bit 12MSPS CIS/CCD Analogue Front End/Digitiser
DESCRIPTION
FEATURES
•
•
•
•
•
•
•
•
•
•
•
14-bit ADC
The WM8195 is a 14-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 12MSPS.
No missing codes guaranteed
12MSPS conversion rate
Low power – 210mW typical
5V single supply or 5V/3.3V dual supply operation
Single or 3 channel operation
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. Three multiplexers allow single
channel processing. The output from each of these
channels is time multiplexed into a single high-speed 14-bit
analogue-to-digital converter. The digital output data is
available in 14-bit parallel or 8, 7 or 4-bit wide multiplexed
format, with no missing codes.
Correlated double sampling
Programmable gain (8-bit resolution)
Programmable offset adjust (8-bit resolution)
Programmable clamp voltage
14-bit parallel or 8, 7 or 4-bit wide multiplexed data output
formats
Internally generated voltage references
48-lead TQFP package
Serial or parallel control interface
•
•
•
An internal 4-bit DAC is supplied for internal reference level
generation. This may be used during CDS to reference CIS
signals or during Reset Level Clamping to clamp CCD
signals. Alternatively an external reference level may be
applied. ADC references are generated internally, ensuring
optimum performance from the device.
APPLICATIONS
•
•
•
•
Flatbed and sheetfeed scanners
USB compatible scanners
Multi-function peripherals
High-performance CCD sensor interface
Using an analogue supply voltage of 5V and a digital
interface supply of either 5V or 3.3V, the WM8195 typically
only consumes 210mW when operating from a single 5V
supply and less than 20µA when in power down mode.
BLOCK DIAGRAM
VSMP MCLK
AVDD1-2
VRX VRB
VRT
VRLC/VBIAS
DVDD1-3
w
WM8195
CL
RS VS
TIMING CONTROL
VREF/BIAS
R
G
B
M
U
X
8
OFFSET
DAC
OEB
OP[0]
OP[1]
OP[2]
OP[3]
OP[4]
OP[5]
OP[6]
OP[7]
OP[8]
OP[9]
OP[10]
OP[11]
OP[12]
OP[13]/SDO
RINP
RLC
RLC
CDS
CDS
PGA
+
+
+
+
M
U
X
I/P SIGNAL
POLARITY
ADJUST
R
G
B
8
M
U
X
DATA
I/O
PORT
M
U
X
14-
BIT
ADC
GINP
BINP
PGA
8
OFFSET
DAC
8
I/P SIGNAL
POLARITY
ADJUST
RLC
PGA
+
CDS
+
8
OFFSET
DAC
8
I/P SIGNAL
POLARITY
ADJUST
SEN/STB
SCK/RNW
SDI/DNA
RLC/ACYC
NRESET
CONFIGURABLE
SERIAL/
PARALLEL
CONTROL
RLC
DAC
4
INTERFACE
AGND1-6
DGND1-5
Production Data July 2005 Rev 4.1
WOLFSON MICROELECTRONICS plc
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Copyright 2005 Wolfson Microelectronics plc.
WM8195
Production Data
TABLE OF CONTENTS
DESCRIPTION .......................................................................................................1
FEATURES.............................................................................................................1
APPLICATIONS .....................................................................................................1
BLOCK DIAGRAM .................................................................................................1
TABLE OF CONTENTS .........................................................................................2
PIN CONFIGURATION...........................................................................................3
ORDERING INFORMATION ..................................................................................3
PIN DESCRIPTION ................................................................................................4
ABSOLUTE MAXIMUM RATINGS.........................................................................6
RECOMMENDED OPERATING CONDITIONS .....................................................6
ELECTRICAL CHARACTERISTICS ......................................................................7
INPUT VIDEO SAMPLING............................................................................................... 9
OUTPUT DATA TIMING .................................................................................................. 9
SERIAL INTERFACE..................................................................................................... 11
PARALLEL INTERFACE......................................................................................12
INTRODUCTION ........................................................................................................... 13
INPUT SAMPLING......................................................................................................... 13
RESET LEVEL CLAMPING (RLC) ................................................................................. 13
CDS/NON-CDS PROCESSING ..................................................................................... 14
OFFSET ADJUST AND PROGRAMMABLE GAIN......................................................... 15
ADC INPUT BLACK LEVEL ADJUST ............................................................................ 16
OVERALL SIGNAL FLOW SUMMARY .......................................................................... 16
CALCULATING OUTPUT FOR ANY GIVEN INPUT...................................................... 17
OUTPUT FORMATS...................................................................................................... 18
CONTROL INTERFACE ................................................................................................ 19
TIMING REQUIREMENTS............................................................................................. 20
PROGRAMMABLE VSMP DETECT CIRCUIT ............................................................... 21
REFERENCES............................................................................................................... 21
POWER SUPPLY .......................................................................................................... 22
POWER MANAGEMENT............................................................................................... 22
LINE-BY-LINE OPERATION.......................................................................................... 22
OPERATING MODES.................................................................................................... 24
OPERATING MODE TIMING DIAGRAMS..................................................................... 25
DEVICE CONFIGURATION .................................................................................27
REGISTER MAP............................................................................................................ 27
REGISTER MAP DESCRIPTION................................................................................... 28
RECOMMENDED EXTERNAL COMPONENTS ..................................................31
PACKAGE DIMENSIONS ....................................................................................32
IMPORTANT NOTICE..........................................................................................33
ADDRESS:..................................................................................................................... 33
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WM8195
PIN CONFIGURATION
48 47 46 45 44 43 42 41 40 39 38 37
36
VRX
VRLC/VBIAS
AGND1
1
2
DGND4
DVDD3
OP[10]
OP[9]
35
34
33
32
31
30
29
28
27
26
25
3
BINP
4
AGND2
GINP
5
OP[8]
6
OP[7]
AGND3
RINP
7
DGND3
OP[6]
8
AGND4
DVDD1
OEB
9
OP[5]
OP[4]
10
11
12
OP[3]
SEN/STB
DGND2
19
13 14 15 16 17 18
20 21 22 23 24
ORDERING INFORMATION
TEMPERATURE
MOISTURE
SENSITIVITY LEVEL
PEAK SOLDERING
TEMPERATURE
DEVICE
RANGE
PACKAGE
48-lead TQFP
1mm thick body
XWM8195SCFT/V
XWM81955CFT/RV
0 to 70°C
0 to 70°C
MSL2
MSL2
260oC
(Pb-free)
48-lead TQFP
1mm thick body
260oC
(Pb-free, tape and
reel)
Note:
Reel quantity = 2,200
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Production Data
PIN DESCRIPTION
PIN
NAME
TYPE
Analogue output Input return bias voltage.
This pin must be decoupled to AGND via a capacitor.
Selectable analogue output voltage for RLC or single-ended bias reference.
DESCRIPTION
1
VRX
2
VRLC/VBIAS
Analogue I/O
This pin would typically be decoupled to AGND via a capacitor.
VRLC can be externally driven if programmed Hi-Z.
3
4
AGND1
BINP
Supply
Analogue input
Supply
Analogue ground (0V).
Blue channel input video.
Analogue ground (0V).
Green channel input video.
Analogue ground (0V).
Red channel input video.
Analogue ground (0V).
5
AGND2
GINP
6
Analogue input
Supply
7
AGND3
RINP
8
Analogue input
Supply
9
AGND4
DVDD1
10
Supply
Digital supply (5V) for logic and clock generator. This must be operated at the same
potential as AVDD.
11
12
OEB
Digital input
Digital input
Output Hi-Z control, all digital outputs disabled when OEB = 1.
SEN/STB
Serial interface: enable pulse, active high
Parallel interface: strobe, active low
Latched on NRESET rising edge: if Low then device control is via serial interface,
if high then device control is via parallel interface.
13
14
SDI/DNA
Digital input
Digital input
Serial interface: serial input data signal
Parallel interface:
High = data, Low = address
SCK/RNW
Serial interface: serial clock signal
Parallel interface:
High: OP[13:6] is output bus.
Low: OP[13:6] is input bus (Hi-Z).
15
16
VSMP
Digital input
Digital input
Video sample synchronisation pulse.
RLC/ACYC
RLC (active high) selects reset level
clamp on a pixel-by-pixel basis – tie high
if used on every pixel.
ACYC autocycles between R, G, B
inputs when in Line-by-Line mode.
17
MCLK
Digital input
Supply
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).
18
19
20
21
22
23
DGND1
NC
Digital ground (0V).
No connection.
NC
No connection.
OP[0]
OP[1]
OP[2]
Digital output
Digital output
Digital output
Pins OP[13:0] form a Hi-Z digital bi-directional bus. There are several modes:
Hi-Z: when OEB = 1.
14-bit output: 14-bit data is output on OP[13:0].
8-bit multiplexed output: data is output on OP[13:6] at 2 ADC conversion rate.
7-bit multiplexed output: data is output on OP[13:6] at 2 ADC conversion rate.
4-bit multiplexed output: data is output on OP[13:10] at 4 ADC conversion rate.
