a
CCD Signal Processors with
Integrated Timing Driver
AD9848/AD9849
FEATURES
AD9848: 10-Bit, 20 MHz Version
AD9849: 12-Bit, 30 MHz Version
Correlated Double Sampler (CDS)
–2 dB to +10 dB Pixel Gain Amplifier ( PxGA®)
2 dB to 36 dB 10-Bit Variable Gain Amplifier (VGA)
10-Bit 20 MHz A/D Converter (AD9848)
12-Bit 30 MHz A/D Converter (AD9849)
Black Level Clamp with Variable Level Control
Complete On-Chip Timing Driver
Precision Timing™ Core with 1 ns Resolution @ 20 MSPS
On-Chip 3 V Horizontal and RG Drivers (AD9848)
On-Chip 5 V Horizontal and RG Drivers (AD9849)
48-Lead LQFP Package
APPLICATIONS
Digital Still Cameras
PRODUCT DESCRIPTION
The AD9848 and AD9849 are highly integrated CCD signal processors for digital still camera applications. Both include a complete
analog front end with A/D conversion, combined with a programmable timing driver. The Precision Timing core allows adjustment
of high speed clocks with approximately 1 ns resolution.
The AD9848 is specified at pixel rates of 20 MHz, and the
AD9849 is specified at 30 MHz. The analog front end includes
black level clamping, CDS, PxGA, VGA, and a 10- or 12-bit A/D
converter. The timing driver provides the high-speed CCD clock
drivers for RG and H1-H4. Operation is programmed using a
3-wire serial interface.
Packaged in a space-saving 48-lead LQFP, the AD9848 and
AD9849 are specified over an operating temperature range of
–20°C to +85°C.
FUNCTIONAL BLOCK DIAGRAM
VRT
4ⴞ6dB
2dB TO 36dB
VRB
VREF
10 OR 12
CDS
CCDIN
DOUT
ADC
VGA
PxGA
CLAMP
CLAMP
INTERNAL
CLOCKS
CLPOB
CLPDM
RG
H1–H4
4
HORIZONTAL
DRIVERS
PRECISION
TIMINGTM
CORE
AD9848/AD9849
SYNC
GENERATOR
HD
VD
PBLK
CLI
INTERNAL
REGISTERS
SL
SCK
SDATA
PxGA is a registered trademark and Precision Timing is a trademark of Analog Devices, Inc.
REV. 0
Information furnished by Analog Devices is believed to be accurate and
reliable. However, no responsibility is assumed by Analog Devices for its
use, nor for any infringements of patents or other rights of third parties that
may result from its use. No license is granted by implication or otherwise
under any patent or patent rights of Analog Devices.
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: 781/329-4700
www.analog.com
Fax: 781/326-8703
© Analog Devices, Inc., 2001
AD9848/AD9849 –TARGET SPECIFICATIONS
GENERAL SPECIFICATIONS
Parameter
Min
TEMPERATURE RANGE
Operating
Storage
–20
–65
MAXIMUM CLOCK RATE
AD9848
AD9849
20
30
POWER SUPPLY VOLTAGE, AD9848
Analog (AVDD1, 2, 3)
Digital1 (DVDD1) H1–H4
Digital2 (DVDD2) RG
Digital3 (DVDD3) D0–D11
Digital4 (DVDD4) All Other Digital
Typ
Max
Unit
+85
+150
°C
°C
MHz
MHz
3.6
3.6
3.6
V
V
V
V
V
3.6
5.5
5.5
3.0
3.0
V
V
V
V
V
POWER DISSIPATION, AD9848
20 MHz, DVDD1, 2 = 3 V, 100 pF H Loading
Total Shutdown Mode
220
1
mW
mW
POWER DISSIPATION, AD9849
30 MHz, DVDD1, 2 = 5 V, 100 pF H Loading
Total Shutdown Mode
450
1
mW
mW
POWER SUPPLY VOLTAGE, AD9849
Analog (AVDD1, 2, 3)
Digital1 (DVDD1) H1–H4
Digital2 (DVDD2) RG
Digital3 (DVDD3) D0–D11
Digital4 (DVDD4) All Other Digital
2.7
2.7
2.7
3.0
3.0
2.7
3.0
3.0
Specifications subject to change without notice.
–2–
REV. 0
AD9848/AD9849
DIGITAL SPECIFICATIONS
(TMIN to TMAX, AVDD1 = DVDD3, DVDD4 = 2.7 V, DVDD1, DVDD2 = 2.7 V [AD9848], DVDD1,
DVDD2 = 5.25 V [AD9849], CL = 20 pF, unless otherwise noted.)
Parameter
Symbol
Min
LOGIC INPUTS
High Level Input Voltage
Low Level Input Voltage
High Level Input Current
Low Level Input Current
Input Capacitance
VIH
VIL
IIH
IIL
CIN
2.1
LOGIC OUTPUTS
High Level Output Voltage, IOH = 2 mA
Low Level Output Voltage, IOL = 2 mA
VOH
VOL
2.2
CLI INPUT
High Level Input Voltage
(AVDD1, 2 +0.5 V)
Low Level Input Voltage
VIH–CLI
VIL–CLI
1.85
RG AND H-DRIVER OUTPUTS, AD9848
High Level Output Voltage
(DVDD1, 2 –0.5 V)
Low Level Output Voltage
Maximum Output Current (Programmable)
Maximum Load Capacitance
VOH
VOL
2.2
RG AND H-DRIVER OUTPUTS, AD9849
High Level Output Voltage
(DVDD1, 2 –0.5 V)
Low Level Output Voltage
Maximum Output Current (Programmable)
Maximum Load Capacitance
VOH
VOL
Max
0.6
10
10
10
0.85
V
V
4.75
0.5
–3–
V
V
µA
µA
pF
V
V
24
100
24
100
Unit
0.5
0.5
Specifications subject to change without notice.
REV. 0
Typ
V
V
mA
pF
V
V
mA
pF
AD9848/AD9849
AD9848–ANALOG SPECIFICATIONS (T
Parameter
Min
CDS
Gain
Allowable CCD Reset Transient1
Max Input Range Before Saturation1
Max CCD Black Pixel Amplitude1
PIXEL GAIN AMPLIFIER (PxGA)
Max Input Range
Max Output Range
Gain Control Resolution
Gain Monotonicity
Gain Range
Min Gain (32)
Med Gain (0)
Max Gain (31)
VARIABLE GAIN AMPLIFIER (VGA)
Max Input Range
Max Output Range
Gain Control Resolution
Gain Monotonicity
Gain Range
Low Gain (91)
Max Gain (1023)
to TMAX, AVDD = DVDD = 3.0 V, fCLI = 20 MHz, unless otherwise noted.)
Typ
Max
0
500
Unit
dB
mV
V p-p
mV
1.0
150
1.0
1.6
Notes
See Input Waveform in Note 1
V p-p
V p-p
Steps
64
Guaranteed
–2
4
10
dB
dB
dB
1.6
2.0
Medium Gain (4 dB) Is Default Setting
V p-p
V p-p
Steps
1024
Guaranteed
BLACK LEVEL CLAMP
Clamp Level Resolution
Clamp Level
Min Clamp Level (0)
Max Clamp Level (255)
A/D CONVERTER
Resolution
Differential Nonlinearity (DNL)
No Missing Codes
Full-Scale Input Voltage
MIN
2
36
dB
dB
256
Steps
0
63.75
LSB
LSB
Measured at ADC Output
10
VOLTAGE REFERENCE
Reference Top Voltage (VRT)
Reference Bottom Voltage (VRB)
± 0.4
± 1.0
Guaranteed
2.0
2.0
1.0
V
V
V
SYSTEM PERFORMANCE
VGA Gain Accuracy
Low Gain (91)
5
Max Gain (1023)
38
Peak Nonlinearity, 500 mV Input Signal
Total Output Noise
Power Supply Rejection (PSR)
Bits
LSB
Specifications Include Entire Signal Chain
Gain Includes 4 dB Default PxGA Gain
6
39.5
0.2
0.2
40
7
41
dB
dB
%
12 dB Gain Applied
LSB rms AC Grounded Input, 6 dB Gain Applied
dB
Measured with Step Change on Supply
NOTES
1
Input signal characteristics defined as follows:
500mV TYP
RESET
TRANSIENT
150mV MAX
OPTICAL
BLACK PIXEL
1V MAX
INPUT
SIGNAL RANGE
Specifications subject to change without notice.
–4–
REV. 0
AD9848/AD9849
AD9849–ANALOG SPECIFICATIONS (T
Parameter
Min
CDS
Gain
Allowable CCD Reset Transient1
Max Input Range Before Saturation1
Max CCD Black Pixel Amplitude1
PIXEL GAIN AMPLIFIER (PxGA)
Max Input Range
Max Output Range
Gain Control Resolution
Gain Monotonicity
Gain Range
Min Gain (32)
Med Gain (0)
Max Gain (31)
VARIABLE GAIN AMPLIFIER (VGA)
Max Input Range
Max Output Range
Gain Control Resolution
Gain Monotonicity
Gain Range
Low Gain (91)
Max Gain (1023)
to TMAX, AVDD = DVDD = 3.0 V, fCLI = 30 MHz, unless otherwise noted.)
Typ
Max
0
500
150
1.0
1.6
–2
4
10
dB
dB
dB
1.6
2.0
1024
Guaranteed
Medium Gain (4 dB) Is Default Setting
2
36
dB
dB
256
Steps
0
255
LSB
LSB
Measured at ADC Output
12
Low Gain (91)
5
Max Gain (1023)
38
Peak Nonlinearity, 500 mV Input Signal
Total Output Noise
Power Supply Rejection (PSR)
± 0.5
± 1.0
Guaranteed
2.0
2.0
1.0
Bits
LSB
V
V
V
Specifications Include Entire Signal Chain
Gain Includes 4 dB Default PxGA Gain
6
39.5
0.2
0.6
40
7
41
NOTES
1
Input signal characteristics defined as follows:
1V MAX
INPUT
SIGNAL RANGE
Specifications subject to change without notice.
