AD9945 [ADI]
Complete 12-Bit 40 MHz CCD Signal Processor; 完整的12位40 MHz的CCD信号处理器
| 型号： | AD9945 |
| 厂家： | 
ADI |
| 描述： | Complete 12-Bit 40 MHz CCD Signal Processor |
| 文件： | 总16页 (文件大小：191K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
Complete 12-Bit 40 MHz
CCD Signal Processor
AD9945
FEATURES
GENERAL DESCRIPTION
40 MSPS Correlated Double Sampler (CDS)
6 dB to 40 dB 10-Bit Variable Gain Amplifier (VGA)
Low Noise Optical Black Clamp Circuit
Preblanking Function
12-Bit 40 MSPS A/D Converter
No Missing Codes Guaranteed
3-Wire Serial Digital Interface
3 V Single-Supply Operation
The AD9945 is a complete analog signal processor for CCD
applications. It features a 40 MHz single-channel architecture
designed to sample and condition the outputs of interlaced and
progressive scan area CCD arrays. The AD9945’s signal chain
consists of a correlated double sampler (CDS), a digitally con-
trolled variable gain amplifier (VGA), a black level clamp, and a
12-bit A/D converter.
The internal registers are programmed through a 3-wire serial digital
interface. Programmable features include gain adjustment, black
level adjustment, input clock polarity, and power-down modes.
Low Power: 140 mW @ 3 V Supply
Space-Saving 32-Lead 5 mm
ꢀ 5 mm LFCSP
APPLICATIONS
The AD9945 operates from a single 3 V power supply, typi-
cally dissipates 140 mW, and is packaged in a space-saving
32-lead LFCSP.
Digital Still Cameras
Digital Video Camcorders
PC Cameras
Portable CCD Imaging Devices
CCTV Cameras
FUNCTIONAL BLOCK DIAGRAM
REFT REFB
PBLK
AD9945
DRVDD
DRVSS
BAND GAP
REFERENCE
6dB TO 40dB
VGA
12
12-BIT
ADC
DOUT
CDS
CCDIN
CLP
10
AVDD
AVSS
CLPOB
CONTROL
REGISTERS
DVDD
DVSS
DIGITAL
INTERFACE
INTERNAL
TIMING
SHP
SHD DATACLK
SL
SCK
SDATA
REV. A
Information furnished by Analog Devices is believed to be accurate and
reliable. However, no responsibility is assumed by Analog Devices for its
use, norforanyinfringementsofpatentsorotherrightsofthirdpartiesthat
may result from its use. No license is granted by implication or otherwise
under any patent or patent rights of Analog Devices. Trademarks and
registered trademarks are the property of their respective owners.
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: 781/329-4700
Fax: 781/326-8703
www.analog.com
© 2003 Analog Devices, Inc. All rights reserved.
AD9945–SPECIFICATIONS
(TMIN to TMAX, AVDD = DVDD = DRVDD= 3.0 V, fSAMP = 40 MHz, unless otherwise noted.)
GENERAL SPECIFICATIONS
Parameter
Min
Typ
Max
Unit
TEMPERATURE RANGE
Operating
Storage
–20
–65
+85
+150
°C
°C
POWER SUPPLY VOLTAGE
Analog, Digital, Digital Driver
2.7
3.6
V
POWER CONSUMPTION
Normal Operation (DRVDD Power not Included)
DRVDD Power Only (CLOAD = 20 pF)
Power-Down Mode
140
10
1.5
mW
mW
mW
MAXIMUM CLOCK RATE
40
MHz
Specifications subject to change without notice.
DIGITAL SPECIFICATIONS(DRVDD = DVDD = 2.7 V, CL = 20 pF, unless otherwise noted.)
Parameter
Symbol
Min
Typ
Max
Unit
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
V
V
µA
µA
pF
0.6
10
10
10
LOGIC OUTPUTS
High Level Output Voltage, IOH = 2 mA
Low Level Output Voltage, IOL = 2 mA
VOH
VOL
2.2
V
V
0.5
Specifications subject to change without notice.
–2–
REV. A
AD9945
SYSTEM SPECIFICATIONS (TMIN to TMAX, AVDD = DVDD = DRVDD = 3.0 V, fSAMP = 40 MHz, unless otherwise noted.)