See Output Formats section in Device Description for further details.
Input 8-bit: control data is input on OP[13:6] in parallel mode when SCK/RNW = 0,
and SEN/STB = 0.
Output 8-bit: register read back data is output in parallel on OP[13:6] when
SCK/RNW = 1, and SEN/STB = 0, or in serial on pin SDO when SEN/STB = 1.
24
25
26
27
28
29
30
DVDD2
DGND2
OP[3]
Supply
Supply
Digital I/O supply (3.3V/5V).
Digital ground (0V).
Digital output
Digital output
Digital output
Digital I/O
Supply
See pins 21 to 23 for details.
OP[4]
OP[5]
OP[6]
DGND3
Digital ground (0V).
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WM8195
PIN
31
32
33
34
35
36
37
38
39
NAME
TYPE
DESCRIPTION
OP[7]
OP[8]
Digital I/O
Digital I/O
Digital I/O
Digital I/O
Supply
See pins 21 to 23 for details.
OP[9]
OP[10]
DVDD3
DGND4
OP[11]
Digital I/O supply (3.3V/5V).
Digital ground (0V).
Supply
Digital I/O
Digital I/O
Digital I/O
See pins 21 to 23 for details.
If the device has been configured to use the serial interface, pin OP[13]/SDO may
be used to output register read-back data when OEB = 0 and SEN has been
pulsed high.
OP[12]
OP[13]/SDO
See Serial Interface sections in Device Description for further details.
40
41
42
DGND5
NC
Supply
Digital ground (0V).
No connection.
NRESET
Digital input
Reset input, active low. This signal forces a reset of all internal registers and selects
whether the serial or parallel control interface is used. See pin SEN/STB.
43
44
45
46
47
48
AVDD1
AVDD2
AGND5
AGND6
VRB
Supply
Supply
Supply
Supply
Analogue supply (5V).
Analogue supply (5V).
Analogue ground (0V).
Analogue ground (0V).
Analogue output Lower reference voltage. This pin must be capacitively decoupled to AGND.
Analogue output Lower reference voltage. This pin must be capacitively decoupled to AGND.
VRT
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WM8195
Production Data
ABSOLUTE MAXIMUM RATINGS
Absolute Maximum Ratings are stress ratings only. Permanent damage to the device may be caused by continuously operating at
or beyond these limits. Device functional operating limits and guaranteed performance specifications are given under Electrical
Characteristics at the test conditions specified.
ESD Sensitive Device. This device is manufactured on a CMOS process. It is therefore generically susceptible
to damage from excessive static voltages. Proper ESD precautions must be taken during handling and storage
of this device.
Wolfson tests its package types according to IPC/JEDEC J-STD-020B for Moisture Sensitivity to determine acceptable storage
conditions prior to surface mount assembly. These levels are:
MSL1 = unlimited floor life at <30°C / 85% Relative Humidity. Not normally stored in moisture barrier bag.
MSL2 = out of bag storage for 1 year at <30°C / 60% Relative Humidity. Supplied in moisture barrier bag.
MSL3 = out of bag storage for 168 hours at <30°C / 60% Relative Humidity. Supplied in moisture barrier bag.
The Moisture Sensitivity Level for each package type is specified in Ordering Information.
CONDITION
MIN
MAX
Analogue supply voltages: AVDD1, 2
Digital supply voltages: DVDD1 − 3
Digital grounds: DGND1 − 5
Analogue grounds: AGND1 − 6
Digital inputs, digital outputs and digital I/O pins
Analogue inputs (RINP, GINP, BINP)
Other pins
GND - 0.3V
GND - 0.3V
GND - 0.3V
GND - 0.3V
GND - 0.3V
GND - 0.3V
GND - 0.3V
GND + 7V
GND + 7V
GND + 0.3V
GND + 0.3V
DVDD2 + 0.3V
AVDD + 0.3V
AVDD + 0.3V
°
°
Operating temperature range: TA
Storage temperature
0 C
+70 C
°
°
-65 C
+150 C
Notes:
1. GND denotes the voltage of any ground pin.
2. AGND1 − 6 and DGND1 − 5 pins are intended to be operated at the same potential. Differential voltages
between these pins will degrade performance.
RECOMMENDED OPERATING CONDITIONS
CONDITION
SYMBOL
TA
MIN
0
TYP
MAX
70
UNITS
Operating temperature range
Analogue supply voltage
Digital core supply voltage
Digital I/O supply voltage
°C
V
AVDD1, 2
DVDD1
4.75
4.75
5.0
5.0
5.25
5.25
V
5V I/O
DVDD2, 3
DVDD2, 3
4.75
2.97
5.0
3.3
5.25
3.63
V
V
3.3V I/O
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WM8195
ELECTRICAL CHARACTERISTICS
Test Conditions
AVDD1 = AVDD2 = DVDD1 = DVDD2 = DVDD3 =4.75 to 5.25V, AGND = DGND = 0V, TA = 0 to 70°C, MCLK = 24MHz unless
otherwise stated.
PARAMETER
SYMBOL
TEST
MIN
TYP
MAX
UNIT
CONDITIONS
Overall System Specification (including 14-bit ADC, PGA, Offset and CDS functions)
NO MISSING CODES GUARANTEED
Conversion rate
12
0.4
MSPS
Vp-p
Vp-p
V
Full-scale input voltage range
(see Note 1)
Max Gain
Min Gain
4.08
Input signal limits (see Note 2)
Full-scale transition error
VIN
0
AVDD
Gain = 0dB;
PGA[7:0] = 4B(hex)
20
20
mV
Zero-scale transition error
Gain = 0dB;
mV
PGA[7:0] = 4B(hex)
Differential non-linearity
Integral non-linearity
DNL
INL
1.25
LSB
LSB
8
1
1
3
Channel to channel gain matching
Total output noise
%
Min Gain
Max Gain
LSB rms
LSB rms
References
Upper reference voltage
VRT
VRB
VRX
VRTB
2.85
1.35
1.65
1.5
V
V
V
V
Ω
Lower reference voltage
Input return bias voltage
Diff. reference voltage (VRT-VRB)
Output resistance VRT, VRB, VRX
VRLC/Reset-Level Clamp (RLC)
RLC switching impedance
VRLC short-circuit current
VRLC output resistance
1.4
1.6
1
50
5
Ω
mA
Ω
2
VRLC Hi-Z leakage current
RLCDAC resolution
VRLC = 0 to AVDD
1
µA
4
bits
V/step
V/step
V
RLCDAC step size, RLCDAC = 0
RLCDAC step size, RLCDAC = 1
VRLCSTEP
VRLCSTEP
VRLCBOT
0.25
0.17
0.39
RLCDAC output voltage at
code 0(hex), RLCDACRNG = 0
RLCDAC output voltage at
code 0(hex), RLCDACRNG = 1
VRLCBOT
VRLCTOP
VRLCTOP
0.26
4.16
2.81
V
V
RLCDAC output voltage at
code F(hex) RLCDACRNG, = 0
RLCDAC output voltage at
V
code F(hex), RLCDACRNG = 1
VRLC deviation
-50
+50
mV
Offset DAC, Monotonicity Guaranteed
Resolution
8
bits
LSB
Differential non-linearity
Integral non-linearity
Step size
DNL
INL
0.1
0.5
1
0.25
2.04
-260
+260
LSB
mV/step
mV
Output voltage
Code 00(hex)
Code FF(hex)
mV
Notes:
1.
2.
Full-scale input voltage denotes the maximum amplitude of the input signal at the specified gain.
Input signal limits are the limits within which the full-scale input voltage signal must lie.
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WM8195
Production Data
Test Conditions
AVDD1 = AVDD2 = DVDD1 = DVDD2 = DVDD3 =4.75 to 5.25V, AGND = DGND = 0V, TA = 0 to 70°C, MCLK = 24MHz unless
otherwise stated.