REV. 0
See Input Waveform in Note 1
V p-p
V p-p
Steps
SYSTEM PERFORMANCE
Gain Accuracy
150mV MAX
OPTICAL
BLACK PIXEL
Notes
V p-p
V p-p
Steps
64
Guaranteed
VOLTAGE REFERENCE
Reference Top Voltage (VRT)
Reference Bottom Voltage (VRB)
500mV TYP
RESET
TRANSIENT
Unit
dB
mV
V p-p
mV
1.0
BLACK LEVEL CLAMP
Clamp Level Resolution
Clamp Level
Min Clamp Level (0)
Max Clamp Level (255)
A/D CONVERTER
Resolution
Differential Nonlinearity (DNL)
No Missing Codes
Full-Scale Input Voltage
MIN
–5–
dB
dB
%
12 dB Gain Applied
LSB rms AC Grounded Input, 6 dB Gain Applied
dB
Measured with Step Change on Supply
AD9848/AD9849
TIMING SPECIFICATIONS
(CL = 20 pF, fCLI = 20 MHz [AD9848] or 30 MHz [AD9849], Serial Timing in Figure 3, unless
otherwise noted.)
Parameter
Symbol
Min
MASTER CLOCK (CLI), AD9848
CLI Clock Period
CLI High/Low Pulsewidth
Delay From CLI to Internal Pixel Period Position
tCLI
tADC
tCLIDLY
50
25
MASTER CLOCK (CLI), AD9849
CLI Clock Period
CLI High/Low Pulsewidth
tCONV
tADC
33.33
16.67
EXTERNAL MODE CLAMPING
CLPDM Pulsewidth
CLPOB Pulsewidth1
tCDM
tCOB
4
2
SAMPLE CLOCKS
SHP Rising Edge to SHD Rising Edge (AD9848)
SHP Rising Edge to SHD Rising Edge (AD9849)
tS1
tS1
20
13
DATA OUTPUTS
Output Delay from Programmed Edge
Pipeline Delay
SERIAL INTERFACE
Maximum SCK Frequency
SL to SCK Setup Time
SCK to SL Hold Time
SDATA Valid to SCK Rising Edge Setup
SCK Falling Edge to SDATA Valid Hold
SCK Falling Edge to SDATA Valid Read
Typ
Max
6
tOD
ns
ns
ns
ns
ns
10
20
Pixels
Pixels
ns
ns
6
9
10
10
10
10
10
10
fSCLK
tLS
tLH
tDS
tDH
tDV
Unit
ns
Cycles
MHz
ns
ns
ns
ns
ns
NOTES
1
Maximum CLPOB pulsewidth is for functional operation only. Wider typical pulses are recommended to achieve low noise clamp reference.
Specifications subject to change without notice.
–6–
REV. 0
AD9848/AD9849
ABSOLUTE MAXIMUM RATINGS
Parameter
AVDD1, 2, 3
DVDD1, DVDD2 (AD9848)
DVDD1, DVDD2 (AD9849)
DVDD3, 4
Digital Outputs
CLPOB, CLPDM, BLK
CLI
SCK, SL, SDATA
VRT, VRB
BYP1 – 3, CCDIN
Junction Temperature
Lead Temperature (10 sec)
With
Respect
To
Min
Max
Unit
AVSS
DVSS
DVSS
DVSS
DVSS3
DVSS4
AVSS
DVSS4
AVSS
AVSS
–0.3
–0.3
–0.3
–0.3
–0.3
–0.3
–0.3
–0.3
–0.3
–0.3
+3.9
+3.9
+5.5
+3.9
DVDD3 + 0.3
DVDD4 + 0.3
AVDD + 0.3
DVDD4 + 0.3
AVDD + 0.3
AVDD + 0.3
150
300
V
V
V
V
V
V
V
V
V
V
°C
°C
THERMAL CHARACTERISTICS
Thermal Resistance
48-Lead LQFP Package
JA = 92°C
ORDERING GUIDE
Model
Temperature
Range
Package
Description
Package
Option
AD9848KST
AD9849KST
–20°C to +85°C
–20°C to +85°C
Thin Plastic Quad Flatpack (LQFP)
Thin Plastic Quad Flatpack (LQFP)
ST-48
ST-48
CAUTION
ESD (electrostatic discharge) sensitive device. Electrostatic charges as high as 4000 V readily
accumulate on the human body and test equipment and can discharge without detection. Although
the AD9848/AD9849 features proprietary ESD protection circuitry, permanent damage may occur
on devices subjected to high-energy electrostatic discharges. Therefore, proper ESD precautions
are recommended to avoid performance degradation or loss of functionality.
REV. 0
–7–
WARNING!
ESD SENSITIVE DEVICE
AD9848/AD9849
36
SL
D2 1
35
REFT
D3 2
D2 3
D3 4
34
REFB
33
CMLEVEL
D4 5
DVSS3 6
32
AVSS3
31
AVDD3
BYP3
29 CCDIN
D6 9
28
SDI
SCK
CLPOB
CLPDM
HBLK
PBLK
VD
HD
32
AVSS3
31
AVDD3
AD9849
TOP VIEW
(Not to Scale)
30
BYP3
29 CCDIN
BYP2
BYP1
26 AVDD2
D8 9
D9 10
28
27
27
D10 11
26
BYP1
AVDD2
25
AVSS2
(MSB) D11 12
25
AVSS2
BYP2
AVDD1
CLI
AVSS1
DVDD2
RG
DVSS2
H1
H4
13 14 15 16 17 18 19 20 21 22 23 24
AVDD1
CLI
AVSS1
DVDD2
RG
DVSS2
H4
H3
DVDD1
DVSS1
H2
DVSS4
CMLEVEL
D6 5
DVSS3 6
13 14 15 16 17 18 19 20 21 22 23 24
H1
NC = NO CONNECT
REFB
33
H3
D8 11
(MSB) D9 12
34
DVDD3 7
D7 8
30
D7 10
REFT
D4 3
D5 4
DVDD1
TOP VIEW
(Not to Scale)
DVDD3 7
D5 8
SL
35
DVSS1
AD9848
36
PIN 1
IDENTIFIER
H2
PIN 1
IDENTIFIER
DVDD4
48 47 46 45 44 43 42 41 40 39 38 37
48 47 46 45 44 43 42 41 40 39 38 37
(LSB) D0 1
D1 2
D0 (LSB)
D1
SDI
SCK
CLPOB
CLPDM
HBLK
PBLK
VD
HD
DVSS4
DVDD4
NC
NC
PIN CONFIGURATION
PIN FUNCTION DESCRIPTIONS
Pin
Mnemonic
Type
Description
1–5
1–5
6
7
8–12
8–12
13, 14
15
16
17, 18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47, 48
47, 48
D0–D4
D2–D6
DVSS3
DVDD3
D5–D9
D7–D11
H1, H2
DVSS1
DVDD1
H3, H4
DVSS2
RG
DVDD2
AVSS1
CLI
AVDD1
AVSS2
AVDD2
BYP1
BYP2
CCDIN
BYP3
AVDD3
AVSS3
CMLEVEL
REFB
REFT
SL
SDI
SCK
CLPOB
CLPDM
HBLK
PBLK
VD
HD
DVSS4
DVDD4
NC
D0, D1
DO
DO
P
P
DO
DO
DO
P
P
DO
P
DO
P
P
DI
P
P
P
AO
AO
AI
AO
P
P
AO
AO
AO
DI
DI
DI
DI
DI
DI
DI
DI
DI
P
P
NC
DO
Data Outputs AD9848 Only
Data Outputs AD9849 Only
Digital Ground 3 – Data Outputs
Digital Supply 3 – Data Outputs
Data Outputs (D9 is MSB) AD9848 Only
Data Outputs (D9 is MSB) AD9849 Only
Horizontal Clocks (to CCD)
Digital Ground 1 – H Drivers
Digital Supply 1 – H Drivers
Horizontal Clocks (to CCD)
Digital Ground 1 – H Drivers
Reset Gate Clock (to CCD)
Digital Supply 2 – RG Driver
Analog Ground 1
Master Clock Input
Analog Supply 1
Analog Ground 2
Analog Supply 2
Bypass Pin (0.1 µF to AVSS)
Bypass Pin (0.1 µF to AVSS)
Analog Input for CCD Signal
Bypass Pin (0.1 µF to AVSS)
Analog Supply 3
Analog Ground 3
Internal Bias Level Decoupling (0.1 µF to AVSS)
Reference Bottom Decoupling (1.0 µF to AVSS)
Reference Top Decoupling (1.0 µF to AVSS)
3-Wire Serial Load (from µP)
3-Wire Serial Data Input (from µP)
3-Wire Serial Clock (from µP)
Optical Black Clamp Pulse
Dummy Black Clamp Pulse
HCLK Blanking Pulse
Preblanking Pulse
Vertical Sync Pulse
Horizontal Sync Pulse
Digital Ground 4 – VD, HD, CLPOB, CLPDM, HBLK, PBLK, SCK, SL, SDATA
Digital Supply 4 – VD, HD, CLPOB, CLPDM, HBLK, PBLK, CK, SL, SDATA
Internally Not Connected AD9848 Only
Data Output (D0 is LSB) AD9849 Only
NOTE
Type: AI = Analog Input, AO = Analog Output, DI = Digital Input, DO = Digital Output, P = Power
–8–
REV. 0
AD9848/AD9849
EQUIVALENT INPUT/OUTPUT CIRCUITS
DVDD4
AVDD2
330⍀
R
DVSS4
AVSS2
AVSS2
Circuit 1. CCDIN (Pin 29)
Circuit 4. Digital Inputs (Pins 36–44)
DVDD1
DATA
AVDD1
330⍀
25k⍀
ENABLE
CLI
OUTPUT
1.4V
AVSS1
DVSS1
Circuit 5. H1–H4 and RG (Pins 13, 14, 17, 18, 20)
Circuit 2. CLI (Pin 23)
DVDD4
DVDD3
DATA
THREESTATE
DOUT
DVSS4
DVSS3
Circuit 3. Data Outputs D0–D11 (Pins 1–5, 8–12, 47–48)
REV. 0
–9–
AD9848/AD9849—Typical Linearity and Noise Performance Characteristics
0.50
0.5
0.25
0.25
0
0
–0.25
–0.25
–0.5
–0.50
0
200
400
600
800
0
1000
500
1000
1500
2000
2500
3000
3500
4000
TPC 3. AD9849 Typical DNL
TPC 1. AD9848 Typical DNL
15
4
OUTPUT NOISE – LSB
OUTPUT NOISE – LSB
3
2
10
5
1
0
0
0
200
400
600
VGA GAIN CODE – LSB
800
0
1000
TPC 2. AD9848 Output Noise vs. VGA Gain Setting
200
400
600
VGA GAIN CODE – LSB
800
1000
TPC 4. AD9849 Output Noise vs. VGA Gain Setting
–10–
REV. 0
AD9848/AD9849
SYSTEM OVERVIEW
V-DRIVER
V1–V4, VSG1–VSG8, SUBCK
V-DRIVER
V1–V4, VSG1–VSG8, SUBCK
H1–H4, RG
DOUT
H1–H4, RG
CLPOB
DOUT
CCD
CCD
CCDIN
AD9848/AD9849
INTEGRATED
AFE+TD
HD, VD
DIGITAL IMAGE
PROCESSING
ASIC
CCDIN
AD9848/AD9849
INTEGRATED
AFE+TD
CLPDM
PBLK
DIGITAL IMAGE
PROCESSING
ASIC
HBLK
HD, VD
CLI
CLI
SERIAL
INTERFACE
SERIAL
INTERFACE
Figure 1b. Typical Application (External Mode)
Figure 1a. Typical Application (Internal Mode)
Figure 1a and 1b show the typical system application diagrams
for the AD9848/AD9849. The CCD output is processed by the
AD9848/AD9849’s AFE circuitry, which consists of a CDS,
PxGA, VGA, black level clamp, and A/D converter. The digitized pixel information is sent to the digital image processor
chip, where all post-processing and compression occurs. To
operate the CCD, CCD timing parameters are programmed
into the AD9848/AD9849 from the image processor, through
the 3-wire serial interface. From the system master clock, CLI,
provided by the image processor, the AD9848/AD9849 generates the high speed CCD clocks and all internal AFE clocks. All
AD9848/AD9849 clocks are synchronized with VD and HD.