Parameter
Min
Typ Max
Unit
Notes
CDS
Maximum Input Range before Saturation*
Allowable CCD Reset Transient*
Maximum CCD Black Pixel Amplitude*
1.0
500
100
Vp-p
mV
mV
See Input Waveform in Footnote
VARIABLE GAIN AMPLIFIER (VGA)
Gain Control Resolution
Gain Monotonicity
1024
Guaranteed
Steps
Gain Range
Minimum Gain
Maximum Gain
5.3
41.5
dB
dB
See Figure 7 for VGA Gain Curve
See Variable Gain Amplifier Section for
VGA Gain Equation
40.0
BLACK LEVEL CLAMP
Clamp Level Resolution
Clamp Level
256
Steps
Measured at ADC Output
Minimum Clamp Level
Maximum Clamp Level
0
255
LSB
LSB
A/D CONVERTER
Resolution
12
Bits
Differential Nonlinearity (DNL)
No Missing Codes
0.5
Guaranteed
LSB
Data Output Coding
Full-Scale Input Voltage
Straight Binary
2.0
V
VOLTAGE REFERENCE
Reference Top Voltage (REFT)
Reference Bottom Voltage (REFB)
2.0
1.0
V
V
SYSTEM PERFORMANCE
Gain Range
Low Gain (VGA Code = 0)
Maximum Gain (VGA Code = 1023)
Gain Accuracy
Specifications Include Entire Signal Chain
12 dB Gain Applied
5.3
dB
dB
dB
%
40.0
41.5
ꢁ1.0
0.1
Peak Nonlinearity, 500 mV Input Signal
Total Output Noise
1.2
LSB rms AC Grounded Input, 6 dB Gain Applied
Power Supply Rejection (PSR)
40
dB
*Input Signal Characteristics defined as follows:
500mV TYP
RESET TRANSIENT
100mV TYP
1V TYP
OPTICAL BLACK PIXEL
INPUT SIGNAL RANGE
Specifications subject to change without notice.
REV. A
–3–
AD9945
TIMING SPECIFICATIONS
(CL = 20 pF, fSAMP = 40 MHz, CCD Mode Timing in Figures 8 and 9, Serial Timing in Figures 4 and 5.)
Parameter
Symbol
Min
Typ
Max
Unit
SAMPLE CLOCKS
DATACLK, SHP, SHD Clock Period
DATACLK High/Low Pulse Width
SHP Pulse Width
SHD Pulse Width
CLPOB Pulse Width*
SHP Rising Edge to SHD Falling Edge
SHP Rising Edge to SHD Rising Edge
Internal Clock Delay
tCONV
tADC
tSHP
tSHD
tCOB
tS1
25
10
ns
ns
ns
ns
Pixels
ns
ns
12.5
6.25
6.25
20
6.25
12.5
3
2
tS2
tID
11.25
ns
DATA OUTPUTS
Output Delay
Pipeline Delay
tOD
9.5
10
ns
Cycles
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
fSCLK
tLS
tLH
tDS
tDH
10
10
10
10
10
MHz
ns
ns
ns
ns
*Minimum CLPOB pulse width is for functional operation only. Wider typical pulses are recommended to achieve low noise clamp performance.
Specifications subject to change without notice.
ORDERING GUIDE
ABSOLUTE MAXIMUM RATINGS*
With
Respect
To
Temperature
Range
Package
Package
Model
Description1 Option
Parameter
Min Max
Unit
AD9945KCP
–20°C to +85°C LFCSP
–20°C to +85°C LFCSP
–20°C to +85°C LFCSP
–20°C to +85°C LFCSP
CP-32
CP-32
CP-32
CP-32
CP-32
AVDD
DVDD
DRVDD
AVSS
DVSS
DRVSS –0.3 +3.9
–0.3 +3.9
–0.3 +3.9
V
V
V
V
V
V
V
V
AD9945KCPRL
AD9945KCPRL7
AD9945KCPZ2
AD9945KCPZRL72 –20°C to +85°C LFCSP
Digital Outputs
SHP, SHD, DATACLK
CLPOB, PBLK
SCK, SL, SDATA
REFT, REFB, CCDIN
Junction Temperature
Lead Temperature
(10 sec)
DRVSS –0.3 DRVDD + 0.3
DVSS
DVSS
DVSS
AVSS
–0.3 DVDD + 0.3
–0.3 DVDD + 0.3
–0.3 DVDD + 0.3
–0.3 AVDD + 0.3
150
1LFCSP = Lead Frame Chip Scale Package
2Z = Pb-free part.