PARAMETER
SYMBOL
TEST
MIN
TYP
MAX
UNIT
CONDITIONS
Programmable Gain Amplifier
Resolution
Gain
8
208
bits
V/V
283 − PGA[7 : 0]
Max gain, each channel
Min gain, each channel
Gain error, each channel
Analogue to Digital Converter
Resolution
GMAX
GMIN
7.4
0.74
1
V/V
V/V
%
14
12
3
bits
MSPS
V
Speed
Full-scale input range
(2*(VRT-VRB))
DIGITAL SPECIFICATIONS
Digital Inputs
High level input voltage
Low level input voltage
High level input current
Low level input current
Input capacitance
VIH
VIL
IIH
IIL
0.8 DVDD2/3
V
0.2 DVDD2/3
V
1
1
µA
µA
pF
CI
5
Digital Outputs
High level output voltage
Low level output voltage
High impedance output current
Digital IO Pins
VOH
VOL
IOZ
IOH = 1mA
IOL = 1mA
DVDD2/3 - 0.5
V
V
0.5
1
µA
Applied high level input voltage
Applied low level input voltage
High level output voltage
Low level output voltage
Low level input current
High level input current
Input capacitance
VIH
VIL
VOH
VOL
IIL
0.8 DVDD2/3
DVDD2/3 - 0.5
V
V
0.2 DVDD2/3
IOH = 1mA
IOL = 1mA
V
0.5
1
V
µA
µA
pF
µA
IIH
1
CI
5
High impedance output current
Supply Currents
IOZ
1
Total supply current − active
(Three channel mode)
Total supply current − active
(Single channel mode)
42
35
65
mA
mA
MCLK = 24MHz
LINEBYLINE = 1
MCLK = 24MHz
Total analogue supply current −
active (Three channel mode)
IAVDD
IAVDD
37
30
mA
mA
MCLK = 24MHz
Total analogue supply current −
active (One channel mode)
LINEBYLINE = 1
MCLK = 24MHz
Digital core supply current,
DVDD1 − active (Note1)
3
2
mA
mA
µA
MCLK = 24MHz
MCLK = 24MHz
Digital I/O supply current, DVDD2
− active (Note1)
Supply current − full power down
20
60
mode
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WM8195
INPUT VIDEO SAMPLING
tPER
tMCLKH tMCLKL
MCLK
tVSMPSU
tVSMPH
VSMP
INPUT
tVSU
tVH
tRSU
tRH
VIDEO
Figure 1 Input Video Timing
Test Conditions
AVDD1 = AVDD2 = DVDD1 = DVDD2 = DVDD3 =4.75 to 5.25V, AGND = DGND = 0V, TA = 0 to 70°C, MCLK = 24MHz
unless otherwise stated.
PARAMETER
SYMBOL
TEST CONDITIONS
MIN
TYP
MAX
UNITS
MCLK period
tPER
41.6
ns
MCLK high period
MCLK low period
VSMP set-up time
VSMP hold time
tMCLKH
tMCLKL
tVSMPSU
tVSMPH
tVSU
18.8
18.8
6
ns
ns
ns
ns
ns
ns
ns
ns
3
Video level set-up time
Video level hold time
Reset level set-up time
Reset level hold time
Notes:
10
3
tVH
tRSU
10
3
tRH
1.
2.
t
VSU and tRSU denote the set-up time required after the input video signal has settled.
Parameters are measured at 50% of the rising/falling edge.
OUTPUT DATA TIMING
MCLK
tPD
OP[13:0]
Figure 2 Output Data Timing
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Production Data
OEB
tPZE
tPEZ
OP[13:0]
Hi-Z
Hi-Z
Figure 3 Output Data Enable Timing
Test Conditions
AVDD1 = AVDD2 = DVDD1 = DVDD2 = DVDD3 =4.75 to 5.25V, AGND = DGND = 0V, TA = 0 to 70°C, MCLK = 24MHz
unless otherwise stated.
PARAMETER
SYMBOL
tPD
TEST CONDITIONS
MIN
TYP
MAX
40
UNITS
ns
Output propagation delay
Output enable time
Output disable time
IOH = 1mA, IOL = 1mA
tPZE
20
ns
tPEZ
15
ns
MCLK
tACYCSU
tACYCH
tACYCH
tACYCSU
RLC/ACYC
PGA/OFFSET
MUX OUTPUT
Figure 4 Auto Cycle Timing
Test Conditions
AVDD = DVDD1 = 4.75 to 5.25V, DVDD2 = 2.97 to 3.63V, AGND = DGND = 0V, TA = 0 to 70°C, MCLK = 32MHz unless
otherwise stated.
PARAMETER
SYMBOL
tACYCSU
tACYCH
TEST CONDITIONS
MIN
6
TYP
MAX
UNITS
ns
Auto Cycle set-up time
Auto Cycle hold time
3
ns
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WM8195
SERIAL INTERFACE
tSPER
tSCKL tSCKH
SCK
tSSU
tSH
SDI
SEN
SDO
tSCE
tSEW tSEC
tSCRDZ
tSERD
tSCRD
ADC
DATA
ADC DATA
MSB
LSB
REGISTER DATA
Figure 5 Serial Interface Timing
Test Conditions
AVDD1 = AVDD2 = DVDD1 = DVDD2 = DVDD3 =4.75 to 5.25V, AGND = DGND = 0V, TA = 0 to 70°C, MCLK = 24MHz
unless otherwise stated.
PARAMETER
SYMBOL
TEST CONDITIONS
MIN
TYP
MAX
UNITS
SCK period
tSPER
41.6
ns
SCK high
tSCKH
tSCKL
tSSU
18.8
18.8
6
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
SCK low
SDI set-up time
SDI hold time
tSH
6
SCK to SEN set-up time
SEN to SCK set-up time
SEN pulse width
tSCE
12
12
25
tSEC
tSEW
tSERD
tSCRD
tSCADC
SEN low to SDO = Register data
SCK low to SDO = Register data
SCK low to SDO = ADC data
30
30
30
Note: Parameters are measured at 50% of the rising/falling edge.
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Production Data
PARALLEL INTERFACE
tSTB
STB
tASU
Hi-Z
tAH
tDH
tSTAO
tSTDO
tDSU
Hi-Z
ADC DATA OUT
ADDRESS IN
DATA IN
ADC DATA OUT
REG. DATA OUT
ADC DATA OUT
OP[13:6]
tADLS
tADLH
tADHS
tADHH
DNA
tOPZ
tOPD
RNW
Figure 6 Parallel Interface Timing
Test Conditions
AVDD1 = AVDD2 = DVDD1 = DVDD2 = DVDD3 =4.75 to 5.25V, AGND = DGND = 0V, TA = 0 to 70°C, MCLK = 24MHz
unless otherwise stated.
PARAMETER
SYMBOL
TEST CONDITIONS
MIN
TYP
MAX
UNITS
RNW low to OP[13:6] Hi-Z
tOPZ
10
ns
Address set-up time to STB low
DNA low set-up time to STB low
Strobe low time
tASU
tADLS
tSTB
0
5
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
30
5
Address hold time from STB high
DNA low hold time from STB high
Data set-up time to STB low
DNA high set-up time to STB low
Data hold time from STB high
Data high hold time from STB high
RNW high to OP[13:6] output
tAH
tADLH
tDSU
tADHS
tDH
5
0
5
5
tADHH
tOPD
tSTDO
5
30
30
Data output propogation delay from
STB low
ADC data out propogation delay
from STB high
tSTAO
30
ns
Note: Parameters are measured at 50% of the rising/falling edge.
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WM8195
DEVICE DESCRIPTION
INTRODUCTION
A block diagram of the device showing the signal path is presented on Page 1.
The WM8195 samples up to three inputs (RINP, GINP and BINP) simultaneously. The device then
processes the sampled video signal with respect to the video reset level or an internally/externally
generated reference level using either one or three processing channels.
Each processing channel consists of an Input Sampling block with optional Reset Level Clamping
(RLC) and Correlated Double Sampling (CDS), a 8-bit programmable offset DAC and an 8-bit
Programmable Gain Amplifier (PGA).
The ADC then converts each resulting analogue signal to a 14-bit digital word. The digital output from
the ADC is presented on a 14-bit wide bus, with optional 8+6-bit, 7+7-bit or 4+4+4+2-bit multiplexed
formats.
On-chip control registers determine the configuration of the device, including the offsets and gains
applied to each channel. These registers are programmable via a serial or parallel interface.
INPUT SAMPLING
The WM8195 can sample and process one to three inputs through one or three processing channels
as follows:
Colour Pixel-by-Pixel: The three inputs (RINP, GINP and BINP) are simultaneously sampled for
each pixel and a separate channel processes each input. The signals are then multiplexed into the
ADC, which converts all three inputs within the pixel period.
Monochrome: A single chosen input (RINP, GINP, or BINP) is sampled, processed by the
corresponding channel, and converted by the ADC. The choice of input and channel can be changed
via the control interface, e.g. on a line-by-line basis if required.
Colour Line-by-Line: A single chosen input (RINP, GINP, or BINP) is sampled and multiplexed into
the red channel for processing before being converted by the ADC. The input selected can be
switched in turn (RINP → GINP → BINP → RINP…) together with the PGA and offset DAC control
registers by pulsing the RLC/ACYC pin. This is known as auto-cycling. Alternatively, other sampling
sequences can be generated via the control registers. This mode causes the blue and green
channels to be powered down. Refer to the Line-by-Line Operation section for more details.
RESET LEVEL CLAMPING (RLC)
To ensure that the signal applied to the WM8195 lies within its input range (0V to AVDD) the CCD
output signal is usually level shifted by coupling through a capacitor, CIN. The RLC circuit clamps the
WM8195 side of this capacitor to a suitable voltage during the CCD reset period.
A typical input configuration is shown in Figure 7 An internal clamp pulse, CL, is generated from
MCLK and VSMP by the Timing Control Block. When CL is active the voltage on the WM8195 side of
CIN, at RINP, is forced to the VRLC/VBIAS voltage (VVRLC) by closing of switch 1. When the CL pulse
turns off, switch 1 opens, the voltage at RINP initially remains at VVRLC but any subsequent variation
in sensor voltage (from reset to video level) will couple through CIN to RINP.