Figure 2 shows the horizontal and vertical counter dimensions
for the AD9848/AD9849. All internal horizontal clocking is
programmed using these dimensions, to specify line and
pixel locations.
MAXIMUM FIELD DIMENSIONS
12-BIT HORIZONTAL = 4096 PIXELS MAX
Figure 1a shows the AD9848/AD9849 used in Internal mode,
in which all the horizontal pulses (CLPOB, CLPDM, PBLK,
and HBLK) are programmed and generated internally. Figure 1b
shows the AD9848/AD9849 operating in external mode, in
which the horizontal pulses are supplied externally by the
image processor.
12-BIT VERTICAL = 4096 LINES MAX
The H-drivers for H1–H4 and RG are included in the AD9848/
AD9849, allowing these clocks to be directly connected to the
CCD. H-drive voltage of 5 V is supported in the AD9849.
REV. 0
Figure 2. Vertical and Horizontal Counters
–11–
AD9848/AD9849
SERIAL INTERFACE TIMING
SDATA
A0
A1
A2
A3
t DS
A4
A5
A6
A7
D0
D1
D2
D3
D4
D5
XX
XX
t DH
SCK
t LS
t LH
SL
SL UPDATED
VD/HD UPDATED
VD
HD
NOTES
1. SDATA BITS ARE LATCHED ON SCK RISING EDGES.
2. 14 SCK EDGES ARE NEEDED TO WRITE ADDRESS AND DATA BITS.
3. FOR 16-BIT SYSTEMS, TWO EXTRA DUMMY BITS MAY BE WRITTEN. DUMMY BITS ARE IGNORED.
4. NEW DATA IS UPDATED AT EITHER THE SL RISING EDGE, OR AT THE HD FALLING EDGE AFTER THE NEXT VD FALLING EDGE.
5. VD/HD UPDATE POSITION MAY BE DELAYED TO ANY HD FALLING EDGE IN THE FIELD USING THE UPDATE REGISTER.
Figure 3a. Serial Write Operation
DATA FOR STARTING
REGISTER ADDRESS
SDATA
A0
A1
A2
A3
A4
A5
A6
A7
D0
D1
D2
D3
D4
DATA FOR NEXT
REGISTER ADDRESS
D5
D0
D1
D2
D3
D4
D5
D0
D1
D2
...
...
SCK
...
SL
NOTES
1. MULTIPLE SEQUENTIAL REGISTERS MAY BE LOADED CONTINUOUSLY.
2. THE FIRST (LOWEST ADDRESS) REGISTER ADDRESS IS WRITTEN, FOLLOWED BY MULTIPLE 6-BIT DATA WORDS.
3. THE ADDRESS WILL AUTOMATICALLY INCREMENT WITH EACH 6-BIT DATA WORD (ALL 6 BITS MUST BE WRITTEN).
4. SL IS HELD LOW UNTIL THE LAST DESIRED REGISTER HAS BEEN LOADED.
5. NEW DATA IS UPDATED AT EITHER THE SL RISING EDGE, OR AT THE HD FALLING EDGE AFTER THE NEXT VD FALLING EDGE.
Figure 3b. Continuous Serial Write Operation
COMPLETE REGISTER LISTING
Table I
Register
Description
Register
Description
oprmode
ctlmode
preventpdate
readback
vdhdpol
fieldval
hblkretime
tgcore_rstb
h12pol
h1posloc
h1negloc
AFE Operation Modes
AFE Control Modes
Prevents Loading of VD-Updated Registers
Enables Serial Register Readback Mode
VD/HD Active Polarity
Internal Field Pulse Value
Retimes the H1 hblk to Internal Clock
Reset Bar Signal for Internal TG Core
H1/H2 Polarity Control
H1 Positive Edge Location
H1 Negative Edge Location
h1drv
h2drv
h3drv
h4drv
rgpol
rgposloc
rgnegloc
rgdrv
shpposloc
shdposloc
H1 Drive Current
H2 Drive Current
H3 Drive Current
H4 Drive Current
RG Polarity
RG Positive Edge Location
RG Negative Edge Location
RG Drive Current
SHP Sample Location
SHD Sample Location
Notes on Register Listing:
1. All addresses and default values are expressed in Hexadecimal.
2. All registers are VD/HD updated as shown in Figure 3, except for the above-listed registers that are SL updated.
–12–
REV. 0
AD9848/AD9849
Notes about Accessing a Double-Wide Register
There are many double-wide registers in the AD9848/AD9849, for example: oprmode, clpdmtog1_0, clpdmscp3, etc. These registers are configured into two consecutive 6-bit registers with the least significant six bits located in the lower of the two addresses and
the remaining most significant bits located in the higher of the two addresses. For example, the 6 LSBs of the clpdmscp3 register, clpdmscp3[5:0], are located at address 0x81. The most significant six bits of the clpdmscp3 register, clpdmscp3[11:6], are
located at address 0x82. The following rules must be followed when accessing double-wide registers:
1. When accessing a double-wide register, BOTH addresses must be written to.
2. The lower of the two consecutive addresses for the double-wide register must be written to first. In the example of the clpdmscp3
register, the contents of address 0x81 must be written first followed by the contents of address 0x82. The register will be updated
after the completion of the write to register 0x82, either at the next SL rising edge or next VD/HD falling edge.
3. A single write to the lower of the two consecutive addresses of a double-wide register that is not followed by a write to the higher
address of the registers, is not permitted. This will not update the register.
4. A single write to the higher of the two consecutive addresses of a double-wide register that is not preceded by a write to the lower
of the two address, is not permitted. Although the write to the higher address will update the full double-wide register, the lower
six bits of the register will be written with an indeterminate value if the lower address was not written first.
Address
Bit
Content
Width
Default
Value
Register Name
AFE Registers
00
01
02
03
04
05
06
07
08
09
0A
[5:0]
[1:0]
[5:0]
[3:0]
[5:0]
[1:0]
[5:0]
[5:0]
[5:0]
[5:0]
[5:0]
6
2
6
4
6
2
6
6
6
6
6
00
00
16
02
00
02
00
00
00
00
00
Miscellaneous/Extra
# Bits
56
oprmode[5:0]
oprmode[7:6]
ccdgain[5:0]
ccdgain[9:6]
refblack[5:0]
refblack[7:6]
ctlmode
pxga gain0
pxga gain1
pxga gain2
pxga gain3
AFE Operation Mode (See AFE Register Breakdown)
# Bits
26
Output Control (0 = Make All Outputs DC Inactive)
Serial Data Update Control (Sets the line within the field
for serial data update to occur.)
