FEATURES
12 MSPS Correlated Double Sampler (CDS)
10-Bit 12 MHz A/D Converter
No Missing Codes Guaranteed
6 dB to 40 dB Variable Gain Amplifier (VGA)
Black Level Clamp with Variable Level Control
Complete On-Chip Timing Generator
Precision Timing Core with 1.7 ns Resolution
On-Chip: 6-Channel Horizontal and 1-Channel RS Drivers
4-Phase Vertical Transfer Clocks
Electronic and Mechanical Shutter Modes
On-Chip Sync Generator with External Sync Option
APPLICATIONS
Digital Still Cameras
Industrial Imaging
FUNCTIONAL BLOCK DIAGRAM
RS
H1 A–D
H2 A, B
V1 A/B
V3 A/B
TG1A
TG1B
TG3A
TG3B
AD9937
6
V2
V4
4
4
CDS
HORIZONTAL
DRIVERS
V- H
CONTROL
6dB TO 40dB
VGA
INTERNAL CLOCKS
PRECISION
GENERATOR
GENERATOR
GENERAL DESCRIPTION
The AD9937 is a highly integrated CCD signal processor. It
includes a complete analog front end with A/D conversion,
combined with a full-function programmable timing generator.
A Precision Timing core allows adjustment of high speed clocks
with 1.7 ns resolution at 12 MHz operation.
The AD9937 is specified at pixel rates of up to 12 MHz. The
analog front end includes black level clamping, CDS, VGA, and
a 10-bit A/D converter. The timing generator provides all the
necessary CCD clocks: RS, H-clocks, V-clocks, sensor gate pulses,
and substrate charge reset pulse. Operation is programmed using a
3-wire serial interface.
The AD9937 is packaged in a 56-lead LFCSP and specified over
an operating temperature range of –25°C to +85°C.
REFT REFB
VREF
ADC
CLAMP
TIMING
SYNC
INTERNAL
REGISTERS
10
DOUT
VCLK
LMOFDHD VD
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. Trademarks and
registered trademarks are the property of their respective companies.
Reference Top Voltage (REFT)2.0V
Reference Bottom Voltage (REFB)1.0V
SYSTEM PERFORMANCEIncludes entire signal chain.
Gain Accuracy
Low Gain (VGA Code 17)567dBGain = (0.035 × Code) + 5.4 dB
Max Gain (VGA Code 1023)40.241.242.2dB
Peak Nonlinearity, 500 mV Input Signal0.1%12 dB gain applied.
Total Output Noise0.3LSB rmsAC ground input, 6 dB gain applied.
Power Supply Rejection (PSR)40dBMeasured with step change on supply.
*Input signal characteristics defined as follows:
500mV TYP
RESET
TRANSIENT
100mV MAX
OPTICAL
BLACK PI XEL
Specifications subject to change without notice.
1V MAX
INPUT
SIGNAL RANGE
REV. 0–4–
Page 5
AD9937
TIMING SPECIFICATIONS
(CL = 20 pF, AVDD = DVDD = DRVDD = 3 V, f
= 12 MHz, unless otherwise noted.)
CLI
ParameterSymbolMinTypMaxUnit
MASTER CLOCK, VCKM
VCKM Clock Periodt
CONV
83.33ns
VCKM High/Low Pulsewidth41.67ns
Delay from VCKM Rising Edge to Internal Pixel Position 0t
AFE CLAMP PULSES
CLPOB Pulsewidth
AFE SAMPLE LOCATION
1
2
1
(See Figure 13)
SHP Sample Edge to SHD Sample Edget
VCKMDLY
S1
220Pixels
33.3441.67ns
9ns
DATA OUTPUTS
Output Delay from VCLK Rising Edget
OD
9ns
Pipeline Delay from SHP/SHD Sampling (See Figure 40)9Cycles
SERIAL INTERFACE
Maximum SCK Frequencyf
SLD to SCK Setup Timet
SCK to SLD Hold Timet
SDA Valid to SCK Rising Edge Setupt
SCK Falling Edge to SDA Valid Holdt
SCK Falling Edge to SDA Valid Readt
NOTES
1
Parameter is programmable.
2
Minimum CLPOB pulsewidth is for functional operation only. Wider typical pulses are recommended to achieve good clamp performance.
RS OutputRSVSS–0.3 RSVDD + 0.3 V
H1(A–D), H2(A, B)Output HVSS–0.3 HVDD + 0.3 V
Digital OutputsDVSS–0.3DVDD + 0.3 V
Digital InputsDVSS–0.3 DVDD + 0.3 V
AD9937KCPRL–25°C to +85°CLead FrameCP-56
SCK, SLD, SDADVSS–0.3DVDD + 0.3 V
VRT, VRBAVSS–0.3AVDD + 0.3 V
CCDINAVSS–0.3AVDD + 0.3 V
Junction Temperature150°C
Lead Temperature, 10 sec350°C
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
AD9937 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.
31NCNCNo Connect
32TCVSSPAnalog Ground for Timing Core
33TCVDDPAnalog Supply for Timing Core
34VCKMDI
3
Reference Clock Input
35AVDDPAnalog Supply for AFE
36CCDINAICCD Input Signal
37AVSSPAnalog Ground for AFE
38REFTAOVoltage Reference Top Bypass
39REFBAOVoltage Reference Bottom Bypass
40TG1ADOCCD Sensor Gate Pulse 1
41V1A/BDOCCD Vertical Transfer Clock 1
42TG1BDOCCD Sensor Gate Pulse 2
43V2DOCCD Vertical Transfer Clock 2
44TG3ADOCCD Sensor Gate Pulse 3
45V3A/BDOCCD Vertical Transfer Clock 3
46TG3BDOCCD Sensor Gate Pulse 4
47V4DOCCD Vertical Transfer Clock 4
48LMDOLine Memory Control Pulse
49DVDDPDigital Supply
50DVSSPDigital Ground
51OFDDOCCD Substrate Reset Pulse
52HDDOHorizontal Sync Pulse
53VDDOVertical Sync Pulse
54SLDDI
55SDADI
56SCKDI
NOTES
1
See Figure 41 for circuit configuration.
2
AI = Analog Input, AO = Analog Output, DI = Digital Input,
DO = Digital Output, DIO = Digital Input/Output, P = Power,
NC = No Connection.
3
Schmitt trigger type input.
3
3-Wire Serial Load Pulse
3
3-Wire Serial Data
3
3-Wire Serial Clock
REV. 0–6–
Page 7
AD9937
TERMINOLOGY
Differential Nonlinearity (DNL)
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
10-bit resolution indicates that all 1024 codes must be present
over all operating conditions.
Peak Nonlinearity
Peak nonlinearity, a full signal chain specification, refers to the
peak deviation of the output of the AD9937 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 fullscale signal. The input signal is always appropriately gained up
to fill the ADC’s full-scale range.
EQUIVALENT CIRCUITS
AVDD
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 at the specified gain setting. The output noise can be
converted to an equivalent voltage, using the relationship
12LSBADC Full Scalecodes
=
()
N
where N is the bit resolution of the ADC. For the AD9937, 1 LSB
is 1.95 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
AD9937’s power supply. The PSR specification is calculated
from the change in the data outputs for a given step change in
the supply voltage.
DVDD
330
DATA
TRISTATEOUT
R
AVSS
AVSS
Figure 1. CCDIN
DVDD
DVSS
DRVDD
DRVSS
Figure 2. Digital Data Outputs
DOUT
DVSS
Figure 3. Digital Inputs
HVDD1, HVDD2,
OR RSVDD
RS,
H1 (A–D),
H2 (A, B)
ENABLE
HVSS1, HVSS2,
OR RSVSS
OUTPUT
Figure 4. H1(A–D), H2(A, B), and RS Drivers
REV. 0
–7–
Page 8
AD9937–Typical Performance Characteristics
0
160
150
140
130
120
POWER DISSIPATION – mW
110
100
81210
VDD = 3.3V
VDD = 3.0V
VDD = 2.7V
TPC 1. Power vs. Sample Rate
SAMPLE RATE – MHz
0.50
0.25
0
DNL – LSB
–0.25
–0.50
0200
VDD = 3.0V
400600800100
CODE
TPC 2. Typical DNL Performance
REV. 0–8–
Page 9
AD9937
Table I. Control Register Map
BitBitRegister
AddrBreakdown WidthDefaultNameFunction
0(23:0)240SW_RESETSoftware Reset = 000000 (Reset All Registers to Default).