RLC is compatible with both CDS and non-CDS operating modes, as selected by switch 2. Refer to
the CDS/Non-CDS Processing section.
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RLC/ACYC MCLK VSMP
TIMING CONTROL
FROM CONTROL
INTERFACE
CL
RS
VS
CIN
S/H
+
-
TO OFFSET DAC
+
RINP
2
S/H
1
RLC
CDS
INPUT SAMPLING
BLOCK FOR RED
CHANNEL
EXTERNAL VRLC
CDS
VRLC/
VBIAS
4-BIT
RLC DAC
FROM CONTROL
INTERFACE
VRLCEXT
Figure 7 Reset Level Clamping and CDS Circuitry
If auto-cycling is not required, RLC can be selected pixel-by-pixel by pin RLC/ACYC. Figure 8
illustrates control of RLC for a typical CCD waveform, with CL applied during the reset period.
The input signal applied to the RLC/ACYC pin is sampled on the positive edge of MCLK that occurs
during each VSMP pulse. The sampled level, high (or low) controls the presence (or absence) of the
internal CL pulse on the next reset level. The position of CL can be adjusted by using control bits
CDSREF[1:0] (Figure 9).
If auto-cycling is required, pin RLC/ACYC is no longer available for this function and control bit
RLCINT determines whether clamping is applied.
MCLK
VSMP
ACYC/RLC
or RLCINT
1
X
X
0
X
X
0
Programmable Delay
CL
(CDSREF = 01)
INPUT VIDEO
RGB
RGB
RGB
RLC on this Pixel
No RLC on this Pixel
Figure 8 Relationship of RLC Pin, MCLK and VSMP to Internal Clamp Pulse, CL
The VRLC/VBIAS pin can be driven internally by a 4-bit DAC (RLCDAC) by writing to control bits
RLCV[3:0]. The RLCDAC range and step size may be increased by writing to control bit
RLCDACRNG. Alternatively, the VRLC/VBIAS pin can be driven externally by writing to control bit
VRLCEXT to disable the RLCDAC and then applying a d.c. voltage to the pin.
CDS/NON-CDS PROCESSING
For CCD type input signals, the signal may be processed using CDS, which will remove pixel-by-pixel
common mode noise. For CDS operation, the video level is processed with respect to the video reset
level, regardless of whether RLC has been performed. To sample using CDS, control bit CDS must
be set to 1 (default), this sets switch 2 into the position shown in (Figure 7) and causes the signal
reference to come from the video reset level. The time at which the reset level is sampled, by clock
Rs/CL, is adjustable by programming control bits CDSREF[1:0], as shown in Figure 9.
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WM8195
MCLK
VSMP
VS
RS/CL (CDSREF = 00)
RS/CL (CDSREF = 01)
RS/CL (CDSREF = 10)
RS/CL (CDSREF = 11)
Figure 9 Reset Sample and Clamp Timing
For CIS type sensor signals, non-CDS processing is used. In this case, the video level is processed
with respect to the voltage on pin VRLC/VBIAS, generated internally or externally as described
above. The VRLC/VBIAS pin is sampled by Rs at the same time as Vs samples the video level in
this mode; non-CDS processing is achieved by setting switch 2 in the lower position. CDS = 0.
OFFSET ADJUST AND PROGRAMMABLE GAIN
The output from the CDS block is a differential signal, which is added to the output of an 8-bit Offset
DAC to compensate for offsets and then amplified by an 8-bit PGA. The gain and offset for each
channel are independently programmable by writing to control bits DAC[7:0] and PGA[7:0].
The gain characteristic of the WM8195 PGA is shown in Figure 10. Figure 11 shows the maximum
device input voltage that can be gained up to match the ADC full-scale input range (3V).
8
7
6
5
4
3
2
1
0
4.5
4
3.5
3
2.5
2
1.5
1
0.5
0
0
64
128
192
256
0
64
128
192
256
Gain register value (PGA[7:0])
Gain register value (PGA[7:0])
Figure 10 PGA Gain Characteristic
Figure 11 Peak Input Voltage to Match ADC Full-scale Range
In colour line-by-line mode the gain and offset coefficients for each colour can be multiplexed in order
(Red → Green → Blue → Red…) by pulsing the ACYC/RLC pin, or controlled via the FME,
ACYCNRLC and INTM[1:0] bits. Refer to the Line-by-Line Operation section for more details.
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ADC INPUT BLACK LEVEL ADJUST
The output from the PGA should be offset to match the full-scale range of the ADC (3V). For
negative-going input video signals, a black level (zero differential) output from the PGA should be
offset to the top of the ADC range by setting register bits PGAFS[1:0]=10. For positive going input
signal the black level should be offset to the bottom of the ADC range by setting PGAFS[1:0]=11.
Bipolar input video is accommodated by setting PGAFS[1:0]=00 or PGAFS[1:0]=01 (zero differential
input voltage gives mid-range ADC output).
OVERALL SIGNAL FLOW SUMMARY
Figure 12 represents the processing of the video signal through the WM8195.
OUTPUT
INVERT
BLOCK
INPUT
SAMPLING
BLOCK
OFFSET DAC PGA
ADC BLOCK
BLOCK
BLOCK
D2
x (16383/VFS
if PGAFS[1:0]=11
)
V1
V2
V3
D1
+0
X
+16383 if PGAFS[1:0]=10
+8191 if PGAFS[1:0]=0x
OP[13:0]
+
+
VIN
digital
analog
+
-
CDS = 1
CDS = 0
D2 = D1 if INVOP = 0
D2 = 16383-D1 if INVOP = 1
VRESET
PGA gain
A = 208/(283-PGA[7:0])
VVRLC
Offset
DAC
260mV*(DAC[7:0]-127.5)/127.5
VIN is RINP or GINP or BINP
VRESET is VIN sampled during reset clamp
VRLC is voltage applied to VRLC pin
RLCEXT=1
RLCEXT=0
V
CDS, RLCEXT,RLCV[3:0], DAC[7:0],
PGA[7:0], PGAFS[1:0] and INVOP are set
by programming internal control registers.
CDS = 1 for CDS, 0 for non-CDS
RLC
DAC
VRLCSTEP*RLCV[3:0] + VRLCBOT
Figure 12 Overall Signal Flow
The INPUT SAMPLING BLOCK produces an effective input voltage V1. For CDS, this is the
difference between the input video level VIN and the input reset level VRESET. For non-CDS this is the
difference between the input video level VIN and the voltage on the VRLC/VBIAS pin, VVRLC
optionally set via the RLC DAC.
,
The OFFSET DAC BLOCK then adds the amount of fine offset adjustment required to move the
black level of the input signal towards 0V, producing V2.
The PGA BLOCK then amplifies the white level of the input signal to maximise the ADC range,
outputting voltage V3.
The ADC BLOCK then converts the analogue signal, V3, to a 14-bit unsigned digital output, D1.
The digital output is then inverted, if required, through the OUTPUT INVERT BLOCK to produce D2.
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WM8195
CALCULATING OUTPUT FOR ANY GIVEN INPUT
The following equations describe the processing of the video and reset level signals though
the WM8199. The values of V1 V2 and V3 are often calculated in reverse order during device
setup. The PGA value is written first to set tshe input Voltage range, the Offset DAC is then
adjusted to compensate for any Black/Reset level offsets and finally the RLC DAC value is
set to position the reset level correctly during operation.
Note: Refer to WAN0123 for detailed information on device calibration procedures.
The following equations describe the processing of the video and reset level signals through
the WM8195.
INPUT SAMPLING BLOCK: INPUT SAMPLING AND REFERENCING
If CDS = 1, (CDS operation) the previously sampled reset level, VRESET, is subtracted from the input
video.
V1
=
VIN - VRESET ................................................................... Eqn. 1
If CDS = 0, (non-CDS operation) the simultaneously sampled voltage on pin VRLC is subtracted
instead.
V1
=
VIN - VVRLC .................................................................... Eqn. 2
If RLCEXT = 1, VVRLC is an externally applied voltage on pin VRLC/VBIAS.
If RLCEXT = 0, VVRLC is the output from the internal RLC DAC.
VVRLC
=
(VRLCSTEP RLCV[3:0]) + VRLCBOT ................................. Eqn. 3
V
RLCSTEP is the step size of the RLC DAC and VRLCBOT is the minimum output of the RLC DAC.
OFFSET DAC BLOCK: OFFSET (BLACK-LEVEL) ADJUST
The resultant signal V1 is added to the offset DAC output.
V2
=
V1 + {260mV (DAC[7:0]-127.5) } / 127.5 ..................... Eqn. 4
PGA NODE: GAIN ADJUST
The signal is then multiplied by the PGA gain,
V3
=
V2 208/(283- PGA[7:0]) .............................................. Eqn. 5
ADC BLOCK: ANALOGUE-DIGITAL CONVERSION
The analogue signal is then converted to a 14-bit unsigned number, with input range configured by
PGAFS[1:0].