Prevent the Update of the “VD/HD Updated” Registers
Serial Interface Readback Enable
DOUT Phase Control
Disable CCDIN DC Restore Circuit During PBLK
(1 = Disable)
VD/HD Active Polarity (0 = Low Active, 1 = High Active)
Internal Field Pulse Value (0 = Next Field Odd,
1 = Next Field Even)
Re-Sync hblk to h1 Clock
Addresses 20 to 25 Reserved for Internal Test Modes
TG Core Reset_Bar (0 = Hold TG Core in Reset,
1 = Resume Normal Operation)
VGA Gain
Black Clamp Level
Control Mode (See AFE Register Breakdown)
PxGA Color 0 Gain
PxGA Color 1 Gain
PxGA Color 2 Gain
PxGA Color 3 Gain
16
17
18
19
1A
1B
1C
[0]
[5:0]
[5:0]
[0]
[0]
[5:0]
[0]
1
6
6
1
1
6
1
00
00
00
00
00
00
00
out_cont
update[5:0]
update[11:6]
preventupdate
readback
doutphase
disablerestore
1D
1E
[0]
[0]
1
1
00
01
vdhdpol
fieldval
1F
20
26
[0]
1
00
[0]
1
00
hblkretime
internal test mode
tgcore_rstb
REV. 0
Register Description
–13–
AD9848/AD9849
Address
Bit
Content
Width
Default
Value
Register Name
CLPDM
Register Description
# Bits
146
CLPDM Internal/External (0 = Internal, 1 = External)
CLPDM External Active Polarity (0 = Low Active,
1 = High Active)
Sequence #0: Start Polarity for CLPDM
Sequence #0: Toggle Position 1 for CLPDM
64
65
[0]
[0]
1
1
01
00
clpdmdir
clpdmpol
66
67
68
69
6A
6B
6C
6D
6E
6F
70
71
72
73
74
75
76
77
78
79
[0]
[5:0]
[5:0]
[5:0]
[5:0]
[0]
[5:0]
[5:0]
[5:0]
[5:0]
[0]
[5:0]
[5:0]
[5:0]
[5:0]
[0]
[5:0]
[5:0]
[5:0]
[5:0]
7A
7B
7C
7D
7E
7F
80
81
82
83
[1:0]
[5:0]
[5:0]
[1:0]
[5:0]
[5:0]
[1:0]
[5:0]
[5:0]
[1:0]
1
6
6
6
6
1
6
6
6
6
1
6
6
6
6
1
6
6
6
6
0
2
6
6
2
6
6
2
6
6
2
01
2C
00
35
00
01
3E
02
16
03
00
3F
3F
3F
3F
01
3F
3F
3F
3F
00
00
3F
3F
00
3F
3F
00
3F
3F
00
clpdmspol0
clpdmtog1_0[5:0]
clpdmtog1_0[11:6]
clpdmtog2_0[5:0]
clpdmtog2_0[11:6]
clpdmspol1
clpdmtog1_1[5:0]
clpdmtog1_1[11:6]
clpdmtog2_1[5:0]
clpdmtog2_1[11:6]
clpdmspol2
clpdmtog1_2[5:0]
clpdmtog1_2[11:6]
clpdmtog2_2[5:0]
clpdmtog2_2[11:6]
clpdmspol3
clpdmtog1_3[5:0]
clpdmtog1_3[11:6]
clpdmtog2_3[5:0]
clpdmtog2_3[11:6]
clpdmscp0
clpdmsptr0
clpdmscp1[5:0]
clpdmscp1[11:6]
clpdmsptr1
clpdmscp2[5:0]
clpdmscp2[11:6]
clpdmsptr2
clpdmscp3[5:0]
clpdmscp3[11:6]
clpdmsptr3
–14–
Sequence #0: Toggle Position 2 for CLPDM
Sequence #1: Start Polarity for CLPDM
Sequence #1: Toggle Position 1 for CLPDM
Sequence #1: Toggle Position 2 for CLPDM
Sequence #2: Start Polarity for CLPDM
Sequence #2: Toggle Position 1 for CLPDM
Sequence #2: Toggle Position 2 for CLPDM
Sequence #3: Start Polarity for CLPDM
Sequence #3: Toggle Position 1 for CLPDM
Sequence #3: Toggle Position 2 for CLPDM
CLPDM Sequence-Change-Position #0 (Hardcoded to 0)
CLPDM Sequence Pointer for SCP #0
CLPDM Sequence-Change-Position #1
CLPDM Sequence Pointer for SCP #1
CLPDM Sequence-Change-Position #2
CLPDM Sequence Pointer for SCP #2
CLPDM Sequence-Change-Position #3
CLPDM Sequence Pointer for SCP #3
REV. 0
AD9848/AD9849
Address
Bit
Content
Width
Default
Value
Register Name
CLPOB
# Bits
146
CLPOB Internal/External (0 = Internal, 1 = External)
CLPOB External Active Polarity (0 = Low Active,
1 = High Active)
Sequence #0: Start Polarity for CLPOB
Sequence #0: Toggle Position 1 for CLPOB
84
85
[0]
[0]
1
1
01
00
clpobdir
clpobpol
86
87
88
89
8A
8B
8C
8D
8E
8F
90
91
92
93
94
95
96
97
98
99
[0]
[5:0]
[5:0]
[5:0]
[5:0]
[0]
[5:0]
[5:0]
[5:0]
[5:0]
[0]
[5:0]
[5:0]
[5:0]
[5:0]
[0]
[5:0]
[5:0]
[5:0]
[5:0]
9A
9B
9C
9D
9E
9F
A0
A1
A2
A3
[1:0]
[5:0]
[5:0]
[1:0]
[5:0]
[5:0]
[1:0]
[5:0]
[5:0]
[1:0]
1
6
6
6
6
1
6
6
6
6
1
6
6
6
6
1
6
6
6
6
0
2
6
6
2
6
6
2
6
6
2
01
0E
00
2B
00
01
2B
06
3F
3F
00
3F
3F
3F
3F
01
3F
3F
3F
3F
00
03
01
00
01
02
00
00
37
03
03
clpobpol0
clpobtog1_0[5:0]
clpobtog1_0[11:6]
clpobtog2_0[5:0]
clpobtog2_0[11:6]
clpobpol1
clpobtog1_1[5:0]
clpobtog1_1[11:6]
clpobtog2_1[5:0]
clpobtog2_1[11:6]
clpobspol2
clpobtog1_2[5:0]
clpobtog1_2[11:6]
clpobtog2_2[5:0]
clpobtog2_2[11:6]
clpobspol3
clpobtog1_3[5:0]
clpobtog1_3[11:6]
clpobtog2_3[5:0]
clpobtog2_3[11:6]
clpobscp0
clpobsptr0
clpobscp1[5:0]
clpobscp1[11:6]
clpobsptr1
clpobscp2[5:0]
clpobscp2[11:6]
clpobsptr2
clpobscp3[5:0]
clpobscp3[11:6]
clpobsptr3
REV. 0
Register Description
–15–
Sequence #0: Toggle Position 2 for CLPOB
Sequence #1: Start Polarity for CLPOB
Sequence #1: Toggle Position 1 for CLPOB
Sequence #1: Toggle Position 2 for CLPOB
Sequence #2: Start Polarity for CLPOB
Sequence #2: Toggle Position 1 for CLPOB
Sequence #2: Toggle Position 2 for CLPOB
Sequence #3: Start Polarity for CLPOB
Sequence #3: Toggle Position 1 for CLPOB
Sequence #3: Toggle Position 2 for CLPOB
CLPOB Sequence-Change-Position #0 (Hardcoded to 0)
CLPOB Sequence Pointer for SCP #0
CLPOB Sequence-Change-Position #1
CLPOB Sequence Pointer for SCP #1
CLPOB Sequence-Change-Position #2
CLPOB Sequence Pointer for SCP #2
CLPOB Sequence-Change-Position #3
CLPOB Sequence Pointer for SCP #3
AD9848/AD9849
Address
Bit
Content
Width
Default
Value
Register Name
HBLK
Register Description
# Bits
147
HBLK Internal/External (0 = Internal, 1 = External)
HBLK External Active Polarity (0 = Low Active,
1 = High Active)
HBLK External Masking Polarity (0 = Mask H1 and H3 Low,
1 = Mask H1 and H3 High)
Sequence #0: Masking Polarity for HBLK
Sequence #0: Toggle High Position for HBLK
A4
A5
[0]
[0]
1
1
01
00
hblkdir
hblkpol
A6
[0]
1
01
hblkextmask
A7
A8
A9
AA
AB
AC
AD
AE
AF
B0
B1
B2
B3
B4
B5
B6
B7
B8
B9
BA
[0]
[5:0]
[5:0]
[5:0]
[5:0]
[0]
[5:0]
[5:0]
[5:0]
[5:0]
[0]
[5:0]
[5:0]
[5:0]
[5:0]
[0]
[5:0]
[5:0]
[5:0]
[5:0]
BB
BC
BD
BE
BF
C0
C1
C2
C3
C4
[1:0]
[5:0]
[5:0]
[1:0]
[5:0]
[5:0]
[1:0]
[5:0]
[5:0]
[1:0]
1
6
6
6
6
1
6
6
6
6
1
6
6
6
6
1
6
6
6
6
0
2
6
6
2
6
6
2
6
6
2
01
3E
00
0D
06
01
38
00
3C
02
00
3F
3F
3F
3F
01
3F
3F
3F
3F
00
00
3F
3F
00
3F
3F
00
3F
3F
00
hblkmask0
hblktog1_0[5:0]
hblktog1_0[11:6]
hblkbtog2_0[5:0]
hblkbtog2_0[11:6]
hblkmask1
hblktog1_1[5:0]
hblktog1_1[11:6]
hblktog2_1[5:0]
hblktog2_1[11:6]
hblkmask2
hblktog1_2[5:0]
hblktog1_2[11:6]
hblktog2_2[5:0]
hblktog2_2[11:6]
hblkmask3
hblktog1_3[5:0]
hblktog1_3[11:6]
hblktog2_3[5:0]
hblktog2_3[11:6]
hblkscp0
hblksptr0
hblkscp1[5:0]
hblkscp1[11:6]
hblksptr1
hblkscp2[5:0]
hblkscp2[11:6]
hblksptr2
hblkscp3[5:0]
hblkscp3[11:6]
hblksptr3
–16–
Sequence #0: Toggle Low Position for HBLK
Sequence #1: Masking Polarity for HBLK
Sequence #1: Toggle High Position for HBLK
Sequence #1: Toggle Low Position for HBLK
Sequence #2: Masking Polarity for HBLK
Sequence #2: Toggle High Position for HBLK
Sequence #2: Toggle Low Position for HBLK
Sequence #3: Masking Polarity for HBLK
Sequence #3: Toggle High Position for HBLK
Sequence #3: Toggle Low Position for HBLK
HBLK Sequence-Change-Position #0 (Hardcoded to 0)
HBLK Sequence Pointer for SCP #0
HBLK Sequence-Change-Position #1
HBLK Sequence Pointer for SCP #1
HBLK Sequence-Change-Position #2
HBLK Sequence Pointer for SCP #2
HBLK Sequence-Change-Position #3
HBLK Sequence Pointer for SCP #3
REV. 0
AD9848/AD9849
Address
Bit
Content
Width
Default
Value
Register Name
PBLK
# Bits
146
PBLK Internal/External (0 = Internal, 1 = External)
PBLK External Active Polarity (0 = Low Active,
1 = High Active)
Sequence #0: Start Polarity for PBLK
Sequence #0: Toggle Position 1 for PBLK