THERMAL CHARACTERISTICS
Thermal Resistance
32-Lead LFCSP Package
°C
°C
300
θ
JA = 27.7 °C/W
*Stresses above those listed under Absolute Maximum Ratings may cause perma-
nent damage to the device. This is a stress rating only; functional operation of the
device at these or any other conditions outside of those indicated in the operational
sections of this specification is not implied. Exposure to absolute maximum ratings
for extended periods may affect device reliability.
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
AD9945 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.
–4–
REV. A
AD9945
PIN CONFIGURATION
D2
D3
D4
D5
D6
D7
D8
D9
1
2
3
4
5
6
7
8
24 REFB
PIN 1
INDICATOR
23 REFT
22 CCDIN
21 AVSS
20 AVDD
19 SHD
AD9945
TOP VIEW
18 SHP
17 CLPOB
PIN FUNCTION DESCRIPTIONS
Pin Number
Mnemonic
Type
Description
1 to 10, 31, 32
11
12
13
14
15
D2 to D11, D0, D1
DRVDD
DRVSS
DVDD
DATACLK
DVSS
DO
P
P
P
DI
P
Digital Data Outputs
Digital Output Driver Supply
Digital Output Driver Ground
Digital Supply
Digital Data Output Latch Clock
Digital Supply Ground
16
17
18
19
20
21
PBLK
CLPOB
SHP
SHD
AVDD
AVSS
DI
DI
DI
DI
P
Preblanking Clock Input
Black Level Clamp Clock Input
CDS Sampling Clock for CCD’s Reference Level
CDS Sampling Clock for CCD’s Data Level
Analog Supply
P
Analog Ground
22
23
24
25
26
27
28 to 30
CCDIN
REFT
REFB
SL
SDATA
SCK
AI
AO
AO
DI
DI
DI
NC
Analog Input for CCD Signal
A/D Converter Top Reference Voltage Decoupling
A/D Converter Bottom Reference Voltage Decoupling
Serial Digital Interface Load Pulse
Serial Digital Interface Data Input
Serial Digital Interface Clock Input
Internally Pulled Down. Float or connect to GND.
NC
TYPE: AI = Analog Input, AO = Analog Output, DI = Digital Input, DO = Digital Output, P = Power.
REV. A
–5–
AD9945
DEFINITIONS OF SPECIFICATIONS
Differential Nonlinearity (DNL)
at the specified gain setting. The output noise can be converted
to an equivalent voltage, using the relationship
An ideal ADC exhibits code transitions that are exactly 1 LSB
apart. DNL is the deviation from this ideal value. Thus, every
code must have a finite width. No missing codes guaranteed to
12-bit resolution indicates that all 4096 codes must be present
over all operating conditions.
1 LSB = (ADC Full Scale/2N codes)
where N is the bit resolution of the ADC. For the AD9945,
1 LSB is 0.5 mV.
Power Supply Rejection (PSR)
The PSR is measured with a step change applied to the supply
pins. This represents a very high frequency disturbance on the
AD9945’s power supply. The PSR specification is calculated
from the change in the data outputs for a given step change in
the supply voltage.
Peak Nonlinearity
Peak nonlinearity, a full signal chain specification, refers to the
peak deviation of the output of the AD9945 from a true straight
line. The point used as zero scale occurs 1/2 LSB before the first
code transition. Positive full scale is defined as a level 1 1/2 LSB
beyond the last code transition. The deviation is measured from
the middle of each particular output code to the true straight line.
The error is then expressed as a percentage of the 2 V ADC full-
scale signal. The input signal is always appropriately gained up to
fill the ADC’s full-scale range.
Internal Delay for SHP/SHD
The internal delay (also called aperture delay) is the delay that
occurs from the time when a sampling edge is applied to the
AD9945 until the actual sample of the input signal is held. Both
SHP and SHD sample the input signal during the transition from
low to high, so the internal delay is measured from each clock’s
rising edge to the instant the actual internal sample is taken.
Total Output Noise
The rms output noise is measured using histogram techniques.