1010 OUTCONT_REGInternal OUTCONT Signal Control (0 = Digital Outputs held
at fixed dc level, 1 = Normal Operation).
(23:1)23Unused
2(1:0)20AFE_STBYAFE Standby (0 = Full Standby, 1 = Normal Operation,
2/3 = Reference Standby).
210DIG_STBYDigital Standby (0 = Full Standby, 1 = Normal Operation).
(23:3)21Unused
3(7:0)80x80REFBLACKBlack Clamp Level.
811BC_EN1 = Black Clamp Enable.
910TESTMODEThis register should always be set to 0.
1010TESTMODEThis register should always be set to 0.
1110PBLK_LEVEL0 = Blank to 0, 1 = Blank to Clamp Level (REFBLACK).
1210TRISTATEOUT0 = Data Outputs are Driven, 1 = Data Outputs are Three-Stated.
1310 RETIMEOUT_BAR 0 = Retime Data Outputs, 1 = Do Not Retime Data Outputs.
1410GRAY_ENCODE1 = Gray Encode ADC Outputs.
(16:15)20TESTMODEThis register should always be set to 0.
1710TESTMODEThis register should always be set to 0.
1811TESTMODEThis register should always be set to 1.
(23:19)5Unused
110H1BLKRETIMERetimes the H1 HBLK to Internal Clock.
210LM_INVERTLM Inversion Control (1 = Invert Programmed LM).
310TGOFD_INVERTTG and OFD Inversion Control (1 = Invert Programmed TG
and ODF).
410VDHD_INVERTVD and HD Inversion Control (1 = Invert Programmed VD
and HD; Note that Internal VD/HD Are HI Active).
510MASTEROperating Mode (0 = Slave Mode, 1 = Master Mode).
(23:6)18Unused
(15:8)85LMTOG1_0LM Pattern 0 (LM0): Toggle Position 1
(23:16)855LMTOG2_0LM Pattern 0 (LM0): Toggle Position 2
(31:24)887SPHSTART0LM Pattern 0 (LM0): Special H Pulse Start Position
(15:8)82LMTOG1_1LM Pattern 1 (LM1): Toggle Position 1
(23:16)826LMTOG2_1LM Pattern 1 (LM1): Toggle Position 2
(31:24)80SPHSTART1LM Pattern 1 (LM1): Special H Pulse Start Position
REV. 0–12–
Page 13
Table IV. Shutter System Register Map (Addr 0x16)
BitBitRegister
AddrBreakdownWidthDefaultNameFunction
Shut_Reg(0)(11:0)12ENDADDRESSSub Word End Address
(23:12)12STARTADDRESS Sub Word Start Address
(31:24)8SHUT_Reg_Addr System Register Address 0x16
Shut_Reg(1)(11:0)1280TGTOG1_0TG0 Pulse Toggle Position 1
(23:12)12370TGTOG2_0TG0 Pulse Toggle Position 2
(31:24)8Unused
Shut_Reg(2)(11:0)12490TGTOG1_1TG1 Pulse Toggle Position 1
(23:12)12780TGTOG2_1TG1 Pulse Toggle Position 2
(31:24)8Unused
Shut_Reg(3)(11:0)12540OFDTOG1_0OFD0 Pulse Toggle Position 1
(23:12)12720OFDTOG2_0OFD0 Pulse Toggle Position 2
(31:24)8Unused
Shut_Reg(4)(11:0)12830OFDTOG1_1OFD1 Pulse Toggle Position 1
(23:12)12860OFDTOG2_1OFD1 Pulse Toggle Position 2
(31:24)8Unused
AD9937
REV. 0
–13–
Page 14
AD9937
Table V. Mode_A (Addr 0x17)
BitBitRegister
AddrBreakdownWidthDefaultNameFunction
Mode_Reg(0)(11:0)12ENDADDRESSSub Word End Address
(23:12)12STARTADDRESSSub Word Start Address
(31:24)8MODE_Reg_AddrMode Register Address (Mode A = Addr 0x17)
(23:12)12866HDTOG2HD Toggle Position 2
(31:24)8Unused
Mode_Reg(3)(11:0)124095HDTOG3HD Toggle Position 3
(23:12)124095HDTOG4HD Toggle Position 4
(31:24)8Unused
Mode_Reg(4)(11:0)122339HDLASTLENHD Last Line Length
(22:12)11262VDLENVD Field Length
(26:23)40VDTOG1VD Toggle Position 1
(30:27)44VDTOG2VD Toggle Position 2
311Unused
Mode_Reg(5)(11:0)121543CLPOBTOG1CLPOB Toggle Position 1
(23:12)121557CLPOBTOG2CLPOB Toggle Position 2
(31:24)8Unused
Mode_Reg(6)(11:0)124095CLPOBTOG3CLPOB Toggle Position 3
(23:12)124095CLPOBTOG4CLPOB Toggle Position 4
(31:24)8Unused
Mode_Reg(7)(11:0)120HBLKTOG1HBLK Toggle Position 1
(23:12)12869HBLKTOG2HBLK Toggle Position 2
2410H1TOG12POLH1 Polarity between Toggle Positions 1 and 2
(31:25)7Unused
Mode_Reg(8)(11:0)124095HBLKTOG3HBLK Toggle Position 3
(23:12)124095HBLKTOG4HBLK Toggle Position 4
2410H1TOG34POLH1 Polarity between Toggle Positions 3 and 4
(31:25)7Unused
Mode_Reg(9)(11:0)126PBLKTOG1PBLK Toggle Position 1
(23:12)12878PBLKTOG2PBLK Toggle Position 2
(31:24)8Unused
Mode_Reg(10) (11:0)124095PBLKTOG3PBLK Toggle Position 3
(23:12)124095PBLKTOG4PBLK Toggle Position 4
(31:24)8Unused
Mode_Reg(11) (10:0)11255PBLKSTARTPBLK Start Position
(21:11)113PBLKSTOPPBLK Stop Position
(31:22)10Unused
Mode_Reg(12) (10:0)110HMASKSTARTVertical H Masking Start Position
(21:11)111HMASKSTOPVertical H Masking Stop Position
2210H1MASKPOLMasking Polarity for H1 during Vertical Blanking Period
(31:23)9Unused
Mode_Reg(13) (11:0)12550LMSTART0LM Counter Start Position 1
(23:12)124095LMSTART1LM Counter Start Position 2
(31:24)8Unused
REV. 0–14–
Page 15
AD9937
Table V. Mode_A (Addr 0x17) (continued)
BitBitRegister
AddrBreakdownWidthDefaultNameFunction
Mode_Reg(14) (7:0)81SCP1Sequence Change Position 1
(15:8)80SCP2Sequence Change Position 2
(23:16)80SCP3Sequence Change Position 3
(31:24)80SCP4Sequence Change Position 4
Mode_Reg(15) (11:0)121559HDLEN0HD Counter Length Value for Region 0
(13:12)20VTPPATSEL0VTP Pattern Select (0 = VTP0, 1 = VTP1, 2 = VTP2)
(16:14)30VTPREP0VTP Pulse Repetition Number in Region 0
1710LMPATSEL0LM Pattern Select for Region 0 (0 = LM0, 1 = LM1)
(19:18)20LMREP0LM Repetition Number in Region 0
2010SPHEN0Special H-Pattern Enable in Region 0
2111CLPOBEN0CLPOB Enable in Region 0
(31:22)10Unused
Mode_Reg(16) (11:0)121559HDLEN1HD Counter Length Value for Region 1
(13:12)20VTPPATSEL1VTP Pattern Select (0 = VTP0, 1 = VTP1, 2 = VTP2)
(16:14)32VTPREP1VTP Pulse Repetition Number in Region 1
1710LMPATSEL1LM Pattern Select for Region 1 (0 = LM0, 1 = LM1)
(19:18)23LMREP1LM Repetition Number in Region 1
2011SPHEN1Special H-Pattern Enable in Region 1
2111CLPOBEN1CLPOB Enable in Region 1
(31:22)10Unused
Mode_Reg(17) (11:0)121559HDLEN2HD Counter Length Value for Region 2
(13:12)20VTPPATSEL2VTP Pattern Select (0 = VTP0, 1 = VTP1, 2 = VTP2)