D1[13:0] = INT{ (V3 /VFS
D1[13:0] = INT{ (V3 /VFS
D1[13:0] = INT{ (V3 /VFS
)
)
)
16383} + 8191 PGAFS[1:0] = 00 or 01 ...... Eqn. 6
16383} PGAFS[1:0] = 11 ............... Eqn. 7
16383} + 16383 PGAFS[1:0] = 10 ............... Eqn. 8
where the ADC full-scale range, VFS = 3V.
OUTPUT INVERT BLOCK: POLARITY ADJUST
The polarity of the digital output may be inverted by control bit INVOP.
D2[13:0] = D1[13:0]
(INVOP = 0) ...................... Eqn. 9
(INVOP = 1) ...................... Eqn. 10
D2[13:0] = 16383 – D1[13:0]
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OUTPUT FORMATS
The digital data output from the ADC is available to the user in either 14-bit parallel or 8/7/4-bit wide
multiplexed formats by setting control bits MUXOP[1:0]. Latency of valid output data with respect to
VSMP is programmable by writing to control bits DEL[1:0]. The latency for each mode is shown in the
Operating Mode Timing Diagrams section.
Figure 13 shows the output data formats for Modes 1 – 2 and 4 – 6. Figure 14 shows the output data
formats for Mode 3. Table 1 summarises the output data obtained for each format.
MCLK
MCLK
14-BIT PARALLEL
OUTPUT
14-BIT PARALLEL
OUTPUT
A
A
8+6 AND 7+7-BIT
OUTPUT
8+6 AND 7+7-BIT
OUTPUT
A
B
A
B
4+4+4+2-BIT
OUTPUT
4+4+4+2-BIT
OUTPUT
A
B
C
D
A B A B C D
Figure 13 Output Data Formats
Figure 14 Output Data Formats
(Mode 3)
(Modes 1 − 2, 4 − 6)
OUTPUT
FORMAT
MUXOP[1:0]
OUTPUT
PINS
OUTPUT
14-bit parallel
00
01
10
OP[13:0]
A = d13, d12, d11, d10, d9, d8, d7, d6, d5, d4, d3,
d2, d1, d0
8+6-bit
multiplexed
OP[13:6]
OP[13:6]
A = d13, d12, d11, d10, d9, d8, d7, d6
B = d5, d4, d3, d2, d1, d0, CC, OVRNG
7+7-bit
A = d13, d12, d11, d10, d9, d8, d7, CC
B = d6, d5, d4, d3, d2, d1, d0, OVRNG
4+4+4+2-bit
(nibble)
11
OP[13:10]
A = d13, d12, d11, d10
B = d9, d8, d7, d6
C = d5, d4, d3, d2
D = d1, d0, CC, OVRNG
Table 1 Details of Output Data Shown in Figure 13 and Figure 14.
FLAGS
The following flags are output during multiplexed modes:
CC can be used in colour modes 1 and 5 to identify the green channel output, from which the blue
and red data can be identified.
INPUT
RINP
GINP
BINP
CC
0
1
0
Table 2 Input Sampled Flags CC[1:0]
OVRNG indicates that the current output data was produced by an input signal that exceeded the
input range limit of the device. 1 = out of range, 0 = within range.
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CONTROL INTERFACE
The internal control registers are programmable via the serial or parallel digital control interface. The
register contents can be read back via the parallel interface on pins OP[13:6], or via the serial
interface on pin OP[13]/SDO.
Note: It is recommended that a software reset is carried out after the power-up sequence, before
writing to any other register. This ensures that all registers are set to their default values (as shown
in Table 6).
SERIAL INTERFACE: REGISTER WRITE
Figure 15 shows register writing in serial mode. Three pins, SCK, SDI and SEN are used. A six-bit
address (a5, 0, a3, a2, a1, a0) is clocked in through SDI, MSB first, followed by an eight-bit data
word (b7, b6, b5, b4, b3, b2, b1, b0), also MSB first. Each bit is latched on the rising edge of SCK.
When the data has been shifted into the device, a pulse is applied to SEN to transfer the data to the
appropriate internal register. Note all valid registers have address bit a4 equal to 0 in write mode.
SCK
a5
0
a3
a2
a1
a0
b7
b6
b5
b4
b3
b2
b1
b0
SDI
Address
Data Word
SEN
Figure 15 Serial Interface Register Write
Using the serial interface, a software reset is carried out by writing to Address “000100” with any
value of data (i.e. Data Word = XXXXXXXX).
SERIAL INTERFACE: REGISTER READ-BACK
Figure 16 shows register read-back in serial mode. Read-back is initiated by writing to the serial bus
as described above but with address bit a4 set to 1, followed by an 8-bit dummy data word. Writing
address (a5, 1, a3, a2, a1, a0) will cause the contents (d7, d6, d5, d4, d3, d2, d1, d0) of
corresponding register (a5, 0, a3, a2, a1, a0) to be output MSB first on pin SDO (on the falling edge
of SCK). Note that pin SDO is shared with an output pin, OP[13], therefore OEB should always be
held low when register read-back data is expected on this pin. The next word may be read in to SDI
while the previous word is still being output on SDO.
SCK
a5
1
a3 a2 a1 a0
x
x
x
x
x
x
x
x
SDI
Address
Data Word
SEN
SDO/
d7 d6 d5 d4 d3 d2 d1 d0
OP[13]
Output Data Word
OEB
Figure 16 Serial Interface Register Read-back
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PARALLEL INTERFACE: REGISTER WRITE
Figure 17 shows register write in parallel mode. The parallel interface uses bits OP[13:6] of the
output bus and the STB, DNA and RNW pins. Pin RNW must be low during a write operation. The
DNA pin defines whether the data byte is address (low) or data (high). The 6-bit address (a5, 0, a3,
a2, a1, a0) is input into OP[11:6], LSB into OP[6], (OP[12] and OP[13] are ignored) when DNA is low,
then the 8-bit data word is input into OP[13:6], LSB into OP[6], when DNA is high. The data bus
OP[13:6] for both address and data is clocked in on the falling edge of STB. Note all valid registers
have address bit a4 equal to 0.
STB
Driven Externally
Driven by AFE
Driven by AFE
Hi-Z
Hi-Z
Normal Output Data
Normal Output Data
Address
Data
OP[13:6]
DNA
RNW
Figure 17 Parallel Interface Register Write
Using the parallel interface, a software reset is carried out by writing “000100” to OP[13:8] when
RNW and DNA are low. Any value of data can be written for this address when DNA changes to high
(i.e. Data = XXXXXXXX on OP[15:8]).
PARALLEL INTERFACE: REGISTER READ-BACK
Figure 18 shows register read-back in parallel mode. Read-back is initiated by writing the 6-bit
address (a5, 1, a3, a2, a1, a0) into OP[11:6] by pulsing the STB pin low. Note that a4 = 1 and pins
RNW and DNA are low. When RNW and DNA are high and STB is strobed again, the contents (d7,
d6, d5, d4, d3, d2, d1, d0) of the corresponding register (a5, 0, a3, a2, a1, a0) will be output on
OP[13:6], LSB on pin OP[6]. Until STB is pulsed low, the current contents of the ADC (shown as
Normal Output Data) will be present on OP[13:6]. Note that the register data becomes available on
the output data pins so OEB should be held low when read-back data is expected.
STB
Driven by AFE
Driven by AFE
Driven Externally
Address
Hi-Z
Hi-Z
Normal Output Data
Normal Output Data
OP[13:6]
DNA
Read Data
RNW
Figure 18 Parallel Interface Register Read-back
TIMING REQUIREMENTS
To use this device a master clock (MCLK) of up to 24MHz and a per-pixel synchronisation clock
(VSMP) of up to 12MHz are required. These clocks drive a timing control block, which produces
internal signals to control the sampling of the video signal. MCLK to VSMP ratios and maximum
sample rates for the various modes are shown in Table 5.
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PROGRAMMABLE VSMP DETECT CIRCUIT
The VSMP input is used to determine the sampling point and frequency of the WM8195. Under
normal operation a pulse of 1 MCLK period should be applied to VSMP at the desired sampling
frequency (as shown in the Operating Mode Timing Diagrams) and the input sample will be taken on
the first rising MCLK edge after VSMP has gone low. However, in certain applications such a signal
may not be readily available. The programmable VSMP detect circuit in the WM8195 allows the
sampling point to be derived from any signal of the correct frequency, such as a CCD shift register
clock, when applied to the VSMP pin.
When enabled, by setting the VSMPDET control bit, the circuit detects either a rising or falling edge
(determined by POSNNEG control bit) on the VSMP input pin and generates an internal VSMP pulse.
This pulse can optionally be delayed by a number of MCLK periods, specified by the VDEL[2:0] bits.