C5
C6
[0]
[0]
1
1
01
00
pblkdir
pblkpol
C7
C8
C9
CA
CB
CC
CD
CE
CF
D0
D1
D2
D3
D4
D5
D6
D7
D8
D9
DA
[0]
[5:0]
[5:0]
[5:0]
[5:0]
[0]
[5:0]
[5:0]
[5:0]
[5:0]
[0]
[5:0]
[5:0]
[5:0]
[5:0]
[0]
[5:0]
[5:0]
[5:0]
[5:0]
DB
DC
DD
DE
DF
E0
E1
E2
E3
E4
[1:0]
[5:0]
[5:0]
[1:0]
[5:0]
[5:0]
[1:0]
[5:0]
[5:0]
[1:0]
1
6
6
6
6
1
6
6
6
6
1
6
6
6
6
1
6
6
6
6
0
2
6
6
2
6
6
2
6
6
2
01
3D
00
2A
06
00
2A
06
3F
3F
00
3F
3F
3F
3F
01
3F
3F
3F
3F
00
02
01
00
01
02
00
00
37
03
02
pblkspol0
pblktog1_0[5:0]
pblktog1_0[11:6]
pblkbtog2_0[5:0]
pblkbtog2_0[11:6]
pblkspol1
pblktog1_1[5:0]
pblktog1_1[11:6]
pblktog2_1[5:0]
pblktog2_1[11:6]
pblkspol2
pblktog1_2[5:0]
pblktog1_2[11:6]
pblktog2_2[5:0]
pblktog2_2[11:6]
pblkspol3
pblktog1_3[5:0]
pblktog1_3[11:6]
pblktog2_3[5:0]
pblktog2_3[11:6]
pblkscp0
pblksptr0
pblkscp1[5:0]
pblkscp1[11:6]
pblksptr1
pblkscp2[5:0]
pblkscp2[11:6]
pblksptr2
pblkscp3[5:0]
pblkscp3[11:6]
pblksptr3
H1–H4, RG, SHP, SHD
Sequence #0: Toggle Position 2 for PBLK
Sequence #1: Start Polarity for PBLK
Sequence #1: Toggle Position 1 for PBLK
Sequence #1: Toggle Position 2 for PBLK
Sequence #2: Start Polarity for PBLK
Sequence #2: Toggle Position 1 for PBLK
Sequence #2: Toggle Position 2 for PBLK
Sequence #3: Start Polarity for PBLK
Sequence #3: Toggle Position 1 for PBLK
Sequence #3: Toggle Position 2 for PBLK
PBLK Sequence-Change-Position #0 (hardcoded to 0)
PBLK Sequence Pointer for SCP #0
PBLK Sequence-Change-Position #1
PBLK Sequence Pointer for SCP #1
PBLK Sequence-Change-Position #2
PBLK Sequence Pointer for SCP #2
PBLK Sequence-Change-Position #3
PBLK Sequence Pointer for SCP #3
# Bits
53
H1/H2 Polarity Control (0 = No Inversion, 1 = Inversion)
H1 Positive Edge Location
H1 Negative Edge Location
H1 Drive Strength (0 = OFF, 1 = 3.5 mA, 2 = 7 mA,
3 = 10.5 mA, 4 = 14 mA, 5 = 17.5 mA, 6 = 21 mA,
7 = 24.5 mA)
H2 Drive Strength
H3 Drive Strength
H4 Drive Strength
RG Polarity Control (0 = No Inversion, 1 = Inversion)
RG Positive Edge Location
RG Negative Edge Location
RG Drive Strength (0 = OFF, 1 = 3.5 mA, 2 = 7 mA, 3 =
10.5 mA, 4 = 14 mA, 5 = 17.5 mA, 6 = 21 mA, 7 = 24.5 mA)
SHP (Positive) Edge Sampling Location
SHD (Positive) Edge Sampling Location
E5
E6
E7
E8
[0]
[5:0]
[5:0]
[2:0]
1
6
6
3
00
00
20
03
h1pol
h1posloc
h1negloc
h1drv
E9
EA
EB
EC
ED
EE
EF
[2:0]
[2:0]
[2:0]
[0]
[5:0]
[5:0]
[2:0]
3
3
3
1
6
6
3
03
03
03
00
00
10
02
h2drv
h3drv
h4drv
rgpol
rgposloc
rgnegloc
rgdrv
F0
F1
[5:0]
[5:0]
6
6
24
00
shpposloc
shdposloc
REV. 0
Register Description
–17–
AD9848/AD9849
Address
Bit
Content
Width
Default
Value
Register Name
Register Description
8'h0
Serial Address:
8'h00 {oprmode[5:0]}, 8'h01 {oprmode[7:6]}
AFE REGISTER BREAKDOWN
oprmode
[7:0]
[1:0]
2'h0
2'h1
2'h2
2'h3
powerdown[1:0]
[2]
[3]
[4]
[5]
[6]
[7]
ctlmode
disblack
test mode
test mode
test mode
test mode
test mode
[5:0]
[2:0]
[3]
[4]
[5]
6'h0
3'h0
3'h1
3'h2
3'h3
3'h4
3'h5
3'h6
3'h7
1'h0
1'h1
1'h0
1'h1
Full Power
Fast Recovery
Reference Standby
Total Shutdown
Disable Black Loop Clamping (HI Active)
Test Mode—Should Be Set LOW
Test Mode—Should Be Set HIGH
Test Mode—Should Be Set LOW
Test Mode—Should Be Set LOW
Test Mode—Should Be Set LOW
Serial Address: 8'h06 {cltmode[5:0]}
ctlmode[2:0]
Off
Mosaic Separate
VD Selected/Mosaic Interlaced
Mosaic Repeat
Three-Color
Three-Color II
Four-Color
Four-Color II
Enable PxGA (HI Active)
Latch Output Data on Selected DOUT Edge
Leave Output Latch Transparent
ADC Outputs are Driven
ADC Outputs are Three-Stated
enablepxga
outputlat
tristateout
–18–
REV. 0
AD9848/AD9849
PRECISION TIMING HIGH-SPEED TIMING
GENERATION
High Speed Clock Programmability
Figure 5 shows how the high-speed clocks RG, H1–H4, SHP,
and SHD are generated. The RG pulse has programmable rising
and falling edges, and may be inverted using the polarity control.
The horizontal clocks H1 and H3 have programmable rising and
falling edges, and polarity control. The H2 and H4 clocks are
always inverses of H1 and H3 respectively. Table II summarizes
the high-speed timing registers and their parameters.
The AD9848 and AD9849 generate flexible high-speed timing
signals using the Precision Timing core. This core is the foundation for generating the timing used for both the CCD and the
AFE; the reset gate RG, horizontal drivers H1–H4, and the
SHP/SHD sample clocks. A unique architecture makes it
routine for the system designer to optimize image quality, by
providing precise control over the horizontal CCD readout
and the AFE correlated double sampling.
Timing Resolution
The Precision Timing core uses a 1X master clock input (CLI) as
a reference. This clock should be the same as the CCD pixel
clock frequency. Figure 4 illustrates how the internal timing core
divides the master clock period into 48 steps or edge positions.
Therefore, the edge resolution of the Precision Timing core is
(tCLI/48). For more information on using the CLI input, see the
Application Information section.
POSITION
The edge location registers are 6 bits wide, but there are only
48 valid edge locations available. Therefore, the register values
are mapped into four quadrants, with each quadrant containing
12 edge locations. Table III shows the correct register values
for the corresponding edge locations. Figure 6 shows the range
and default locations of the high-speed clock signals.
P[12]
P[0]
P[24]
P[36]
P[48]=P[0]
CLI
...
tCLIDLY
...
1 PIXEL
PERIOD
NOTES
1. PIXEL CLOCK PERIOD IS DIVIDED INTO 48 POSITIONS, PROVIDING FINE EDGE RESOLUTION FOR HIGH-SPEED CLOCKS.
2. THERE IS A FIXED DELAY FROM THE CLI INPUT TO THE INTERNAL PIXEL PERIOD POSITIONS (tCLIDLY = 6 ns TYP).
Figure 4. High-Speed Clock Resolution From CLI Master Clock Input
(3)
(4)
CCD SIGNAL
(1)
(2)
RG
(5)
(6)
H1/H3
H2/H4
NOTES
PROGRAMMABLE CLOCK POSITIONS:
(1) RG RISING EDGE AND (2) FALLING EDGE
(3) SHP AND (4) SHD SAMPLE LOCATION
(5) H1/H3 RISING EDGE POSITION AND (6) FALLING EDGE POSITION (H2/H4 ARE INVERSE OF H1/H3)
Figure 5. High-Speed Clock Programmable Locations
REV. 0
–19–
AD9848/AD9849
H-Driver and RG Outputs
In addition to the programmable timing positions, the AD9848/
AD9849 features on-chip output drivers for the RG and H1–H4
outputs. These drivers are powerful enough to directly drive the
CCD inputs. The H-driver current can be adjusted for optimum
rise/fall time into a particular load by using the DRV registers. The
RG drive current is adjustable using the RGDRV register. Each
3-bit DRV register is adjustable in 3.5 mA increments, with the
minimum setting of 0 equal to OFF or three-state, and the maximum setting of 7 equal to 24.5 mA.
As shown in Figure 7, the H2/H4 outputs are inverses of H1/
H3. The internal propagation delay resulting from the signal
inversion is less than l ns, which is significantly less than the
typical rise time driving the CCD load. This results in a H1/H2
crossover voltage at approximately 50% of the output swing.
The crossover voltage is not programmable.
Digital Data Outputs
The AD9848/AD9849 data output phase is programmable
using the DOUTPHASE register. Any edge from 0 to 47 may
be programmed, as shown in Figure 8.