(16:14)32VTPREP2VTP Pulse Repetition Number in Region 2
1710LMPATSEL2LM Pattern Select for Region 2 (0 = LM0, 1 = LM1)
(19:18)23LMREP2LM Repetition Number in Region 2
2011SPHEN2Special H-Pattern Enable in Region 2
2111CLPOBEN2CLPOB Enable in Region 2
(31:22)10Unused
Mode_Reg(18) (11:0)121559HDLEN3HD Counter Length Value for Region 3
(13:12)20VTPPATSEL3VTP Pattern Select (0 = VTP0, 1 = VTP1, 2 = VTP2)
(16:14)32VTPREP3VTP Pulse Repetition Number in Region 3
1710LMPATSEL3LM Pattern Select for Region 3 (0 = LM0, 1 = LM1)
(19:18)23LMREP3LM Repetition Number in Region 3
2011SPHEN3Special H-Pattern Enable in Region 3
2111CLPOBEN3CLPOB Enable in Region 3
(31:22)10Unused
Mode_Reg(19) (11:0)121559HDLEN4HD Counter Length Value for Region 4
(13:12)20VTPPATSEL4VTP Pattern Select (0 = VTP0, 1 = VTP1, 2 = VTP2)
(16:14)32VTPREP4VTP Pulse Repetition Number in Region 4
1710LMPATSEL4LM Pattern Select for Region 4 (0 = LM0, 1 = LM1)
(19:18)23LMREP4LM Repetition Number in Region 4
2011SPHEN4Special H-Pattern Enable in Region 4
2111CLPOBEN4CLPOB Enable in Region 4
(31:22)10Unused
REV. 0
–15–
Page 16
AD9937
Table VI. Mode_B (Addr 0x18)
BitBitRegister
AddrBreakdownWidthDefault NameFunction
Mode_Reg(0)(11:0)12ENDADDRESSSub Word End Address
(23:12)12STARTADDRESSSub Word Start Address
(31:24)8MODE_Reg_AddrMode Register Address (Mode B = Addr 0x18)
(23:12)12130HDTOG2HD Toggle Position 2
(31:24)8Unused
Mode_Reg(3)(11:0)12830HDTOG3HD Toggle Position 3
(23:12)12865HDTOG4HD Toggle Position 4
(31:24)8Unused
Mode_Reg(4)(11:0)121559HDLASTLENHD Last Line Length
(22:12)11525VDLENVD Field Length
(26:23)40VDTOG1VD Toggle Position 1
(30:27)44VDTOG2VD Toggle Position 2
311Unused
Mode_Reg(5)(11:0)12808CLPOBTOG1CLPOB Toggle Position 1
(23:12)12822CLPOBTOG2CLPOB Toggle Position 2
(31:24)8Unused
Mode_Reg(6)(11:0)121543CLPOBTOG3CLPOB Toggle Position 3
(23:12)121557CLPOBTOG4CLPOB Toggle Position 4
(31:24)8Unused
Mode_Reg(7)(11:0)121HBLKTOG1HBLK Toggle Position 1
(23:12)12133HBLKTOG2HBLK Toggle Position 2
2411H1TOG12POLH1 Polarity between Toggle Positions 1 and 2
(31:25)7Unused
Mode_Reg(8)(11:0)12825HBLKTOG3HBLK Toggle Position 3
(23:12)12868HBLKTOG4HBLK Toggle Position 4
2410H1TOG34POLH1 Polarity between Toggle Positions 3 and 4
(31:25)7Unused
Mode_Reg(9)(11:0)126PBLKTOG1PBLK Toggle Position 1
(23:12)12143PBLKTOG2PBLK Toggle Position 2
(31:24)8Unused
Mode_Reg(10) (11:0)12831PBLKTOG3PBLK Toggle Position 3
(23:12)12878PBLKTOG4PBLK Toggle Position 4
(31:24)8Unused
Mode_Reg(11) (10:0)11510PBLKSTARTPBLK Start Position
(21:11)116PBLKSTOPPBLK Stop Position
(31:22)10Unused
Mode_Reg(12) (10:0)110HMASKSTARTVertical H Masking Start Position
(21:11)111HMASKSTOPVertical H Masking Stop Position
2210H1MASKPOLMasking Polarity for H1 during Vertical Blanking Period
(31:23)9Unused
Mode_Reg(13) (11:0)1299LMSTART0LM Counter Start Position 1
(23:12)12830LMSTART1LM Counter Start Position 2
(31:24)8Unused
REV. 0–16–
Page 17
AD9937
Table VI. Mode_B (Addr 0x18) (continued)
BitBitRegister
AddrBreakdownWidthDefaultNameFunction
Mode_Reg(14) (7:0)81SCP1Sequence Change Position 1
(15:8)80SCP2Sequence Change Position 2
(23:16)80SCP3Sequence Change Position 3
(31:24)80SCP4Sequence Change Position 4
Mode_Reg(15) (11:0)121559HDLEN0HD Counter Length Value for Region 0
(13:12)20VTPPATSEL0VTP Pattern Select (0 = VTP0, 1 = VTP1, 2 = VTP2)
(16:14)30VTPREP0VTP Pulse Repetition Number in Region 0
1710LMPATSEL0LM Pattern Select for Region 0 (0 = LM0, 1 = LM1)
(19:18)20LMREP0LM Repetition Number in Region 0
2010SPHEN0Special H-Pattern Enable in Region 0
2111CLPOBEN0CLPOB Enable in Region 0
(31:22)10Unused
Mode_Reg(16) (11:0)121559HDLEN1HD Counter Length Value for Region 1
(13:12)21VTPPATSEL1VTP Pattern Select (0 = VTP0, 1 = VTP1, 2 = VTP2)
(16:14)31VTPREP1VTP Pulse Repetition Number in Region 1
1711LMPATSEL1LM Pattern Select for Region 1 (0 = LM0, 1 = LM1)
(19:18)21LMREP1LM Repetition Number in Region 1
2010SPHEN1Special H-Pattern Enable in Region 1
2111CLPOBEN1CLPOB Enable in Region 1
(31:22)10Unused
Mode_Reg(17) (11:0)121559HDLEN2HD Counter Length Value for Region 2
(13:12)21VTPPATSEL2VTP Pattern Select (0 = VTP0, 1 = VTP1, 2 = VTP2)
(16:14)31VTPREP2VTP Pulse Repetition Number in Region 2
1711LMPATSEL2LM Pattern Select for Region 2 (0 = LM0, 1 = LM1)
(19:18)21LMREP2LM Repetition Number in Region 2
2010SPHEN2Special H-Pattern Enable in Region 2
2111CLPOBEN2CLPOB Enable in Region 2
(31:22)10Unused
Mode_Reg(18) (11:0)121559HDLEN3HD Counter Length Value for Region 3
(13:12)21VTPPATSEL3VTP Pattern Select (0 = VTP0, 1 = VTP1, 2 = VTP2)
(16:14)31VTPREP3VTP Pulse Repetition Number in Region 3
1711LMPATSEL3LM Pattern Select for Region 3 (0 = LM0, 1 = LM1)
(19:18)21LMREP3LM Repetition Number in Region 3
2010SPHEN3Special H-Pattern Enable in Region 3
2111CLPOBEN3CLPOB Enable in Region 3
(31:22)10Unused
Mode_Reg(19) (11:0)121559HDLEN4HD Counter Length Value for Region 4
(13:12)21VTPPATSEL4VTP Pattern Select (0 = VTP0, 1 = VTP1, 2 = VTP2)
(16:14)31VTPREP4VTP Pulse Repetition Number in Region 4
1711LMPATSEL4LM Pattern Select for Region 4 (0 = LM0, 1 = LM1)
(19:18)21LMREP4LM Repetition Number in Region 4
2010SPHEN4Special H-Pattern Enable in Region 4
2111CLPOBEN4CLPOB Enable in Region 4
(31:22)10Unused
REV. 0
–17–
Page 18
AD9937
SERIAL INTERFACE TIMING
All of the internal registers of the AD9937 are accessed through
a 3-wire serial interface. The 3-wire interface consists of a clock
(SCK), serial load (SLD), and serial data (SDA).