Figure 19 shows the internal VSMP pulses that can be generated by this circuit for a typical clock
input signal. The internal VSMP pulse is then applied to the timing control block in place of the
normal VSMP pulse provided from the input pin. The sampling point then occurs on the first rising
MCLK edge after this internal VSMP pulse, as shown in the Operating Mode Timing Diagrams.
MCLK
INPUT
PINS
VSMP
POSNNEG = 1
VS
VS
VS
(VDEL = 000) INTVSMP
(VDEL = 001) INTVSMP
(VDEL = 010) INTVSMP
(VDEL = 011) INTVSMP
(VDEL = 100) INTVSMP
(VDEL = 101) INTVSMP
(VDEL = 110) INTVSMP
(VDEL = 111) INTVSMP
VS
VS
VS
VS
VS
VS
VS
VS
VS
VS
VS
VS
VS
VS
VS
VS
VS
VS
VS
VS
VS
POSNNEG = 0
(VDEL = 000) INTVSMP
(VDEL = 001) INTVSMP
(VDEL = 010) INTVSMP
(VDEL = 011) INTVSMP
(VDEL = 100) INTVSMP
(VDEL = 101) INTVSMP
(VDEL = 110) INTVSMP
(VDEL = 111) INTVSMP
VS
VS
VS
VS
VS
VS
VS
VS
VS
VS
VS
VS
VS
VS
VS
VS
VS
VS
VS
VS
VS
VS
VS
VS
Figure 19 Internal VSMP Pulses Generated by Programmable VSMP Detect Circuit
REFERENCES
The ADC reference voltages are derived from an internal bandgap reference, and buffered to pins
VRT and VRB, where they must be decoupled to ground. Pin VRX is driven by a similar buffer, and
also requires decoupling. The output buffer from the RLCDAC also requires decoupling at pin
VRLC/VBIAS.
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POWER SUPPLY
The WM8195 can run from a 5V single supply or from split 5V (core) and 3.3V (digital interface)
supplies.
POWER MANAGEMENT
Power management for the device is performed via the Control Interface. The device can be powered
on or off completely by setting the EN bit and SELPD bit low. Alternatively, when control bit SELPD is
high, only blocks selected by further control bits (SELDIS[3:0]) are powered down. This allows the
user to optimise power dissipation in certain modes, or to define an intermediate standby mode to
allow a quicker recovery into a fully active state. In Line-by-Line operation, the green and blue
channel PGAs are automatically powered down.
All the internal registers maintain their previously programmed value in power down modes and the
control interface inputs remain active. Table 3 summarises the power down control bit functions.
EN
0
SELDPD
0
0
1
Device completely powers down.
1
Device completely powers up.
X
Blocks with respective SELDIS[3:0] bit high are disabled.
Table 3 Power Down Control
LINE-BY-LINE OPERATION
Certain linear sensors (e.g. Contact Image Sensors) give colour output on a line-by-line basis. i.e. a
full line of red pixels followed by a line of green pixels followed by a line of blue pixels. In order to
accommodate this type of signal the WM8195 can be set into Monochrome mode, with the input
channel switched by writing to control bits CHAN[1:0] between every line. Alternatively, the WM8195
can be placed into colour line-by-line mode by setting the LINEBYLINE control bit. When this bit is
set the green and blue processing channels are powered down and the device is forced internally to
only operate in MONO mode (because only one colour is sampled at a time) through the red channel.
Figure 20 shows the signal path when operating in colour line-by-line mode.
VRLC/VBIAS
VSMP
MCLK
CL
RS VS TIMING CONTROL
R
8
OFFSET
MUX
OFFSET
DAC
G
B
14-
BIT
ADC
DATA
I/O
PORT
RINP
RLC
RLC
RLC
CDS
+
PGA
8
+
OP[13:0]
INPUT
MUX
R
I/P SIGNAL
POLARITY
ADJUST
PGA
MUX
G
GINP
BINP
B
SEN/STB
SCK/RNW
SDI/DNA
RLC/ACYC
NRESET
CONFIGURABLE
SERIAL/
PARALLEL
CONTROL
RLC
DAC
4
INTERFACE
Figure 20 Signal Path When in Line-by-Line Mode
In this mode the input multiplexer and (optionally) the PGA/Offset register multiplexers can be auto-
cycled by the application of pulses to the RLC/ACYC input pin by setting the ACYCNRLC register bit.
See Figure 4 for detailed timing information. The multiplexers change on the first MCLK rising edge
after RLC/ACYC is taken high. A write to the auto-cycle reset register causes these multiplexers to
be reset; selecting the RINP pin and the RED offset/gain registers. Alternatively, all three
multiplexers can be controlled via the serial interface by writing to register bits INTM[1:0] to select the
desired colour. It is also possible for the input multiplexer to be controlled separately from the PGA
and Offset multiplexers. Table 4 describes all the multiplexer selection modes that are possible.
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WM8195
FME ACYCNRLC
NAME
Internal,
no force mux
DESCRIPTION
0
0
1
0
1
0
Input mux, offset and gain registers determined by
internal register bits INTM1, INTM0.
Auto-cycling,
no force mux
Input mux, offset and gain registers auto-cycled, RINP
→ GINP → BINP → RINP… on RLC/ACYC pulse.
Internal,
Input mux selected from internal register bits FM1, FM0;
force mux
Offset and gain registers selected from internal register
bits INTM1, INTM0.
1
1
Auto-cycling,
force mux
Input mux selected from internal register bits FM1, FM0;
Offset and gain registers auto-cycled, RED → GREEN
→ BLUE → RED… on RLC/ACYC pulse.
Table 4 Colour Selection Description in Line-by-Line Mode
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OPERATING MODES
Table 5 summarises the most commonly used modes, the clock waveforms required and the register
contents required for CDS and non-CDS operation.
MODE
DESCRIPTION
CDS
MAX
SENSOR
INTERFACE
DESCRIPTION
TIMING
REQUIRE-
MENTS
REGISTER
CONTENTS
WITH CDS
REGISTER
CONTENTS
WITHOUT
CDS
AVAILABLE SAMPLE
RATE
1
Colour
Pixel-by-Pixel
Yes
4MSPS
The 3 input channels
are sampled in
MCLK max
= 24MHz
SetReg1:
03(hex)
SetReg1:
01(hex)
x 3 chans
parallel. The signal is
then gain and offset
adjusted before being
multiplexed into a
single data stream
and converted by the
ADC, giving an output
data rate of 12MSPS
max.
MCLK:
VSMP
ratio is 6:1
2
3
Monochrome/
Colour
Line-by-Line
Yes
Yes
4MSPS
As mode 1 except:
Only one input
channel at a time
is continuously
sampled.
MCLK max
= 24MHz
SetReg1:
07(hex)
SetReg1:
05(hex)
x 1 chan
MCLK:
VSMP
ratio is 6:1
Fast
Monochrome/
Colour
8MSPS
Identical to mode 2
MCLK max
= 24MHz
Identical to
mode 2 plus
SetReg3:
bits 5:4 must
be set to
Identical to
mode 2
x 1 chan
MCLK:
VSMP
ratio is 3:1
Line-by-Line
0(hex)
4
5
Maximum
speed
Monochrome/
Colour
No
12MSPS
x 1 chan
Identical to mode 2
Identical to mode 1
MCLK max
= 24MHz
CDS not
possible
SetReg1:
45(hex)
MCLK:
VSMP
ratio is 2:1
Line-by-Line
Slow Colour
Pixel-by-Pixel
Yes
3MSPS
MCLK max
= 24MHz
Identical to
mode 1
Identical to
mode 1
x 3 chans
MCLK:
VSMP
ratio is
2n:1, n ≥ 4
6
Slow
Monochrome/
Colour
Yes
3MSPS
Identical to mode 2
MCLK max
= 24MHz
Identical to
mode 2
Identical to
mode 2
x 1 chan
MCLK:
VSMP
Line-by-Line
ratio is
2n:1, n ≥ 4
Table 5 WM8195 Operating Modes
Notes:
1.
2.
In Monochrome mode, Setup Register 3 bits 7:6 determine which input is to be sampled.
For Colour Line-by-Line, set control bit LINEBYLINE. For input selection, refer to Table 4, Colour Selection
Description in Line-by-Line Mode.
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WM8195
OPERATING MODE TIMING DIAGRAMS
The following diagrams show 14-bit parallel format output and MCLK, VSMP and input video
requirements for operation of the most commonly used modes as shown in Table 5. The diagrams
are identical for both CDS and non-CDS operation. Outputs from RINP, GINP and BINP are shown
as R, G and B respectively. X denotes invalid data.