The standard deviation of the ADC output codes is calculated in
LSB and represents the rms noise level of the total signal chain
EQUIVALENT INPUT CIRCUITS
DVDD
AVDD
330ꢂ
60ꢂ
AVSS
AVSS
DVSS
Figure 3. CCDIN (Pin 22)
Figure 1. Digital Inputs—SHP, SHD,
DATACLK, CLPOB, PBLK, SCK, SL, SDATA
DRVDD
DVDD
DATA
THREE-
STATE
DOUT
DVSS
DRVSS
Figure 2. Data Outputs—D0 to D11
–6–
REV. A
Typical Performance Characteristics–AD9945
1.0
180
165
150
135
0.5
0
V
V
V
= 3.3 V
= 3.0 V
= 2.7 V
DD
DD
DD
120
–0.5
105
90
–1.0
25
32
40
0
800
1600
2400
3200
4000
SAMPLE RATE (MHz)
CODE
TPC 1. Power vs. Sampling Rate
TPC 2. Typical DNL Performance
REV. A
–7–
AD9945
INTERNAL REGISTER DESCRIPTION
Table I. Internal Register Map
Function
Register
Name
Address Bits
A2 A1 A0
Data Bits
Operation
0
0
0
D0
D2, D1
D3
D5, D4
D6
D8, D7
D11 to D9
Software Reset (0 = Normal Operation, 1 = Reset all registers to default)
Power-Down Modes (00 = Normal Power, 01 = Standby, 10 = Total Shutdown)
OB Clamp Disable (0 = Clamp ON, 1 = Clamp OFF)
Test Mode. Should always be set to 00.
PBLK Blanking Level (0 = Blank Output to Zero, 1 = Blank to OB Clamp Level)
Test Mode 1. Should always be set to 00.
Test Mode 2. Should always be set to 000.
Control
0
0
1
D0
D1
D2
D3
SHP/SHD Input Polarity (0 = Active Low, 1 = Active High)
DATACLK Input Polarity (0 = Active Low, 1 = Active High)
CLPOB Input Polarity (0 = Active Low, 1 = Active High)
PBLK Input Polarity (0 = Active Low, 1 = Active High)
D4
D5
D6
D11 to D7
Three-State Data Outputs (0 = Outputs Active, 1 = Outputs Three-Stated)
Data Output Latching (0 = Latched by DATACLK, 1 = Latch is Transparent)
Data Output Coding (0 = Binary Output, 1 = Gray Code Output)
Test Mode. Should always be set to 00000.
Clamp Level
VGA Gain
0
0
1
1
0
1
D7 to D0
D9 to D0
OB Clamp Level (0 = 0 LSB, 255 = 255 LSB)
VGA Gain (0 = 6 dB, 1023 = 40 dB)
NOTE: All register values default to 0x000 at power-up except clamp level, which defaults to 128 decimal (128 LSB clamp level).
–8–
REV. A
AD9945
SERIAL INTERFACE
TEST BIT
0
SDATA
tDS
A0
A1
A2
D0
D1
D2
D3
D4
D5
D6
D7
D8
D9
D10
D11
tDH
SCK
tLS
tLH
SL
NOTES
1. SDATA BITS ARE INTERNALLY LATCHED ON THE RISING EDGES OF SCK.
2. SYSTEM UPDATE OF LOADED REGISTERS OCCURS ON SL RISING EDGE.
3. ALL 12 DATA BITS D0 TO D11 MUST BE WRITTEN. IF THE REGISTER CONTAINS FEWER THAN 12 BITS, ZEROS SHOULD BE
USED FOR THE UNDEFINED BITS.
4. TEST BIT IS FOR INTERNAL USE ONLY. MUST BE SET LOW.
Figure 4. Serial Write Operation
DATA FOR STARTING
REGISTER ADDRESS
DATA FOR NEXT
REGISTER ADDRESS
TEST
BIT
...
SDATA
A0
A1
A2
D0
D1
D2
D3
D4
D5
D10 D11 D0
D1
0
D2
31 ...
...
SCK
SL
30
17
18
27
28
29
15
16
1
2
3
4
5
6
7
8
9
10
NOTES
1. MULTIPLE SEQUENTIAL REGISTERS MAY BE LOADED CONTINUOUSLY.
2. THE FIRST (LOWEST ADDRESS) REGISTER ADDRESS IS WRITTEN, FOLLOWED BY MULTIPLE 12-BIT DATA-WORDS.
3. THE ADDRESS WILL AUTOMATICALLY INCREMENT WITH EACH 12-BIT DATA-WORD (ALL 12 BITS MUST BE WRITTEN).
4. SL IS HELD LOW UNTIL THE LAST DESIRED REGISTER HAS BEEN LOADED.
5. NEW DATA IS UPDATED AT THE NEXT SL RISING EDGE.
Figure 5. Continuous Serial Write Operation to All Registers
REV. A
–9–
AD9945
DC RESTORE
CDS
INTERNAL
V
REF
6dB TO 40dB
VGA
2V FULL SCALE
0.1ꢃF
CCDIN
12
12-BIT
ADC
DOUT
CLPOB
OPTICAL BLACK
CLAMP
8-BIT
DAC
10
DIGITAL
FILTERING
VGA GAIN
REGISTER
8
CLAMP LEVEL
REGISTER
Figure 6. CCD Mode Block Diagram
CIRCUIT DESCRIPTION AND OPERATION
The AD9945 signal processing chain is shown in Figure 6. Each
processing step is essential in achieving a high quality image from
the raw CCD pixel data.