The AD9937 has three different register types that are configured
by the 3-wire serial interface pins. As described in Table VII,
the three register types are control registers, system registers,
and mode registers.
Table VII. Serial Interface Registers
RegisterAddressNo. of Registers
Control Registers0x00 to24-Bit Register at Each
0x12Address. See Table I.
VTP Sequence0x14Fourteen 32-Bit System
System RegistersRegisters at Address
0x14. See Table II.
H/LM System0x15Ten 32-Bit System
RegistersRegisters at Address
0x15. See Table III.
Shutter System0x16Five 32-Bit System
RegistersRegisters at Address
0x16. See Table IV.
Mode_A0x17Twenty 32-Bit Mode_A
Registers at Address
0x17. See Table V.
Mode_B0x18Twenty 32-Bit Mode_B
Registers at Address
0x18. See Table VI.
Control Register Serial Interface
The control register 3-wire interface timing requirements are
shown in Figure 5. Writing to control registers requires eight bits of
address data followed by 24 bits of configuration data between
each active low period of SLD for each address. The SLD signal
must be kept high for at least one full SCK cycle between successive writes to control registers.
System and Mode Register Serial Interface
The AD9937 provides two options for writing to system and
mode registers. The Page/Burst write option is used when all the
registers are going to be written to, whereas the Random Access
option is used when only one or a small contiguous sequence of
registers is going to be written to. As shown in Figure 6, the
protocol for writing to system and mode registers requires eight
bits for the address data, 12 bits for the start location, 12 bits
for the end location, and 32 bits for the register data.
Page/Burst Option
The AD9937 is automatically configured for Page/Burst mode if
both 12-bit STARTADDRESS and ENDADDRESS fields
equal 0. In this configuration, the AD9937 expects all registers
to be written to, therefore all register data must be clocked in
before the SLD pulse is asserted high. The SLD pulse is ignored
until all register data is clocked in. The Page/Burst option is
preferred when initially programming the system and mode
registers at startup.
Random Access Option
With the Random Access option, the 12-bit STARTADDRESS
and ENDADDRESS fields are typically used when writing to
one system or mode register or a small sequential number of
system or mode registers. In this mode, the address data selects
the system or mode register bank that is going to be accessed,
the 12-bit STARTADDRESS determines the first register to be
accessed, and the 12-bit ENDADDRESS determines the last
register to be accessed. Two examples of Random Access are
provided below (refer to Figure 6).
Example 1: Accessing Only One Register, HLM_Reg(6)
1. SDA BITS ARE INTERNALLY LATCHED ON THE RISING EDGES OF SCK.
2. THIS TIMING PATTERN MUST BE WRITTEN FOR EACH REGISTER WRITE WITH SLD REMAINING HIGH FOR AT
LEAST ONE FULL SCK PERIOD BEFORE ASSERTING SLD LOW AGAIN FOR THE NEXT REGISTER WRITE.
A5A6D22D21D3D2D1
t
DH
LS
D23
....
....
Figure 5. 3-Wire Serial Interface Timing for Control Registers
D0
t
LH
REV. 0–18–
Page 19
AD9937
8-BIT REG
ADDRESS [7:0]
SDA
SCK
SLD
A7A6A5A4A3A2A1
8 BIT
ADDRESS
1. ALL SLD PULSES ARE IGNORED UNTIL THE LAST BIT OF THE LAST DATA N WORD IS CLOCKED IN.
2. THE SLD PULSE MUST BE ASSERTED HIGH WHEN ALL SDA DATA TRANSMISSIONS HAVE BEEN COMPLETED.
ADDRESS [11:0]
A0
S10
S11
START LOCATION
12-BIT START
S9
S8
ADDRESS
12-BIT END
ADDRESS[11:0]
E9
S0
S1
S2
S3
E11
E10
END LOCATION
ADDRESS
1
Figure 6. System and Mode Register Writes
Internal Power-On Reset Circuitry
After power-on, the AD9937 automatically resets all internal
registers and performs 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 are ignored until the internal reset operation is completed.
VD Synchronous and Asynchronous Register Operation
There are two types of control registers, VD synchronous and
VD asynchronous, as indicated in the Address column of Table I.
Register writes to synchronous and asynchronous type registers
operate differently as described in the following sections. All
writes to system, Mode_A, and Mode_B registers occur
asynchronously.
32-BIT DATA 0 [31:0]32-BIT DATA N [31:0]
E3E2E1
E0
D31
D30
D29
DATA 0 [31:0]
1
D3D2D1
D0
D31
D30
12
D3D2D1
D29
DATA N [31:0]
D0
Asynchronous Register Operation
For asynchronous register writes, SDA data is stored directly
into the serial register at the rising edge of SLK. As a result,
register operation begins immediately after the register LSB has
been latched in on the rising edge of SCK.
VD Synchronous Register Operation
For VD synchronous type registers, SDA data is temporarily
stored in a buffer register upon completion of clocking in the
last register LSB. This data is held in the temporary buffer
register until the next rising edge of VD is applied. Once the
next rising edge of VD occurs, the buffered register data is
loaded into the serial register, and register operation begins.
See Figure 7.
Control registers at addresses 0x08, 0x09, 0x10, 0x11, and 0x12
are VD synchronous type registers.
HD
VCKM
VD
PROGRAMMING VD SYNCHRONOUS
TYPE REGISTERS MUST BE COMPLETED
AT LEAST FOUR VCKM CYCLES BEFORE
THE RISING EDGE OF VD.
Figure 7. VD Synchronous Type Register Writes
OPERATION OF VD SYNCHRONOUS TYPE
REGISTER WRITES BEGIN AT THE NEXT VD
RISING EDGE.
REV. 0
–19–
Page 20
AD9937
SYSTEM OVERVIEW
Figure 8 shows the typical system block diagram for the AD9937.
The CCD output is processed by the AD9937’s AFE circuitry,
which consists of a CDS, VGA, black level clamp, and A/D
converter. The digitized pixel information is sent to the digital
image processor chip, which performs the postprocessing and
compression. To operate the CCD, all CCD timing parameters
are programmed into the AD9937 from the system microprocessor, through the 3-wire serial interface. From the system
master clock, VCKM provided by the image processor or external crystal, the AD9937 generates all of the CCD’s horizontal
and vertical clocks and all internal AFE clocks.
CCD
V-DRIVE
OUT
BUFFER
CCD
TIMING
0.1F
ADC
CCDIN
C
IN
REGISTER
TIMING
GENERATOR
V
AD9937
OUT
DATA
DIGITAL
OUTPUTS
SERIAL
INTERFACE
DIGITAL IMAGE
PROCESSING
ASIC
Figure 8. Typical System Block Diagram, Master Mode
The H-drivers for H1(A–D) and H2(A,B), and RS are included
in the AD9937, allowing these clocks to be directly connected
to the CCD. H-drive voltage of up to 3.6 V is supported. An
external V-driver is required for the vertical transfer clocks and
sensor gate pulses.
Figure 9 shows the horizontal and vertical counter dimensions
for the AD9937. All internal horizontal and vertical clocking is
programmed using these dimensions to specify line and pixel
locations.