Table II. H1–H4, RG, SHP, SHD Timing Parameters
Register Name
Length
Range
Description
POL
POSLOC
1b
6b
High/Low
0–47 Edge Location
NEGLOC
DRV
6b
3b
0–47 Edge Location
0–7 Current Steps
Polarity Control for H1, H3, and RG (0 = No Inversion, 1 = Inversion)
Positive Edge Location for H1, H3, and RG
Sample Location for SHP, SHD
Negative Edge Location for H1, H3, and RG
Drive Current for H1–H4 and RG Outputs (3.5 mA Per Step)
Table III. Precision Timing Edge Locations
Quadrant
Edge Location (Decimal)
Register Value (Decimal)
Register Value (Binary)
I
II
III
IV
0 to 11
12 to 23
24 to 35
36 to 47
0 to 11
16 to 27
32 to 43
48 to 59
000000 to 001011
010000 to 011011
100000 to 101011
110000 to 111011
POSITION
P[0]
P[24]
P[12]
P[48] = P[0]
P[36]
PIXEL
PERIOD
RGr[0]
RGf[12]
RG
Hr[0]
Hf[24]
H1/H3
SHP[28]
SHD[48]
tS1
CCD SIGNAL
NOTES
1. ALL SIGNAL EDGES ARE FULLY PROGRAMMABLE TO ANY OF THE 48 POSITIONS WITHIN ONE PIXEL PERIOD.
2. DEFAULT POSITIONS FOR EACH SIGNAL ARE SHOWN ABOVE.
Figure 6. High-Speed Clock Default and Programmable Locations
–20–
REV. 0
AD9848/AD9849
tRISE
H1/H3
H2/H4
tPD << tRISE
tPD
H1/H3
H2/H4
FIXED CROSSOVER VOLTAGE
Figure 7. H-Clock Inverse Phase Relationship
P[12]
P[0]
P[24]
P[36]
P[48] = P[0]
CLI
1 PIXEL PERIOD
tOD
DOUT
NOTES
1. DIGITAL OUTPUT DATA (DOUT) PHASE IS ADJUSTABLE WITH RESPECT TO THE PIXEL PERIOD.
2. WITHIN 1 CLOCK PERIOD, THE DATA TRANSITION CAN BE PROGRAMMED TO ANY OF THE 48 LOCATIONS.
Figure 8. Digital Output Phase Adjustment
REV. 0
–21–
AD9848/AD9849
HORIZONTAL CLAMPING AND BLANKING
The AD9848/AD9849’s horizontal clamping and blanking
pulses are fully programmable to suit a variety of applications.
As with the vertical timing generation, individual sequences are
defined for each signal, which are then organized into multiple
regions during image readout. This allows the dark pixel clamping and blanking patterns to be changed at each stage of the
readout, in order to accommodate different image transfer timing and high-speed line shifts.
Individual CLPOB, CLPDM, and PBLK Sequences
The AFE horizontal timing consists of CLPOB, CLPDM, and
PBLK, as shown in Figure 9. These three signals are independently programmed using the registers in Table IV. SPOL is the
start polarity for the signal, and TOG1 and TOG2 are the first
and second toggle positions of the pulse. All three signals are
active low, and should be programmed accordingly. Up to four
individual sequences can be created for each signal.
Individual HBLK Sequences
The HBLK programmable timing shown in Figure 10 is similar
to CLPOB, CLPDM, PBLK. However, there is not start polarity control. Only the toggle positions are used, to designate the
start and the stop positions of the blanking period. Additionally,
there is a polarity control HBLKMASK which designates the
polarity of the horizontal clock signals H1 – H4 during the blanking period. Setting HBLKMASK high will set H1 = H3 = low
and H2 = H4 = high during the blanking, as shown in Figure
11. Up to four individual sequences are available for HBLK.
...
HD
(2)
CLPOB
CLPDM (1)
PBLK
...
(3)
CLAMP
CLAMP
NOTES
PROGRAMMABLE SETTINGS:
(1) START POLARITY (CLAMP AND BLANK REGION ARE ACTIVE LOW)
(2) FIRST TOGGLE POSITION
(3) SECOND TOGGLE POSITION
Figure 9. Clamp and Preblank Pulse Placement
...
HD
...
(2)
(1)
BLANK
HBLK
BLANK
NOTES
PROGRAMMABLE SETTINGS:
(1) FIRST TOGGLE POSITION = START OF BLANKING
(2) SECOND TOGGLE POSITION = END OF BLANKING
Figure 10. Horizontal Blanking (HBLK) Pulse Placement
Table IV. CLPOB, CLPDM, PBLK Individual Sequence Parameters
Register Name
Length
Range
Description
SPOL
TOG1
TOG2
1b
12b
12b
High/Low
0–4095 Pixel Location
0–4095 Pixel Location
Starting Polarity of Clamp and Blanking Pulses for Sequences 0–3
First Toggle Position within the Line for Sequences 0–3
Second Toggle Position within the Line for Sequences 0–3
Table V. HBLK Individual Sequence Parameters
Register Name
Length
Range
Description
HBLKMASK
HBLKTOG1
HBLKTOG2
1b
12b
12b
High/Low
0–4095 Pixel Location
0–4095 Pixel Location
Masking Polarity for H1 for Sequences 0–3 (0 = H1 Low, 1 = H1 High)
First Toggle Position within the Line for Sequences 0–3
Second Toggle Position within the Line for Sequences 0–3
–22–
REV. 0
AD9848/AD9849
Horizontal Sequence Control
The AD9848/AD9849 uses Sequence Change Positions (SCP)
and Sequence Pointers (SPTR) to organize the individual horizontal sequences. Up to four SCPs are available to divide the
readout into four separate regions, as shown in Figure 12.
The SCP 0 is always hard-coded to line 0, and SCP1–3 are register programmable. During each region bounded by the SCP, the
SPTR registers designate which sequence is used by each signal.
CLPOB, CLPDM, PBLK, and HBLK each have a separate
set of SCP. For example, CLPOBSCP1 will define Region 0
for CLPOB, and in that region any of the four individual
CLPOB sequences may be selected with the CLPOBSPTR
registers. The next SCP defines a new region, and in that
region each signal can be assigned to a different individual
sequence. The Sequence Control Registers are summarized
in Table VI.
...
HD
...
HBLK
H1/H3
THE POLARITY OF H1 DURING BLANKING IS PROGRAMMABLE (H2 IS OPPOSITE POLARITY OF H1)
...
H1/H3
H2/H4
...
Figure 11. HBLK Masking Control
SEQUENCE CHANGE OF POSITION #0
(V-COUNTER = 0)
SINGLE FIELD (1 VD INTERVAL)
CLAMP AND PBLK SEQUENCE REGION 0
SEQUENCE CHANGE OF POSITION #1
CLAMP AND PBLK SEQUENCE REGION 1
SEQUENCE CHANGE OF POSITION #2
CLAMP AND PBLK SEQUENCE REGION 2
SEQUENCE CHANGE OF POSITION #3
CLAMP AND PBLK SEQUENCE REGION 3
NOTE
UP TO FOUR INDIVIDUAL HORIZONTAL CLAMP AND BLANKING REGIONS MAY BE
PROGRAMMED WITHIN A SINGLE FIELD, USING THE SEQUENCE CHANGE POSITIONS.
Figure 12. Clamp and Blanking Sequence Flexibility
Table VI. Horizontal Sequence Control Parameters for CLPOB, CLPDM, PBLK, and HBLK
Register Name
Length
Range
Description
SCP1–SCP3
SPTR0–SPTR3
12b
2b
0–4095 Line Number
0–3 Sequence Number
CLAMP/BLANK SCP to Define Horizontal Regions 0–3
Sequence Pointer for Horizontal Regions 0–3
REV. 0
–23–
AD9848/AD9849
H-Counter Synchronization
The H-Counter reset occurs on the sixth CLI rising edge following the HD falling edge. The PxGA steering is synchronized
with the reset of the internal H-Counter. (See Figure 13.)
VD
3ns MIN
HD
H-COUNTER
RESET
3ns MIN
CLI
H-COUNTER X
(PIXEL COUNTER)
X
X
X
X
X
X
X
0
1
2
3
4
5
6
7
8
9
10
11
12
14
15
0
1
2
3
4
5
PxGA GAIN
REGISTER X
X
X
X
X
X
X
X
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
2
3
2
3
2
3
NOTES
1. INTERNAL H-COUNTER IS RESET ON THE SIXTH CLI RISING EDGE FOLLOWING THE HD FALLING EDGE.
2. PxGA STEERING IS SYNCRONIZED WITH THE RESET OF THE INTERNAL H-COUNTER (MOSAIC SEPARATE MODE IS SHOWN).
3. VD FALLING EDGE SHOULD OCCUR ONE CLOCK CYCLE BEFORE HD FALLING EDGE FOR PROPER PxGA LINE SYNCHRONIZATION.
Figure 13. H-Counter Synchronization
–24–
REV. 0
AD9848/AD9849
POWER-UP PROCEDURE
VDD
(INPUT)
CLI
(INPUT)
tPWR
SERIAL
WRITES
1V
...
...
VD
(OUTPUT)
ODD FIELD
EVEN FIELD
1H
...
...
HD
(OUTPUT)
H2/H4
DIGITAL
OUTPUTS
H1/H3, RG
CLOCKS ACTIVE WHEN OUT_CONT REGISTER IS
UPDATED AT VD/HD EDGE
Figure 14. Recommended Power-Up Sequence
Recommended Power-Up Sequence
When the AD9848 and AD9849 are powered up, the following sequence is recommended (refer to Figure 14 for each step).
1. Turn on power supplies for AD9848/AD9849.
2. Apply the master clock input CLI, VD, and HD.
3. The Precision Timing core must be reset by writing a “0” to the TGCORE_RSTB register (addr x026) followed by writing
a “l” to the TGCORE_RSTB register. This will start the internal timing core operation.
4. Write a “1” to the PREVENTUPDATE register (addr x01B). This will prevent the updating of the serial register data.
5. Write to desired registers to configure high speed timing and horizontal timing.
6. Write a “1” to the OUT_CONT register (addr x016). This will allow the outputs to become active after the next VD/HD
rising edge.
7. Write a “0” to the PREVENTUPDATE register (addr x01B). This will allow the serial information to be updated at next
VD/HD falling edge.
8. The next VD/HD falling edge allows register updates to occur, including OUT_CONT, which enables all clock outputs.
REV. 0
–25–
AD9848/AD9849
ANALOG FRONT END DESCRIPTION AND OPERATION
advantage of removing this offset at the input stage is to maximize system headroom. Some area CCDs have large black
level offset voltages, which, if not corrected at the input stage,
can significantly reduce the available headroom in the internal circuitry when higher VGA gain settings are used.
The AD9848/AD9849 signal processing chain is shown in
Figure 15. Each processing step is essential in achieving a highquality image from the raw CCD pixel data.