16.5 MCLK PERIODS
MCLK
VSMP
INPUT VIDEO
R
B
G
R
B
R
B
G
R
B
R
B
G
R
B
R
B
G
R
B
R
B
G
R
B
OP[13:0] (DEL = 00)
OP[13:0] (DEL = 01)
G
G
G
G
G
G
R
B
R
B
G
R
B
R
B
G
R
B
R
B
G
R
B
R
B
G
R
B
R
B
OP[13:0] (DEL = 10)
OP[13:0] (DEL = 11)
G
G
G
G
G
Figure 21 Mode 1 Operation
Figure 22 Mode 2 Operation
Figure 23 Mode 3 Operation
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Figure 24 Mode 4 Operation
16.5 MCLK PERIODS
MCLK
VSMP
INPUT VIDEO
X
B
G
R
R
X
B
G
G
R
X
B
B
G
R
X
X
B
G
R
R
X
B
G
G
R
X
B
B
G
R
X
X
B
G
R
R
X
B
G
G
R
X
B
B
G
R
X
X
B
G
R
R
X
B
G
G
R
X
B
OP[13:0] (DEL = 00)
OP[13:0] (DEL = 01)
OP[13:0] (DEL = 10)
OP[13:0] (DEL = 11)
Figure 25 Mode 5 Operation (MCLK:VSMP Ratio = 8:1)
Figure 26 Mode 6 Operation (MCLK:VSMP Ratio = 8:1)
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WM8195
DEVICE CONFIGURATION
REGISTER MAP
The following table describes the location of each control bit used to determine the operation of the
WM8195. The register map is programmed by writing the required codes to the appropriate
addresses via the serial or parallel interface.
ADDRESS
<a5:a0>
000001
000010
000011
000100
000101
000110
000111
001000
001001
001010
001011
001100
100000
100001
DESCRIPTION
DEF
(hex)
03
RW
BIT
b7
b6
b5
b4
PGAFS[0]
0
b3
b2
b1
b0
Setup Reg 1
Setup Reg 2
Setup Reg 3
Software Reset
Auto-cycle Reset
Setup Reg 4
Revision Number
Setup Reg 5
Setup Reg 6
Reserved
RW
RW
RW
W
MODE4
DEL[0]
PGAFS[1]
RLCDACRNG
CDSREF [1]
SELPD
MONO
INVOP
RLCV[2]
CDS
EN
20
DEL[1]
VRLCEXT
RLCV[3]
MUXOP[1]
RLCV[1]
MUXOP[0]
RLCV[0]
1F
00
CHAN[1] CHAN[0]
CDSREF [0]
00
W
00
RW
R
FM[1]
FM[0]
INTM[1]
INTM[0]
RLCINT
FME
ACYCNRLC
LINEBYLINE
41
00
RW
RW
RW
RW
RW
RW
RW
0
0
0
POSNNEG
VDEL[2]
VDEL[1]
VDEL[0]
VSMPDET
00
0
0
0
0
SELDIS[3]
SELDIS[2]
SELDIS[1]
SELDIS[0]
00
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
Reserved
00
Reserved
00
0
0
0
0
0
0
0
0
DAC Value (Red)
80
DAC[7]
DAC[7]
DAC[6]
DAC[6]
DAC[5]
DAC[5]
DAC[4]
DAC[4]
DAC[3]
DAC[3]
DAC[2]
DAC[2]
DAC[1]
DAC[1]
DAC[0]
DAC[0]
DAC Value
(Green)
80
100010
100011
101000
101001
DAC Value (Blue)
DAC Value (RGB)
PGA Gain (Red)
80
80
00
00
RW
W
DAC[7]
DAC[7]
PGA[7]
PGA[7]
DAC[6]
DAC[6]
PGA[6]
PGA[6]
DAC[5]
DAC[5]
PGA[5]
PGA[5]
DAC[4]
DAC[4]
PGA[4]
PGA[4]
DAC[3]
DAC[3]
PGA[3]
PGA[3]
DAC[2]
DAC[2]
PGA[2]
PGA[2]
DAC[1]
DAC[1]
PGA[1]
PGA[1]
DAC[0]
DAC[0]
PGA[0]
PGA[0]
RW
RW
PGA Gain
(Green)
101010
101011
PGA Gain (Blue)
PGA Gain (RGB)
00
00
RW
W
PGA[7]
PGA[7]
PGA[6]
PGA[6]
PGA[5]
PGA[5]
PGA[4]
PGA[4]
PGA[3]
PGA[3]
PGA[2]
PGA[2]
PGA[1]
PGA[1]
PGA[0]
PGA[0]
Table 6 Register Map
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REGISTER MAP DESCRIPTION
The following table describes the function of each of the control bits shown in Table 7.
REGISTER
BIT
NO
BIT
NAME(S)
DEFAULT
DESCRIPTION
Setup
0
EN
1
When SELPD = 1 this bit has no effect.
Register 1
When SELPD = 0 this bit controls the global power down:
0 = complete power down, 1 = fully active.
1
CDS
1
Select correlated double sampling mode: 0 = single ended mode,
1 = CDS mode.
2
3
MONO
SELPD
0
0
Mono/colour select: 0 = colour, 1 = monochrome operation.
Selective power down: 0 = no individual control,
1 = individual blocks can be disabled (controlled by SELDIS[3:0]).
5:4
PGAFS[1:0]
00
Offsets PGA output to optimise the ADC range for different polarity sensor
output signals. Zero differential PGA input signal gives:
00 = Zero output
(use for bipolar video)
01 = Zero output
10 = Full-scale positive output
(use for negative going video)
11 = Full-scale negative output
(use for positive going video)
6
MODE4
0
Required when operating in MODE4: 0 = other modes, 1 = MODE4.
Determines the output data format.
Setup
1:0
MUXOP[1:0]
00
Register 2
00 = 14-bit parallel
10 = 7-bit multiplexed mode (7+7 bits)
01 = 8-bit multiplexed (8+6 bits)
11 = 4-bit multiplexed mode (4+4+4+2 bits)
2
INVOP
0
Digitally inverts the polarity of output data.
0 = negative going video gives negative going output,
1 = negative going video gives positive going output data.
3
5
VRLCEXT
0
1
When set powers down the RLCDAC, changing its output to Hi-Z, allowing
VRLC/VBIAS to be externally driven.
RLCDACRNG
Sets the output range of the RLCDAC.
0 = RLCDAC ranges from 0 to AVDD (approximately),
1 = RLCDAC ranges from 0 to VRT (approximately).
7:6
DEL[1:0]
00
Sets the output latency in ADC clock periods.
1 ADC clock period = 2 MCLK periods except in Mode 3 where 1 ADC clock
period = 3 MCLK periods.
00 = Minimum latency
01 = Delay by one ADC clock
period
10 = Delay by two ADC clock periods
11 = Delay by three ADC clock periods
Setup
Register 3
3:0
5:4
RLCV[3:0]
1111
01
Controls RLCDAC driving VRLC/VBIAS pin to define single ended signal
reference voltage or Reset Level Clamp voltage. See Electrical Characteristics
section for ranges.
CDSREF[1:0]
CDS mode reset timing adjust.
00 = Advance 1 MCLK period
01 = Normal
10 = Retard 1 MCLK period
11 = Retard 2 MCLK periods
7:6
CHAN[1:0]
00
Monochrome mode channel select.
00 = Red channel select
01 = Green channel select
10 = Blue channel select
11 = Reserved
Software
Reset
Any write to Software Reset causes all cells to be reset. It is recommended
that a software reset be performed after a power-up before any other register
writes.
Auto-cycle
Reset
Any write to Auto-cycle Reset causes the auto-cycle counter to reset
to RINP. This function is only required when LINEBYLINE = 1.
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WM8195
REGISTER
BIT
NO
BIT
NAME(S)
DEFAULT
DESCRIPTION
Setup
Register 4
0
LINEBYLINE
0
Selects line by line operation 0 = normal operation,
1 = line by line operation.
When line by line operation is selected MONO is forced to 1 and CHAN[1:0] to
00 internally, ensuring that the correct internal timing signals are produced.
Green and Blue PGAs are also disabled to save power.
1
ACYCNRLC
0
When LINEBYLINE = 0 this bit has no effect.
When LINEBYLINE = 1 this bit determines the function of the RLC/ACYC input
pin and the input multiplexer and offset/gain register controls.
0 = RLC/ACYC pin enabled for Reset Level Clamp. Internal selection of input
and gain/offset multiplexers,
1 = Auto-cycling enabled by pulsing the RLC/ACYC input pin.
See Table 4, Colour Selection Description in Line-by-Line Mode for colour
selection mode details.
When auto-cycling is enabled, the RLC/ACYC pin cannot be used for reset
level clamping. The RLCINT bit may be used instead.
2
FME
0
When LINEBYLINE = 0 this bit has no effect.
When LINEBYLINE = 1 this bit controls the input force mux mode:
0 = No force mux, 1 = Force mux mode. Forces the input mux to be selected
by FM[1:0] separately from gain and offset multiplexers.
See Table 4 for details.
3
RLCINT
0
When LINEBYLINE = 1 and ACYCNRLC = 1 this bit is used to determine
whether Reset Level Clamping is used.
0 = RLC disabled, 1 = RLC enabled.
5:4
INTM[1:0]
00
Colour selection bits used in internal modes.
00 = Red, 01 = Green, 10 = Blue and 11 = Reserved.
See Table 4 for details.