MAXIMUM FIELD DIMENSIONS
12-BIT HORIZONTALCOUNTER = 4096 PIXELS MAX
11-BIT VERTICAL COUNTER = 2048 LINES MAX
HD
VCKM
VD
Figure 9. Horizontal and Vertical Counters
MAX VD LENGTH IS 2048 LINES
MAX HD LENGTH IS 4095 PIXELS
Figure 10. Maximum VD/HD Dimensions
REV. 0–20–
Page 21
AD9937
ANALOG FRONT END DESCRIPTION AND OPERATION
The AD9937 AFE signal processing chain is shown in Figure 11.
Each processing step is essential in achieving a high quality 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 of
the AD9937.
DC RESTORE
SHD
SHP
PRECISION
TIMING
GENERATION
AD9937
6dB TO 40dB
VGA
10
VGA GAIN
REGISTER
DOUT
PHASE
0.1F
CCDIN
1.5V
SHP
CDS
SHD
Correlated Double Sampler
The CDS circuit samples each CCD pixel twice to extract the
video information and reject low frequency noise. The timing
diagram in Figure 13 illustrates how the two internally generated CDS clocks, SHP and SHD, are used to sample the
reference level and the data level, respectively, of the CCD
signal. The placement of the SHP and SHD sampling edges is
determined by the setting of the SHPLOC (addr 0x05) and
SHDLOC (addr 0x05) control registers. Placement of these two
clock edges is critical in achieving the best performance from
the CCD.
2V FULL
SCALE
CLAMP LEVEL
1.0F
REFT
2.0V
CLPOB
8
REGISTER
OUTPUT
DATA
LATCH
DOUT
PHASE
10
DOUT
8-BIT
DAC
DIGITAL
FILTER
CLPOB
V-H
TIMING
GENERATION
1.0F
REFB
1.0V
INTERNAL
VREF
ADC
OPTICAL BLACK
CLAMP
REV. 0
Figure 11. AFE Block Diagram
–21–
Page 22
AD9937
PRECISION TIMING HIGH SPEED TIMING
GENERATION
The AD9937 generates 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 RS, horizontal drivers H1(A–D) and H2(A, B), and
the CDS 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 13 master clock input
(VCKM) as a reference. This clock should be the same as
the CCD pixel clock frequency. Figure 12 illustrates how
the internal timing core divides the master clock period into
48 steps or edge positions. Using a 12 MHz VCKM frequency, the edge resolution of the precision timing core is
1.7 ns. A 24 MHz VCKM frequency can be applied to the
AD9937 where the AD9937 will internally divide the VCKM
frequency by 2. VCKM frequency division by 2 is controlled
by using the VCKM_DIVIDE control (addr 0x04) register.
POSITION
VCKM
P[0]P[48] = P[0]P[12]P[24]P[36]
High Speed Clock Programmability
Figure 13 shows how the high speed clocks RS, H1–H2, SHP, and
SHD are generated. The RS and H1 pulse have positive and negative edge programmability by using control registers (addr 0x06).
The H2 clock is always the inverse of H1. Table VIII summarizes
the high speed timing registers and the parameters for the high
speed clocks. Each register is six bits wide with the 2 MSB
used to select the quadrant region as outlined in Table IX.
Figure 14 shows the range and default locations of the high
speed clock signals.
H-Driver and RS Outputs
In addition to the programmable timing positions, the AD9937
features on-chip output drivers for the RS and H1–H2 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 H1DRV and H2DRV
control registers (addr 0x07). The RS drive current is adjustable
using the RSDRV control register (addr 0x07). The H1DRV,
H2DRV, and RSDRV registers are adjustable in 1.75 mA increments. All DRV registers have setting of 0 equal to OFF or
three-state, and the maximum setting of 7.
t
VCKMDLY
1 PIXEL
PERIOD
PIXEL CLOCK PERIOD IS DIVIDED INTO 48 POSITIONS, PROVIDING FINE EDGE RESOLUTION FOR HIGH SPEED CLOCKS.
THERE IS A FIXED DELAY FROM THE VCKM INPUT TO THE INTERNAL PIXEL PERIOD POSITIONS (
t
VCKMDLY
= 6ns TYP).
Figure 12. High Speed Clock Resolution from VCKM Master Clock
3
CCD
SIGNAL
(INTERNAL)
CDS
RS
H1
H2
12
56
PROGRAMMABLE CLOCK INFORMATION
1. RG RISING EDGE (PROGRAMMABLE AT CONTROL REGISTER RSPOSLOC (ADDR 0x06))
2. RG FALLING EDGE (PROGRAMMABLE AT CONTROL REGISTER RSNEGLOC (ADDR 0x06))
3. SHP SAMPLE LOCATION (PROGRAMMABLE AT CONTROL REGISTER SHPLOC (ADDR 0x05))
4. SHD SAMPLE LOCATION (PROGRAMMABLE AT CONTROL REGISTER SHDLOC (ADDR 0x05))
5. H1 RISING EDGE LOCATION (PROGRAMMABLE AT CONTROL REGISTER H1POSLOC (ADDR 0x06))
6. H1 NEGATIVE EDGE LOCATION (PROGRAMMABLE AT CONTROL REGISTER H1NEGLOC (ADDR 0x06))
7. H2 IS ALWAYS THE INVERSE OF H1.
4
Figure 13. High Speed Clock Programmable Locations
REV. 0–22–
Page 23
AD9937
Table VIII. RS, H1, SHP, SHD, and DOUTPHASE Timing Parameters
Bit Width
Register Name*(Bits)Register TypeRangeDescription
RSPOSLOC 6Control (Addr 0x06)0–47 Edge LocationFalling Edge Location for RS
RSNEGLOC 6Control (Addr 0x06)0–47 Edge LocationFalling Edge Location for RS
H1POSLOC 6Control (Addr 0x06)0–47 Edge LocationPositive Edge Location for H1
H1NEGLOC 6Control (Addr 0x06)0–47 Edge LocationNegative Edge Location for H1
SHPLOC 6Control (Addr 0x05)0–47 Edge LocationSample Location for SHP
SHDLOC 6Control (Addr 0x05)0–47 Edge LocationSample Location for SHD
DOUTPHASE 6Control (Addr 0x05)0–47 Edge LocationPhase Location of Data Output [9:0]
*The 2 MSB bits are used to select the quadrant.
Table IX. Precision Timing Edge Locations for RS, H1, SHP, SHD, and DOUTPHASE
QuadrantRS Rising EdgeRS Falling Edge
Signal Name(Range)RSPOSLOCRSNEGLOC
RSIP[0] to P[11]000000 to 001011000000 to 001011
IIP[12] to P[23]010000 to 011011010000 to 011011
IIIP[24] to P[35]100000 to 101011100000 to 101011
IVP[36] to P[47]110000 to 111011110000 to 111011
QuadrantH1 Rising EdgeH1 Falling Edge
Signal Name(Range)H1POSLOCH1NEGLOC
H1IP[0] to P[11]000000 to 001011000000 to 001011
IIP[12] to P[23]010000 to 011011010000 to 011011
IIIP[24] to P[35]100000 to 101011100000 to 101011
IVP[36] to P[47]110000 to 111011110000 to 111011
CDS (Internal)IP[0] to P[11]000000 to 001011000000 to 001011
IIP[12] to P[23]010000 to 011011010000 to 011011
IIIP[24] to P[35]100000 to 101011100000 to 101011
IVP[36] to P[47]110000 to 111011110000 to 111011
QuadrantDOUT Rising EdgeDOUT Falling Edge
Signal Name(Range)DOUTPHASE(Not Programmable)
Data Output[9:0]IP[0] to P[11]000000 to 001011DOUTPHASE + 24 Steps
IIP[12] to P[23]010000 to 011011DOUTPHASE + 24 Steps
IIIP[24] to P[35]100000 to 101011DOUTPHASE + 24 Steps
IVP[36] to P[47]110000 to 111011DOUTPHASE + 24 Steps
REV. 0
–23–
Page 24
AD9937
POSITION
PIXEL
PERIOD
RS
H1
CDS
(INTERNAL)
CCD
SIGNAL
P[0]
Hr[0]
P[24]P[12]P[36]
RSf[12]RSr[0]
Hf[24]
SHP[24]
t
S1
P[48] = P[0]
SHD[48]
Figure 14. High Speed Clock Default and Programmable Locations
t
H1
H2
RISE
t
<
t
PD
RISE
H1
FIXED CROSSOVER VOLTAGE
t
PD
H2
Figure 15. H-Clock Inverse Phase Relationship
P[0]P[48] = P[0]