DC Restore
To reduce the large dc offset of the CCD output signal, a dc
restore circuit is used with an external 0.1 µF series coupling
capacitor. This restores the dc level of the CCD signal to
approximately 1.5 V, to be compatible with the 3 V analog
supply signal of the AD9848/AD9849.
Horizontal timing examples are shown on the last page of the
“Applications Information” section. It is recommended that the
CLPDM pulse be used during valid CCD dark pixels. CLPDM
may be used during the optical black pixels, either together with
CLPOB or separately. The CLPDM pulse should be a minimum
of four pixels wide.
Correlated Double Sampler
The CDS circuit samples each CCD pixel twice to extract the
video information and reject low-frequency noise. The timing
shown in Figure 6 illustrates how the two internally generated
CDS clocks, SHP and SHD, are used to sample the reference
level and data level of the CCD signal respectively. The placement of the SHP and SHD sampling edges is determined by
the setting of the SHPPOSLOC and SHDPOSLOC registers
located at addr. 0xF0 and 0xF1 respectively. Placement of
these two clock signals is critical in achieving the best performance from the CCD.
PxGA
The PxGA provides separate gain adjustment for the individual
color pixels. A programmable gain amplifier with four separate
values, the PxGA has the capability to “multiplex” its gain value
on a pixel-to-pixel basis (see Figure 17). This allows lower output color pixels to be gained up to match higher output color
pixels. Also, the PxGA may be used to adjust the colors for
white balance, reducing the amount of digital processing that is
needed. The four different gain values are switched according to
the “Color Steering” circuitry. Seven different color steering
modes for different types of CCD color filter arrays are programmed in the AD9848/AD9849 AFE Register, ctlmode, at
addr. 0x06 (see Figure 16a–16g for timing examples). For
example, Mosaic Separate steering mode accommodates the
popular “Bayer” arrangement of Red, Green, and Blue filters
(see Figure 18).
Input Clamp
A line-rate input clamping circuit is used to remove the CCD’s
optical black offset. This offset exists in the CCD’s shielded black
reference pixels. The AD9848/AD9849 removes this offset in
the input stage to minimize the effect of a gain change on the
system black level, usually called the “gain step.” Another
0.1F
1.0F 1.0F
REFB REFT
CML
INTERNAL
BIASING
DC RESTORE
SHP
CCDIN
SHD
CDS
–2dB TO +10dB
PxGA
CLPDM
INPUT OFFSET
CLAMP
0.1F
0.1F
0.1F
AVDD
2
2.0V
AD9848/AD9849
INTERNAL
VREF
1.5V
0.1F
1.0V
2V FULL SCALE
0dB TO 36dB
10
8-BIT
DAC
10/12
DOUT
OPTICAL BLACK
CLAMP
CLPOB
PBLK
DIGITAL
FILTER
BYP1
8
BYP 2
BYP 3
OUTPUT
DATA
LATCH
10-/12-BIT
ADC
VGA
VGA GAIN
REGISTER
DOUT
PHASE
DOUT
SHP SHD PHASE
CLPDM CLPOB PBLK
CLAMP LEVEL
REGISTER
V-H
TIMING
GENERATION
PRECISION
TIMING
GENERATION
Figure 15. Analog Front-End Block Diagram
–26–
REV. 0
AD9848/AD9849
ODD FIELD
FLD
EVEN FIELD
VD
HD
PxGA GAIN
REGISTER X
X
0
1
0
1
2
3
2
3
0
1
0
1
0
1
0
1
2
3
2
3
0
1
0
1
0
2
3
2
3
0
NOTES
1. VD FALLING EDGE WILL RESET THE PxGA GAIN REGISTER STEERING TO "0101" LINE.
2. HD FALLING EDGES WILL ALTERNATE THE PxGA GAIN REGISTER STEERING BETWEEN "0101" AND "2323" LINES.
3. FLD STATUS IS IGNORED.
Figure 16a. Mosaic Separate Mode
ODD FIELD
FLD
EVEN FIELD
VD
HD
PxGA GAIN X
REGISTER
X
0
1
0
1
0
1
0
1
0
1
0
1
2
3
2
3
2
3
2
3
NOTES
1. FLD FALLING EDGE (START OF ODD FIELD) WILL RESET THE PxGA GAIN REGISTER STEERING TO "0101" LINE.
2. FLD RISING EDGE (START OF EVEN FIELD) WILL RESET THE PxGA GAIN REGISTER STEERING TO "2323" LINE.
3. HD FALLING EDGES WILL RESET THE PxGA GAIN REGISTER STEERING TO EITHER "0" (FLD = ODD) OR "2" (FLD = EVEN).
Figure 16b. Mosaic Interlaced Mode
ODD FIELD
FLD
EVEN FIELD
VD
HD
PxGA GAIN
REGISTER X
X
0
1
0
1
1
2
1
2
0
1
0
1
0
1
0
1
1
2
1
2
0
1
0
1
0
0
1
2
0
0
NOTES
1. VD FALLING EDGE WILL RESET THE PxGA GAIN REGISTER STEERING TO "0101" LINE.
2. HD FALLING EDGES WILL ALTERNATE THE PxGA GAIN REGISTER STEERING BETWEEN "0101" AND "1212" LINES.
3. ALL FIELDS WILL HAVE THE SAME PxGA GAIN STEERING PATTERN (FLD STATUS IS IGNORED).
Figure 16c. Mosaic Repeat Mode
ODD FIELD
FLD
EVEN FIELD
VD
HD
PxGA GAIN
REGISTER X
X
0
1
2
0
0
1
2
0
0
1
2
0
0
1
2
NOTES
1. EACH LINE FOLLOWS "012012" STEERING PATTERN.
2. VD AND HD FALLING EDGES WILL RESET THE PxGA GAIN REGISTER STEERING TO "0".
3. FLD STATUS IS IGNORED.
Figure 16d. Three-Color Mode
REV. 0
–27–
0
0
1
2
0
AD9848/AD9849
ODD FIELD
FLD
EVEN FIELD
VD
HD
PxGA GAIN
REGISTER X
X
0
1
2
0
2
1
0
2
0
1
2
0
0
1
2
0
2
1
0
2
0
1
2
0
0
0
1
2
3
0
0
1
2
3
0
NOTES
1. VD FALLING EDGE WILL RESET THE PxGA GAIN REGISTER STEERING TO "012012" LINE.
2. HD FALLING EDGES WILL ALTERNATE THE PxGA GAIN REGISTER STEERING BETWEEN "012012" AND "210210" LINES.
3. FLD STATUS IS IGNORED.
Figure 16e. Three-Color Mode II
ODD FIELD
FLD
EVEN FIELD
VD
HD
PxGA GAIN
REGISTER X
X
0
1
2
3
0
1
2
3
0
1
2
3
0
1
2
3
0
1
2
3
NOTES
1. EACH LINE FOLLOWS "01230123" STEERING PATTERN.
2. VD AND HD FALLING EDGES WILL RESET THE PxGA GAIN REGISTER STEERING TO GAIN REGISTER "0".
3. FLD STATUS IS IGNORED.
Figure 16f. Four-Color Mode
ODD FIELD
FLD
EVEN FIELD
VD
HD
PxGA GAIN
REGISTER X
X
0
1
2
3
2
3
0
1
0
1
2
3
0
1
2
3
2
3
0
1
NOTES
1. VD FALLING EDGE WILL RESET THE PxGA GAIN REGISTER STEERING TO "01230123" LINE.
2. HD FALLING EDGES WILL ALTERNATE THE PxGA GAIN REGISTER STEERING BETWEEN "01230123" AND "23012301" LINES.
3. FLD STATUS IS IGNORED.
Figure 16g. Four-Color Mode II
–28–
REV. 0
AD9848/AD9849
VD
COLOR
STEERING
CONTROL
HD
SHP/SHD
3
PxGA STEERING
MODE
SELECTION
10
CONTROL
REGISTER
BITS D0–D2
8
2
GAIN1
4:1
MUX
GAIN2
PxGA
CDS
PxGA GAIN
REGISTERS
GAIN3
6
6
PxGA GAIN – dB
GAIN0
4
2
VGA
0
Figure 17. PxGA Block Diagram
CCD: PROGRESSIVE BAYER
–2
32
(100000)
MOSAIC SEPARATE COLOR
STEERING MODE
R
Gr
R
Gr
LINE0
GAIN0, GAIN1, GAIN0, GAIN1...
Gb
B
Gb
B
LINE1
GAIN2, GAIN3, GAIN2, GAIN3...
R
Gr
R
Gr
LINE2
GAIN0, GAIN1, GAIN0, GAIN1...
Gb
B
Gb
B
40
48
58
0
8
16
24
PxGA GAIN REGISTER CODE
31
(011111)
Figure 19. PxGA Gain Curve
Variable Gain Amplifier
Figure 18a. CCD Color Filter Example: Progressive Scan
CCD: INTERLACED BAYER
EVEN FIELD
VD SELECTED COLOR
STEERING MODE
R
Gr
R
Gr
LINE0
GAIN0, GAIN1, GAIN0, GAIN1...
R
Gr
R
Gr
LINE1
GAIN0, GAIN1, GAIN0, GAIN1...
R
Gr
R
Gr
LINE2
GAIN0, GAIN1, GAIN0, GAIN1...
R
Gr
R
Gr
The VGA stage provides a gain range of 2 dB to 36 dB, programmable with 10-bit resolution through the serial digital
interface. Combined with 4 dB from the PxGA stage, the total
gain range for the AD9848/AD9849 is 6 dB to 40 dB. The
minimum gain of 6 dB is needed to match a 1 V input signal
with the ADC full-scale range of 2 V. When compared to 1 V
full-scale systems (such as ADI’s AD9803), the equivalent gain
range is 0 dB to 34 dB.
The VGA gain curve is divided into two separate regions. When
the VGA Gain Register code is between 0 and 511, the curve
follows a (1 + x)/(1 – x) shape, which is similar to a “linear-in-dB”
characteristic. From code 512 to code 1023, the curve follows a
“linear-in-dB” shape. The exact VGA gain can be calculated for
any Gain Register value by using the following two equations:
Code Range Gain Equation (dB)
0 – 511
512 – 1023
Gain = 20 log10 ([658 + code]/[658 – code]) – 0.4
Gain = (0.0354)(code) – 0.04
ODD FIELD
B
Gb
B
LINE0
GAIN2, GAIN3, GAIN2, GAIN3...