When the loop is disabled, the clamp level register may still be
used to provide programmable offset adjustment.
Horizontal timing is shown in Figure 9. The CLPOB pulse should
be placed during the CCD’s optical black pixels. It is recom-
mended that the CLPOB pulse be used during valid CCD dark
pixels. The CLPOB pulse should be a minimum of 20 pixels wide
to minimize clamp noise. Shorter pulse widths may be used, but
clamp noise may increase and the loop’s ability to track low fre-
quency variations in the black level will be reduced.
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 single supply
of the AD9945.
A/D Converter
Correlated Double Sampler
The ADC uses a 2 V input range. Better noise performance results
from using a larger ADC full-scale range. The ADC uses a
pipelined architecture with a 2 V full-scale input for low noise
performance.
The CDS circuit samples each CCD pixel twice to extract the
video information and reject low frequency noise. The timing
shown in Figure 8 illustrates how the two CDS clocks, SHP and
SHD, are used to sample the reference level and data level of
the CCD signal, respectively. The CCD signal is sampled on the
rising edges of SHP and SHD. Placement of these two clock
signals is critical in achieving the best performance from the CCD.
An internal SHP/SHD delay (tID) of 3 ns is caused by internal
propagation delays.
Variable Gain Amplifier
The VGA stage provides a gain range of 6 dB to 40 dB, program-
mable with 10-bit resolution through the serial digital interface.
The minimum gain of 6 dB is needed to match a 1 V input signal
with the ADC full-scale range of 2 V. A plot of the VGA gain curve
is shown in Figure 7.
Optical Black Clamp
VGAGain dB = VGACode × 0.035 dB + 5.3 dB
(
)
(
)
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 the
fixed black level reference, selected by the user in the clamp
level register. 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 postprocessing, the AD9945
optical black clamping may be disabled using Bit D3 in the
operation register (see the Serial Interface Timing and Internal
Register Description sections).
42
36
30
24
18
12
6
0
127
255
383
511
639
767
895
1023
VGA GAIN REGISTER CODE
Figure 7. VGA Gain Curve
–10–
REV. A
AD9945
CCD MODE TIMING
CCD
SIGNAL
tID
N
N+1
N+2
N+9
N+10
tID
SHP
tS1
tS2
tCP
SHD
DATACLK
tOD
OUTPUT
DATA
N–10
N–9
N–8
N–1
N
NOTES
1. RECOMMENDED PLACEMENT FOR DATACLK RISING EDGE IS BETWEEN THE SHD RISING EDGE AND NEXT SHP FALLING EDGE.
2. CCD SIGNAL IS SAMPLED AT SHP AND SHD RISING EDGES.
Figure 8. CCD Mode Timing
HORIZONTAL
BLANKING
EFFECTIVE PIXELS
OPTICAL BLACK PIXELS
DUMMY PIXELS
EFFECTIVE PIXELS
CCD
SIGNAL
CLPOB
PBLK
OUTPUT
DATA
EFFECTIVE PIXEL DATA
OB PIXEL DATA
DUMMY BLACK
EFFECTIVE DATA
NOTES
1. CLPOB WILL OVERWRITE PBLK. PBLK WILL NOT AFFECT CLAMP OPERATION IF OVERLAPPING WITH CLPOB.
2. PBLK SIGNAL IS OPTIONAL.
3. DIGITAL OUTPUT DATA WILL BE ALL ZEROS DURING PBLK. OUTPUT DATA LATENCY IS NINE DATACLK CYCLES.
Figure 9. Typical CCD Mode Line Clamp Timing
REV. A
–11–
AD9945
APPLICATIONS INFORMATION
level correction, and analog-to-digital conversion. The AD9945’s
digital output data is then processed by the image processing
ASIC. The internal registers of the AD9945—used to control
gain, offset level, and other functions—are programmed by the
ASIC or microprocessor through a 3-wire serial digital interface.
A system timing generator provides the clock signals for both the
CCD and the AFE.