PIXEL
PERIOD
VCLK
t
OD
DOUT
1. DOUTPHASE REGISTER (ADDR 0x05) CAN BE USED TO SHIFT THE PHASE OF VCLK AND DOUT TOGETHER WITH RESPECT TO P[0].
2. DOUT[9:0] CAN BE INDEPENDENTLY DELAYED WITH RESPECT TO VCLK BY USING DOUT_DELAY REGISTER (ADDR 0x05).
P[12]P[24]P[36]
Figure 16. Digital Output Phase Adjustment
REV. 0–24–
Page 25
AD9937
MASTER AND SLAVE MODE OPERATION
The AD9937 defaults at power up into slave mode operation.
During slave mode operation, the VD and HD pins are configured as inputs for external VD and HD signals. The AD9937
can be configured into master mode operation to output the
VD and HD signals by programming MASTER = 1 (control
addr 0x05).
HORIZONTAL AND VERTICAL TIMING
The internal VD and HD synchronization timing is configured
by using the registers in Table X. As shown in Figure 17, the
HD and VD clock positions are referenced to the 12-bit
H-counter and 11-bit V-counter, respectively. This allows for
a maximum of 4096 horizontal pixels by 2048 vertical
line resolution.
The AD9937 provides programmability for two HD pulses per
line with the ability to independently set the last line length by
using the HDLASTLEN register (Mode_Reg(4)). Additionally,
the HDLENx (where x = 0, 1, 2, 3, 4 representing CCD regions)
registers can be used to set different line lengths for each CCD
region. As shown in Figure 31, up to five unique CCD regions
may be specified.
Table X. HD and VD Registers
Length
Register Name(Bits)Register TypeRangeDescription
VDLEN11Mode_Reg(4)0–2047 Line Number11-Bit VD Counter Length
VDTOG14Mode_Reg(4)0–15 Pixel LocationVD Toggle Position 1. See Figure 17.
VDTOG24Mode_Reg(4)0–15 Pixel LocationVD Toggle Position 2. See Figure 17.
HDTOG112Mode_Reg(2)0–4095 Pixel LocationHD Toggle Position 1. See Figure 17.
HDTOG212Mode_Reg(2)0–4095 Pixel LocationHD Toggle Position 2. See Figure 17.
HDTOG312Mode_Reg(3)0–4095 Pixel LocationHD Toggle Position 3. See Figure 17.
HDTOG412Mode_Reg(3)0–4095 Pixel LocationHD Toggle Position 4. See Figure 17.
HDLASTLEN12Mode_Reg(4)0–4095 Pixel LocationHD Last Line Length. See Figure 17.
HDLEN012Mode_Reg(15)0–4095 Pixel Location12-Bit HD Counter Length Value for CCD Region 0
HDLEN112Mode_Reg(16)0–4095 Pixel Location12-Bit HD Counter Length Value for CCD Region 1
HDLEN212Mode_Reg(17)0–4095 Pixel Location12-Bit HD Counter Length Value for CCD Region 2
HDLEN312Mode_Reg(18)0–4095 Pixel Location12-Bit HD Counter Length Value for CCD Region 3
HDLEN412Mode_Reg(19)0–4095 Pixel Location12-Bit HD Counter Length Value for CCD Region 4
VDHD_INVERT1Control 0x04HIGH/LOWVD and HD Inversion Control
Individual HMASK Sequence
The HMASK programmable timing shown in Figure 18 provides two HMASK toggle positions and an H1MASK polarity
setting. These registers can be used to disable the horizontal
H1 and H2 outputs during the vertical transfer period. As shown
in Figure 18, the H2(A, B) outputs are always the opposite
polarity of the H1(A–D) outputs. The H1MASKSTART and
H1MASKSTOP registers reference the 11-bit VD counter.
Individual PBLK Sequences
Up to two individual PBLK pulses can be programmed per line
using the registers in Table XI. During the time PBLK is active,
the DOUT[9:0] data is fixed at the level set in the PBLK_LEVEL
(control addr 0x03) register. Figures 19, 20, and 21 provide
examples of PBLK registers described in Table XI.
REV. 0
–25–
Page 26
AD9937
VDLEN
11-BIT
VD COUNTER
12-BIT
HD COUNTER
11-BIT
VD COUNTER
VD
000
HDLENx
123
VD
456
HD
*
X = 0, 1, 2, 3, 4 REPRESENTING CCD REGIONS
PROGRAMMABLE CLOCK POSITIONS
1. VDHD_INVERT (PROGRAMMABLE AT CONTROL 0x04)
2. VDTOG1 (PROGRAMMABLE AT MODE_REG(4))
3. VDTOG2 (PROGRAMMABLE AT MODE_REG(4))
4. HDTOG1 (PROGRAMMABLE AT MODE_REG(2))
001002003
*
7
OPTIONAL SECOND HD PULSE PER LINE
Figure 17. VD and HD Programmable Locations
N – 1
5. HDTOG2 (PROGRAMMABLE AT MODE_REG(2))
6. HDTOG3 (PROGRAMMABLE AT MODE_REG(3))
7. HDTOG4 (PROGRAMMABLE AT MODE_REG(3))
N 2048
HDLASTLEN
000
001
HMASK
H1(A–D)
H1(A–D)
H1(A, B)
12
3
PROGRAMMABLE CLOCK POSITIONS
1. HMASKSTART (PROGRAMMABLE AT MODE_REG(12))
2. HMASKSTOP (PROGRAMMABLE AT MODE_REG(12))
3. H1MASKPOL (PROGRAMMABLE AT MODE_REG(12))
THE POLARITY OF H1(A–D) DURING BLANKING IS PROGRAMMABLE
(H2(A, B) IS ALWAYS THE OPPOSITE POLARITY OF H1 (A–D))
Figure 18. Programmable Clock Positions for HMASK
Table XI. PBLK Registers
LengthRegister
Register Name(Bits)TypeRangeDescription
PBLK_LEVEL1Control 0x03HIGH/LOW0 = Blank Output Data to Zero,
1 = Blank Output Data to REFBLACK
PBLKTOG112Mode_Reg(9)0–4095 Pixel LocationsSets PBLK Toggle Position 1 within the Line
PBLKTOG212Mode_Reg(9)0–4095 Pixel LocationsSets PBLK Toggle Position 2 within the Line
PBLKTOG312Mode_Reg(10)0–4095 Pixel LocationsSets PBLK Toggle Position 3 within the Line
PBLKTOG412Mode_Reg(10)0–4095 Pixel LocationsSets PBLK Toggle Position 4 within the Line
PBLKSTART11Mode_Reg(11)0–2047 Line NumberSets the Line Number the PBLK Pulse Will Start In
PBLKSTOP11Mode_Reg(11)0– 2047 Line NumberSets the Line Number the PBLK Pulse Will Stop In
REV. 0–26–
Page 27
12-BIT
(
))
HD COUNTER
AD9937
12-BIT
HD COUNTER
PBLK
11-BIT
VD COUNTER
12-BIT
HD COUNTER
PBLK
1
PROGRAMMABLE CLOCK POSITIONS
1. PBLKTOG1 (PROGRAMMABLE AT MODE_REG(9))
2. PBLKTOG2 (PROGRAMMABLE AT MODE_REG(9))
3. PBLKTOG3 (PROGRAMMABLE AT MODE_REG(10))
4. PBLKTOG4
2
PROGRAMMABLE AT MODE_REG(10
3
4
Figure 19. PBLK Timing
HDLEN = 1500
PBLKTOG1 = 500
1. PBLKTOG1 = 500
2. PBLKTOG2 = 785
3. PBLKTOG3 = 4095
4. PBLKTOG4 = 4095
5. THIS PBLK PULSE SEQUENCE IS USED IN THE EXAMPLE BELOW.
VD
500 785500 785500500 785500 785500 785
PBLKTOG2 = 785
000001002003NN – 1N – 2N – 3N – 4
PBLKSTART
1. PBLKSTART = N – 2
2. PBLKSTOP = 001
3. THIS EXAMPLE SHOWS HOW PBLK IS LOW IN THE VERTICAL BLANKING REGION FROM PBLKTOG1 IN LINE PBLKSTART UNTIL PBLKTOG2 IN LINE PBLKSTOP.