Gb
B
Gb
B
LINE1
GAIN2, GAIN3, GAIN2, GAIN3...
Gb
B
Gb
B
LINE2
GAIN2, GAIN3, GAIN2, GAIN3...
Gb
B
Gb
B
36
30
VGA GAIN – dB
Gb
18
12
Figure 18b. CCD Color Filter Example: Interlaced
6
The same Bayer pattern can also be interlaced, and the VD
selected mode should be used with this type of CCD (see
Figure 18b). The Color Steering performs the proper multiplexing of the R, G, and B gain values (loaded into the PxGA
gain registers), and is synchronized by the user with vertical
(VD) and horizontal (HD) sync pulses. For more detailed
information, see the PxGA Timing section. The PxGA gain
for each of the four channels is variable from –2 dB to +10 dB,
controlled in 64 steps through the serial interface. The PxGA
gain curve is shown in Figure 19.
REV. 0
24
0
0
127
255
383
511
639
767
VGA GAIN REGISTER CODE
895
1023
Figure 20. VGA Gain Curve (Gain from PxGA Not
Included)
–29–
AD9848/AD9849
Optical Black Clamp
The optical black clamp loop is used to remove residual offsets in
the signal chain and to track low-frequency variations in the CCD’s
black level. During the optical black (shielded) pixel interval on
each line, the ADC output is compared with a fixed black level
reference, selected by the user in the Clamp Level Register. The
value can be programmed between 0 LSB and 63.75 LSB on the
AD9848, and between 0 LSB and 255 LSB on the AD9849. The
clamp level can be programmed with 8-bit resolution. The resulting error signal is filtered to reduce noise, and the correction value
is applied to the ADC input through a D/A converter. Normally,
the optical black clamp loop is turned on once per horizontal line,
but this loop can be updated more slowly to suit a particular
application. If external digital clamping is used during the post
processing, the AD9848/AD9849 optical black clamping may be
disabled using Bit D2 in the OPRMODE Register. When the loop
is disabled, the Clamp Level Register may still be used to provide
programmable offset adjustment.
The CLPOB pulse should be placed during the CCD’s optical
black pixels. It is recommended that the CLPOB pulse duration
be at least 20 pixels wide to minimize clamp noise. Shorter pulsewidths may be used, but clamp noise may increase, and the ability
to track low-frequency variations in the black level will be reduced.
See the section on Horizontal Clamping and Blanking and also
the Applications Information section for timing examples.
A/D Converter
The AD9848/AD9849 uses high-performance 10-bit/12-bit
ADC architecture, optimized for high speed and low power.
Differential Nonlinearity (DNL) performance is typically better
than 0.5 LSB. The ADC uses a 2 V input range. Better noise
performance results from using a larger ADC full-scale range.
See TPC 1–TPC 4 for typical linearity and noise performance
plots for the AD9848/AD9849.
–30–
REV. 0
AD9848/AD9849
Grounding and Decoupling Recommendations
APPLICATIONS INFORMATION
External Circuit Configuration
As shown in Figure 21, a single ground plane is recommended
for the AD9848/AD9849. This ground plane should be as
continuous as possible, particularly around Pins 25 through 35.
This will ensure that all analog decoupling capacitors provide
the lowest possible impedance path between the power and
bypass pins and their respective ground pins. All decoupling
capacitors should be located as close as possible to the package
pins. Placing series resistors close to the digital output pins
(Pins 1–12, 47–48) may help reduce digital code transition
noise. If the digital outputs must drive a load larger than 20 pF,
buffering is recommended to minimize additional noise.
The AD9848/AD9849 recommended circuit configuration for
External Mode is shown in Figure 21. All signals should be
carefully routed on the PCB to maintain low noise performance.
The CCD output signal should be connected to Pin 29 through
a 0.1 µF capacitor. The CCD timing signals H1–H4 and RG
should be routed directly to the CCD with minimum trace
lengths, as shown in Figures 22a and 22b. The digital outputs
and clock inputs are located on Pins 1–12 and Pins 36–48,
and should be connected to the digital ASIC, away from the
analog and CCD clock signals. The CLI signal from the ASIC
may be routed under the package to Pin 23. This will help separate
the CLI signal from the H1–H4 and RG signal routing.
Power supply decoupling is very important in achieving low
noise performance. Figure 21 shows the local high frequency
decoupling capacitors, but additional capacitance is recommended for lower frequencies. Additional capacitors and ferrite
beads can further reduce noise.
0.1F
3V
DIGITAL
SUPPLY
6
SDI
SCK
CLPOB
CLPDM
PBLK
HBLK
VD
HD
DVSS4
DVDD4
D0 (LSB)
D1
3
CLOCK
INPUTS
SERIAL
INTERFACE
1F
48 47 46 45 44 43 42 41 40 39 38 37
D2 1
D3
D4
D5
3V
DRIVER
SUPPLY
0.1F
D6
DVSS3
DVDD3
D7
D8
36
PIN 1
IDENTIFIER
2
35
3
34
4
33
5
32
6
AD984 9
7
TOP VIEW
(Not to Scale)
8
31
30
29
9
28
D9 10
27
D10 11
(MSB) D11
26
12
25
1F
REFB
0.1F
CMLEVEL
0.1F
AVSS3
3V
ANALOG
SUPPLY
AVDD3
BYP3
CCDIN
BYP2
0.1F
BYP1
3V
ANALOG
SUPPLY
AVDD2
AVSS2
0.1F
12
0.1F 0.1F 0.1F
AVDD1
CLI
AVSS1
DVDD2
RG
DVSS2
H4
H3
DVDD1
DVSS1
H DRIVER
SUPPLY
H2
13 14 15 16 17 18 19 20 21 22 23 24
H1
DATA
OUTPUTS
SL
REFT
CLOCK
INPUT
3V
ANALOG
SUPPLY
RG DRIVER
SUPPLY
0.1F
0.1F
0.1F
5
HIGH-SPEED
CLOCKS
Figure 21. Recommend Circuit Configuration for External Mode
REV. 0
–31–
CCD
SIGNAL
AD9848/AD9849
Driving the CLI Input
The AD9848/AD9849’s master clock input (CLI) may be
used in two different configurations, depending on the application. Figure 23a shows a typical dc-coupled input from the
master clock source. When the dc-coupled technique is used,
the master clock signal should be at standard 3 V CMOS
logic levels. As shown in Figure 23b, a 1000 pF ac-coupling
capacitor may be used between the clock source and the CLI
input. In this configuration, the CLI input will self-bias to
the proper dc voltage level of approximately 1.4 V. When the
ac-coupled technique is used, the master clock signal can be
as low as ± 500 mV in amplitude.
AD9848/AD9849
23
ASIC
CLI
MASTER CLOCK
Figure 23a. CLI Connection, DC-Coupled
CCDIN
29
AD9848/AD9849
AD9848/AD9849
17
18
H3
H4
13
H1
14
20
H2
RG
23
ASIC
CLI
LPF
1nF
SIGNAL
OUT
MASTER CLOCK
H1
H2
RG
Figure 23b. CLI Connection, AC-Coupled
CCD IMAGER
Internal Mode Circuit Configuration
Figure 22a. CCD Connections (2 H-Clock)
CCDIN
29
AD9848/AD9849
18
20
2
VD
SIGNAL
OUT
44 43
H1
H2
42
41
HD/VD
INPUTS
CLPOB
RG
HBLK
H4
CLPDM
17
H3
PBLK
14
H2
HD
13
H1
The AD9848/AD9849 may be used in Internal Mode using
the circuit configuration of Figure 24. Internal Mode uses the
same circuit as Figure 21, except that the horizontal pulses
(CLPOB, CLPDM, PBLK, and HBLK) are internally generated in the AD9848/AD9849. These pins may be grounded when
Internal Mode is used. Only the HD and VD signals are required
from the ASIC.
40
39
RG
CCD IMAGER
H2
AD9848/AD9849
H1
Figure 24. Internal Mode Circuit Configuration
Figure 22b. CCD Connections (4 H-Clock)
–32–
REV. 0
AD9848/AD9849
TIMING EXAMPLES FOR DIFFERENT SEQUENCES
2
SEQUENCE 2
V
SEQUENCE 3
10
4
H
SEQUENCE 2
48
28
Figure 25.
CCDIN
INVALID PIXELS
VERT SHIFT DUMMY
INVALID PIXELS
VERT SHIFT
SHP
SHD
H1/H3
H2/H4
HBLK
PBLK
CLPOB
CLPDM
Figure 26. Sequence 1: Vertical Blanking
EFF. PIXELS
CCDIN
OPTICAL BLACK VERT SHIFT DUMMY
OPTICAL BLACK
SHP
SHD
H1/H3
H2/H4
HBLK
PBLK
CLPOB
CLPDM
Figure 27. Sequence 2: Vertical Optical Black
REV. 0
–33–
VERT SHIFT
AD9848/AD9849
EFF. PIXELS
CCDIN
OPTICAL BLACK VERT SHIFT DUMMY OB
EFFECTIVE PIXELS
OPTICAL BLACK VERT SHIFT
SHP
SHD
H1/H3
H2/H4
HBLK
PBLK
CLPOB
CLPDM
Figure 28. Sequence 3: Effective Pixels
–34–
REV. 0
AD9848/AD9849
OUTLINE DIMENSIONS
Dimensions shown in inches and (mm).
48-Lead LQFP
(ST-48)
0.063 (1.60)
MAX
0.354 (9.00) BSC SQ
0.030 (0.75)
0.018 (0.45)
37
48
36
1
0.276
(7.00)
BSC
SQ
TOP VIEW
(PINS DOWN)
COPLANARITY
0.003 (0.08)
0ⴗ
MIN
12
25
13
0.019 (0.5)
BSC
0.008 (0.2)
0.004 (0.09)
24
0.011 (0.27)
0.006 (0.17)
0.057 (1.45)
0.053 (1.35)
7ⴗ
0ⴗ
0.006 (0.15) SEATING
0.002 (0.05) PLANE
REV. 0
–35–
–36–
PRINTED IN U.S.A.
C02498–1–7/01(0)