The AD9945 is a complete analog front end (AFE) product for
digital still camera and camcorder applications. As shown in
Figure 10, the CCD image (pixel) data is buffered and sent to the
AD9945 analog input through a series input capacitor. The
AD9945 performs the dc restoration, CDS, gain adjustment, black
DIGITAL
OUTPUTS
AD9945
CCD
V
OUT
ADC
OUT
0.1ꢃF
DIGITAL IMAGE
PROCESSING
ASIC
CCDIN
SERIAL
INTERFACE
REGISTER-
DATA
BUFFER
CDS/CLAMP
TIMING
V-DRIVE
CCD
TIMING
TIMING
GENERATOR
Figure 10. System Applications Diagram
–12–
REV. A
AD9945
Internal Power-On Reset Circuitry
and bypass pins and their respective ground pins. All decoupling
capacitors should be located as close as possible to the package
pins. A single clean power supply is recommended for the AD9945,
but a separate digital driver supply may be used for DRVDD
(Pin 11). DRVDD should always be decoupled to DRVSS (Pin 12),
which should be connected to the analog ground plane. Advan-
tages of using a separate digital driver supply include using a
lower voltage (2.7 V) to match levels with a 2.7 V ASIC, reducing
digital power dissipation, and reducing potential noise coupling.
If the digital outputs (Pins 1 to 10, 31, and 32) must drive a
load larger than 20 pF, buffering is recommended to reduce
digital code transition noise. Alternatively, placing series resis-
tors close to the digital output pins may also help reduce noise.
After power-on, the AD9945 will automatically reset all internal
registers and perform internal calibration procedures. This takes
approximately 1 ms to complete. During this time, normal clock
signals and serial write operations may occur. However, serial
register writes will be ignored until the internal reset operation
is completed.
Grounding and Decoupling Recommendations
As shown in Figure 11, a single ground plane is recommended for
the AD9945. This ground plane should be as continuous as
possible. This will ensure that all analog decoupling capacitors
provide the lowest possible impedance path between the power
3
SERIAL
INTERFACE
D0
D1
24 REFB
23 REFT
22 CCDIN
1.0ꢃF
1.0ꢃF
D2
D3
D4
1
2
3
PIN 1
IDENTIFIER
0.1ꢃF
CCDIN
21 AVSS
20 AVDD
D5
D6
D7
D8
4
5
6
7
AD9945
3V
ANALOG
SUPPLY
19 SHD
0.1ꢃF
TOP VIEW
(Not to Scale)
18 SHP
D9
8
17 CLPOB
12
5
CLOCK
INPUTS
DATA
OUTPUTS
3V
DRIVER
SUPPLY
3V
ANALOG
SUPPLY
0.1ꢃF
0.1ꢃF
NC = NO CONNECT
NOTE
THE EXPOSED PAD ON THE BOTTOM OF THE AD9945 SHOULD BE
SOLDERED TO THE GND PLANE OF THE PRINTED CIRCUIT BOARD
Figure 11. Recommended Circuit Configuration for CCD Mode
REV. A
–13–
AD9945
OUTLINE DIMENSIONS
32-Lead Lead Frame Chip Scale Package (LFCSP)
5 mm ꢀ 5 mm Body
(CP-32)
Dimensions shown in millimeters
5.00
BSC SQ
0.60 MAX
PIN 1
0.60 MAX
INDICATOR
25
24
32
1
PIN 1
INDICATOR
0.50
BSC
3.25
3.10
2.95
4.75
BSC SQ
TOP
VIEW
BOTTOM
VIEW
SQ
0.50
0.40
0.30
17
16
8
9
3.50
REF
0.80 MAX
0.65 NOM
12ꢄ MAX
0.05 MAX
0.02 NOM
1.00
0.90
0.80
0.30
0.23
0.18
COPLANARITY
0.08
0.20 REF
SEATING
PLANE
COMPLIANT TO JEDEC STANDARDS MO-220-VHHD-2
–14–
REV. A
AD9945
Revision History
Location
Page
11/03—Data Sheet changed from REV. 0 to REV. A
Changes to TIMING SPECIFICATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Changes to ORDERING GUIDE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Changes to Figure 11 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Updated OUTLINE DIMENSIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
REV. A
–15–
–16–
相关型号：
AD9945KCPZRL
IC SPECIALTY CONSUMER CIRCUIT, QCC32, 5 X 5 MM, MO-220-VHHD-2, LFCSP-32, Consumer IC:Other
ADI
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