AS SHOWN IN THE ABOVE FIGURE, PBLK REMAINS LOW FROM PBLKTOG1 TO PBLKTOG2.
PBLKSTOP
Figure 20. Example of PBLK Applied in Vertical Blanking Region Using PBLKSTART and PBLKSTOP Registers
REV. 0
–27–
Page 28
AD9937
(
))
11-BIT
VD COUNTER
12-BIT
HD COUNTER
VD
HD
PBLK
001002003004000
Figure 21. Example with PBLKSTOP = PBLKSTART = 2048
Controlling CLPOB Clamp Pulse Timing
Up to two individual CLPOB pulses can be programmed per line
using the CLPOBTOGx (x = 1, 2, 3, 4) registers in Table XII.
As shown in Figure 19, these registers reference the 12-bit HD
counter. Additional CLPOBENn (n = 0, 1, 2, 3, 4) registers are
Table XII. CLPOB Registers
NN – 1
provided that allow for independently enabling and disabling
the CLPOB pulse in each region of the CCD. Figure 23 shows
an example of disabling the CLPOB pulse while operating in
CCD region 1.
LengthRegister
Register Name(Bits)TypeRangeDescription
CLPOBTOG112Mode_Reg(5)0–4095 Pixel LocationFirst Toggle Position for CLPOB
CLPOBTOG212Mode_Reg(5)0–4095 Pixel LocationFirst Toggle Position for CLPOB
CLPOBTOG312Mode_Reg(6)0–4095 Pixel LocationFirst Toggle Position for CLPOB
CLPOBTOG412Mode_Reg(6)0–4095 Pixel LocationFirst Toggle Position for CLPOB
CLPOBEN01Mode_Reg(15)Enabled/DisabledCCD Region 0 CLPOB Enable Disable Control
CLPOBEN11Mode_Reg(16)Enabled/DisabledCCD Region 1 CLPOB Enable Disable Control
CLPOBEN21Mode_Reg(17)Enabled/DisabledCCD Region 2 CLPOB Enable Disable Control
CLPOBEN31Mode_Reg(18)Enabled/DisabledCCD Region 3 CLPOB Enable Disable Control
CLPOBEN41Mode_Reg(19)Enabled/DisabledCCD Region 4 CLPOB Enable Disable Control
12-BIT
HD COUNTER
HD
CLPOB
PROGRAMMABLE CLOCK POSITIONS
1. CLPOBTOG1 (PROGRAMMABLE AT MODE_REG(5))
2. CLPOBTOG2 (PROGRAMMABLE AT MODE_REG(5))
3. CLPOBTOG3 (PROGRAMMABLE AT MODE_REG(6))
4. CLPOBTOG4
PROGRAMMABLE AT MODE_REG(6
3412
Figure 22. CLPOB Toggle Positions
REV. 0–28–
Page 29
AD9937
CCD REGION 0
VD
HD
CLPOB
Figure 23. Example with CLPOBEN1 = 0
Vertical Sensor Transfer Gate Timing
The vertical transfer sensor gate (TG) pulses are used to transfer the pixel charges from the light-sensitive image area into the
light-shielded vertical registers. When a mechanical shutter is
not being used, this transfer effectively ends the exposure
period during the image acquisition. From the light-shield
vertical registers, the image is then read out line by line using
the vertical transfer pulses in conjunction with the high speed
horizontal clocks.
The AD9937 provides four programmable vertical transfer gate
pulses (TG1A, TG1B, TG3A, and TG3B). Table XIII lists the
TG registers. Two unique TG pulses can be preprogrammed
using the TGTOG_x (x = 0, 1) registers. As shown in Figure 24,
these toggle registers reference the 12-bit H counter for resolution control at the pixel level. Once the toggle positions have
been programmed, the TGPATSELx (x = 0, 1) can be used to
select which of the two TG pulses will be output on the TG1A/
B and TG3A/B pins. The TG1A/B and TG3A/B outputs are
selected as a group. As a result, the TG1A and TG1B outputs
will always be the same. This also applies for the TG3A and
TG3B outputs. For example, if TGPATSEL0 = 0, TG1A and
TG1B will have the outputs provided by the TGTOG1_0 and
TGTOG2_0 registers.
The TGMASK register can be used to individually mask (disable)
any one of the TG outputs. For example, if TGMASK = 1, the
TG1A will not be output. All TG outputs can be disabled by
setting TGEN = 0.
CCD REGION 1
SHUTTER TIMING CONTROL
CCD REGION 2
CCD image exposure is controlled through use of the substrate
clock signal (OFD), which pulses the CCD substrate to clear
out accumulated charge. The AD9937 supports two types of
OFD shutter timing: normal shutter mode and high precision
shutter mode. The registers used for OFD programming are
described in Table XIV.
Normal Shutter Mode
Figure 24 shows the VD and OFD output for normal shutter
mode. Programming the OFD outputs is similar to programming the TG pulse whereas two unique OFD pulses can be
preprogrammed using the OFDTOG_x (x = 0, 1) registers. The
OFDTOG_x registers reference the 12-bit HD counter as shown
in Figure 24. Once the toggle positions have been programmed,
the OFDPATSEL register is used to select which of the two
preprogrammed OFD pulses will be output. The OFD will pulse
once per line for as many lines set in the OFDNUM register.
High Precision Shutter Mode
High precision shuttering is controlled in the same way as normal shuttering but requires a second set of shutter registers. In
this mode, the OFD still pulses once per line, but the last OFD
in the field will have an additional OFD pulse whose location is
determined by the OFDHPTOG1 and OFDHPTOG2 registers.
An example of this is shown in Figure 25. Finer resolution of
the exposure time is possible using this mode. Leaving both
OFDHPTOG registers set to 4095 disables the high precision
shutter mode (default setting).
Table XIII. TG Registers
LengthRegister
Register Name(Bits)TypeRangeDescription
TGEN1Control 0x10High/LowTG Output Enable Control (0 = Disable, 1 = Enable)
TGTOG1_012Shut_Reg(1)0–4095 Pixel LocationTG0 Pulse Toggle Position 1
TGTOG2_012Shut_Reg(1)0–4095 Pixel LocationTG0 Pulse Toggle Position 2
TGTOG1_112Shut_Reg(2)0–4095 Pixel LocationTG1 Pulse Toggle Position 1
TGTOG2_112Shut_Reg(2)0–4095 Pixel LocationTG1 Pulse Toggle Position 2
TGACTLINE7Mode_Reg(1)0–127 Pixel LocationLine in Field where TG Outputs are Active
TGPATSEL01Mode_Reg(1)High/LowTG1 A/B Pattern Selector (0 = TG0, 1 = TG1)
TGPATSEL11Mode_Reg(1)High/LowTG3 A/B Pattern Selector (0 = TG0, 1 = TG1)
TGMASK4Mode_Reg(1)4 Individual BitsTG Masking Control (0 = No Masking, 1 = Mask TG1A,
2 = Mask TG1B, 3 = Mask TG3A, 4 = Mask TG3B)
REV. 0
–29–
Page 30
AD9937
Table XIV. OFD Registers
LengthRegister
Register Name(Bits)TypeRangeDescription
OFDEN1Control 0x10High/LowOFD Output Enable Control (0 = Disable, 1 = Enable)
OFDNUM11Control 0x100–2048 PulsesTotal Number of OFD Pulses per Field
OFDHPTOG112Control 0x110–4095 Pixel LocationsHigh Precision Toggle Position 1. See Figure 24.