7:6
0
FM[1:0]
00
0
Colour selection bits used in input force mux modes.
00 = RINP, 01 = GINP, 10 = BINP and 11 = Reserved.
See Table 4 for details.
Setup
Register 5
VSMPDET
0 = Normal operation, signal on VSMP input pin is applied directly to Timing
Control block.
1 = Programmable VSMP detect circuit is enabled. An internal synchronisation
pulse is generated from signal applied to VSMP input pin and is applied to
Timing Control block.
3:1
4
VDEL[2:0]
000
When VSMPDET = 0 these bits have no effect.
When VSMPDET = 1 these bits set a programmable delay from the detected
edge of the signal applied to the VSMP pin. The internally generated pulse is
delayed by VDEL MCLK periods from the detected edge.
See Figure 19, Internal VSMP Pulses Generated for details.
POSNNEG
0
When VSMPDET = 0 this bit has no effect.
When VSMPDET = 1 this bit controls whether positive or negative edges
are detected:
0 = Negative edge on VSMP pin is detected and used to generate internal
timing pulse.
1 = Positive edge on VSMP pin is detected and used to generate internal
timing pulse.
See Figure 19 for further details.
Setup
Register 6
3:0
SELDIS[3:0]
0000
Selective power disable register - activated when SELPD = 1.
Each bit disables respective cell when 1, enabled when 0.
SELDIS[0] = Red CDS, PGA
SELDIS[1] = Green CDS, PGA
SELDIS[2] = Blue CDS, PGA
SELDIS[3] = ADC
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WM8195
Production Data
REGISTER
BIT
NO
BIT
NAME(S)
DEFAULT
DESCRIPTION
Offset DAC
(Red)
7:0
DAC[7:0]
0
Red channel offset DAC value.
Offset DAC
(Green)
7:0
7:0
7:0
DAC[7:0]
DAC[7:0]
DAC[7:0]
0
0
0
Green channel offset DAC value
Blue channel offset DAC value
Offset DAC
(Blue)
Offset DAC
(RGB)
A write to this register location causes the red, green and blue offset DAC
registers to be overwritten by the new value
PGA gain
(Red)
7:0
7:0
7:0
7:0
PGA[7:0]
PGA[7:0]
PGA[7:0]
PGA[7:0]
0
0
0
0
Determines the gain of the red channel PGA according to the equation:
Red channel PGA gain = 208/(283-PGA[7:0])
PGA gain
(Green)
Determines the gain of the green channel PGA according to the equation:
Green channel PGA gain = 208/(283-PGA[7:0])
PGA gain
(Blue)
Determines the gain of the blue channel PGA according to the equation:
Blue channel PGA gain = 208/(283-PGA[7:0])
PGA gain
(RGB)
A write to this register location causes the red, green and blue PGA gain
registers to be overwritten by the new value
Table 7 Register Control Bits
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WM8195
RECOMMENDED EXTERNAL COMPONENTS
DVDD1
DVDD2, 3
10
24
35
18
25
30
36
40
DVDD1
DVDD2
DVDD3
DGND1
DGND2
DGND3
DGND4
DGND5
C1
C2
C3
3
5
DGND
AGND1
AGND2
AGND3
AGND4
AGND5
AGND6
AVDD
43
44
AVDD1
AVDD2
7
C4
9
45
46
AGND
8
6
4
RINP
GINP
BINP
AGND
Video
Inputs
48
1
VRT
VRX
VRB
C5
C6
2
47
VRLC/VBIAS
C10
C7
C8
C9
WM8195
AGND
AGND
17
15
39
38
37
34
33
32
31
29
28
27
26
23
22
21
MCLK
VSMP
OP[13]/SDO
OP[12]
OP[11]
OP[10]
OP[9]
Timing
Signals
12
14
13
16
42
SEN/STB
SCK/RNW
SDI/DNA
RLC/ACYC
NRESET
DVDD1
DVDD2, 3 AVDD1, 2
OP[8]
C11
+
C12
C13
+
Interface
Controls
Output
Data
Bus
+
OP[7]
OP[6]
OP[5]
11
OEB
OP[4]
AGND
OP[3]
OP[2]
OP[1]
OP[0]
NOTES: 1. C1-10 should be fitted as close to WM8195 as possible.
2. AGND1-6 and DGND1-5 should be connected as close to WM8195 as possible.
3. DVDD1-3 should be connected as close to WM8195 as possible.
Figure 27 External Components Diagram
COMPONENT
REFERENCE
SUGGESTED
VALUE
DESCRIPTION
C1
C2
100nF
100nF
100nF
100nF
10nF
1µF
De-coupling for DVDD1.
De-coupling for DVDD2.
De-coupling for DVDD3.
C3
C4
De-coupling for AVDD1 and AVDD2.
High frequency de-coupling between VRT and VRB.
C5
C6
Low frequency de-coupling between VRT and VRB (non-polarised).
De-coupling for VRB.
C7
100nF
100nF
100nF
100nF
1µF
C8
De-coupling for VRX.
C9
De-coupling for VRT.
C10
C11
C12
C13
De-coupling for VRLC.
Reservoir capacitor for DVDD1.
Reservoir capacitor for DVDD2 and DVDD3.
Reservoir capacitor for AVDD1 and AVDD2.
1µF
1µF
Table 8 External Components Descriptions
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WM8195
Production Data
PACKAGE DIMENSIONS
FT: 48 PIN TQFP (7 x 7 x 1.0 mm)
DM004.C
b
e
36
25
37
24
E1
E
48
13
1
12
Θ
D1
D
c
L
A1
A
A2
-C-
SEATING PLANE
ccc C
Dimensions
(mm)
Symbols
MIN
-----
0.05
0.95
0.17
0.09
NOM
-----
-----
1.00
0.22
-----
MAX
1.20
0.15
1.05
0.27
0.20
A
A1
A2
b
c
D
D1
E
E1
e
L
Θ
9.00 BSC
7.00 BSC
9.00 BSC
7.00 BSC
0.50 BSC
0.60
0.45
0o
0.75
7o
3.5o
Tolerances of Form and Position
0.08
ccc
REF:
JEDEC.95, MS-026
NOTES:
A. ALL LINEAR DIMENSIONS ARE IN MILLIMETERS.
B. THIS DRAWING IS SUBJECT TO CHANGE WITHOUT NOTICE.
C. BODY DIMENSIONS DO NOT INCLUDE MOLD FLASH OR PROTRUSION, NOT TO EXCEED 0.25MM.
D. MEETS JEDEC.95 MS-026, VARIATION = ABC. REFER TO THIS SPECIFICATION FOR FURTHER DETAILS.
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WM8195
IMPORTANT NOTICE
Wolfson Microelectronics plc (WM) reserve the right to make changes to their products or to discontinue any product or
service without notice, and advise customers to obtain the latest version of relevant information to verify, before placing
orders, that information being relied on is current. All products are sold subject to the WM terms and conditions of sale
supplied at the time of order acknowledgement, including those pertaining to warranty, patent infringement, and limitation
of liability.
WM warrants performance of its products to the specifications applicable at the time of sale in accordance with WM’s
standard warranty. Testing and other quality control techniques are utilised to the extent WM deems necessary to support
this warranty. Specific testing of all parameters of each device is not necessarily performed, except those mandated by
government requirements.
In order to minimise risks associated with customer applications, adequate design and operating safeguards must be used
by the customer to minimise inherent or procedural hazards. Wolfson products are not authorised for use as critical
components in life support devices or systems without the express written approval of an officer of the company. Life
support devices or systems are devices or systems that are intended for surgical implant into the body, or support or
sustain life, and whose failure to perform when properly used in accordance with instructions for use provided, can be
reasonably expected to result in a significant injury to the user. A critical component is any component of a life support
device or system whose failure to perform can be reasonably expected to cause the failure of the life support device or
system, or to affect its safety or effectiveness.
WM assumes no liability for applications assistance or customer product design. WM does not warrant or represent that
any license, either express or implied, is granted under any patent right, copyright, mask work right, or other intellectual
property right of WM covering or relating to any combination, machine, or process in which such products or services might
be or are used. WM’s publication of information regarding any third party’s products or services does not constitute WM’s
approval, license, warranty or endorsement thereof.
Reproduction of information from the WM web site or datasheets is permissible only if reproduction is without alteration and
is accompanied by all associated warranties, conditions, limitations and notices. Representation or reproduction of this
information with alteration voids all warranties provided for an associated WM product or service, is an unfair and deceptive
business practice, and WM is not responsible nor liable for any such use.
Resale of WM’s products or services with statements different from or beyond the parameters stated by WM for that
product or service voids all express and any implied warranties for the associated WM product or service, is an unfair and
deceptive business practice, and WM is not responsible nor liable for any such use.
ADDRESS:
Wolfson Microelectronics plc
Westfield House
26 Westfield Road
Edinburgh
EH11 2QB
United Kingdom
Tel :: +44 (0)131 272 7000
Fax :: +44 (0)131 272 7001
Email :: sales@wolfsonmicro.com
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