OFDHPTOG212Control 0x110–4095 Pixel LocationsHigh Precision Toggle Position 2. See Figure 24.
OFDTOG1_012Shut_Reg(3)0–4095 Pixel LocationsOFD0 Pulse Toggle Position 1
OFDTOG2_012Shut_Reg(3)0–4095 Pixel LocationsOFD0 Pulse Toggle Position 2
OFDTOG1_112Shut_Reg(4)0–4095 Pixel LocationsOFD1 Pulse Toggle Position 1
OFDTOG2_112Shut_Reg(4)0–4095 Pixel LocationsOFD1 Pulse Toggle Position 2
OFDPATSEL1Mode_Reg(1)High/LowOFD Pattern Selector (0 = OFD0, 1 = OFD1)
11-BIT
VD COUNTER
12-BIT
HD COUNTER
TG1A
TG1B
TG3A
TG3B
OFD
Figure 24. Horizontal Timing Example with TGACTLINE = 1 and OFDNUM = 2
000
VD
HD
PROGRAMMABLE CLOCK POSITIONS
1. TGACTLINE (PROGRAMMABLE AT MODE_REG(1))
2. TGTOG1_0 (PROGRAMMABLE AT SHUT_REG(1))
3. TGTOG2_0 (PROGRAMMABLE AT SHUT_REG(1))
4. TGTOG1_1 (PROGRAMMABLE AT SHUT_REG(2))
001002003
1
23
45
6
7
N – 1N 2048
LAST LINE
t
EXP
5. TGTOG2_1 (PROGRAMMABLE AT SHUT_REG(2))
6. OFDTOG1_0 (PROGRAMMABLE AT SHUT_REG(3))
7. OFDTOG2_0 (PROGRAMMABLE AT SHUT_REG(3))
000
001
VD
HD
TG1A
TG1B
TG3A
TG3B
OFD
PROGRAMMABLE CLOCK POSITIONS
1. OFDHPTOG1 (PROGRAMMABLE AT CONTROL REGISTER 0x11)
2. OFDHPTOG2 (PROGRAMMABLE AT CONTROL REGISTER 0x11)
Figure 25. High Precision
LAST LINE
12
t
EXP
SECOND OFD PULSE ADDED IN THE
LAST LINE FOR GREATER EXPOSURE
CONTROL PRECISION
REV. 0–30–
Page 31
AD9937
Controlling LM Pulse Timing
The AD9937 provides an LM output pulse that is fully programmable by using the registers in Table XV. Two unique sets of LM
pulses can be preprogrammed using the LMLENx, LMTOG1_x,
and LMTOG2_x (x = 0, 1) registers. Once these pulses are
preprogrammed, they can be individually selected to be output
in any of the five CCD regions by using the LMPATSELn
register (n = 0, 1, 2, 3, 4). The number of repetitions can also be
individually programmed for each CCD region by using the
LMREPn register (n = 0, 1, 2, 3, 4).
The 12-bit H counter and 8-bit LM counters are used for configuring the LM pulse. The 8-bit LM counter resets to 0 when
Table XV. LM Registers
LengthRegister
Register Name(Bits)TypeRangeDescription
LM_INVERT1Control 0x04High/LowLM Inversion Control (1 = Invert Programmed LM)
LMSTART0*12Mode_Reg(13)0–4095 PixelsLM Counter Start Position 1
LMSTART1*12Mode_Reg(13)0–4095 PixelsLM Counter Start Position 2
LMLEN08HLM_Reg(8)0–255 PixelsLM Counter Length for LM0
LMTOG1_08HLM_Reg(8)0–255 PixelsLM0 Toggle Position 1
LMTOG2_08HLM_Reg(8)0–255 PixelsLM0 Toggle Position 2
LMLEN18HLM_Reg(9)0–255 PixelsLM Counter Length for LM1
LMTOG1_18HLM_Reg(9)0–255 PixelsLM1 Toggle Position 1
LMTOG2_18HLM_Reg(9)0–255 PixelsLM1 Toggle Position 2
the 12-bit H counter resets to 0 set by the HDLEN register.
The LMSTART0 and LMSTART1 positions reference the 12bit H counter value zero. The 8-bit LM counter begins counting
when LMSTART0 is reached; it counts up to the value set in
the LMLENx register, as shown in Figure 26. The LM pulse
toggle positions reference the 8-bit LM counter.
Figures 26 and 27 provide examples of programming the LM
pulses. Figure 26 shows an example when LMSTART1 is less
than HDLEN. In this case, multiple sets of LM pulses can be
output between the HDLEN lengths. The number of sets is
determined by the value of HDLEN and LMSTART1. Figure 27
shows that only one set of LM pulses will be output when
LMSTART1 is greater than HDLEN.
LMPATSEL01Mode_Reg(15)High/LowSelects CCD Region 0 LM Pattern (0 = LM0, 1 = LM1)
LMREP02Mode_Reg(15)0–3 LM RepetitionsLM Repetition Number in CCD Region 0
LMPATSEL11Mode_Reg(16)High/LowSelects CCD Region 1 LM Pattern (0 = LM0, 1 = LM1)
LMREP12Mode_Reg(16)0–3 LM RepetitionsLM Repetition Number in CCD Region 1
LMPATSEL21Mode_Reg(17)High/LowSelects CCD Region 2 LM Pattern (0 = LM0, 1 = LM1)
LMREP22Mode_Reg(17)0–3 LM RepetitionsLM Repetition Number in CCD Region 2
LMPATSEL31Mode_Reg(18)High/LowSelects CCD Region 3 LM Pattern (0 = LM0, 1 = LM1)
LMREP32Mode_Reg(18)0–3 LM RepetitionsLM Repetition Number in CCD Region 3
LMPATSEL41Mode_Reg(19)High/LowSelects CCD Region 4 LM Pattern (0 = LM0, 1 = LM1)
LMREP42Mode_Reg(19)0–3 LM RepetitionsLM Repetition Number in CCD Region 4
*LMSTART0 and LMSTART1 reference the 12-bit HD counter.
REV. 0
–31–
Page 32
AD9937
HD COUNTER
LM COUNTER
12-BIT
8-BIT
LMx
LMLENx
1
12
3
1
2
= 3
LMREPn
LMSTART0
NOTES
1
x = 0, 1 (TWO UNIQUE SETS OF LM OUTPUTS CAN BE PROGRAMMED)
2
n = 0, 1, 2, 3, 4 (INDIVIDUAL REPETITION CONTROL FOR EACH CCD REGION)
LM PULSE SET 1
LMSTART1
Figure 26. Example of LM Pulse with LMSTART1 < HDLEN
12-BIT
HD COUNTER
LMLENx
8-BIT
LM COUNTER
LMREPn = 3
LMx
LMSTART0
LM PULSE SET 1
Figure 27. Example of LM Pulse with LMSTART1 > HDLEN
SPECIAL HORIZONTAL PATTERN TIMING
The AD9937 provides the ability to interrupt the normal horizontal H1(A–D) and H2(A, B) clocking in order to apply a
special pattern on these outputs. This special horizontal pattern
timing occurs during the period when the LM outputs are active.
Table XVI lists the registers used to program the special H
patterns. Figure 28 provides an example of a special H pattern
being applied to the H1A output.
The timing diagram shown in Figure 28 identifies the registers
associated with outputting the special H patterns. Although only
LM PULSE SET 2
PROGRAMMABLE CLOCK POSITIONS
1. LM_INVERT (PROGRAMMABLE AT CONTROL 0x04)
2. LMTOG1_x (PROGRAMMABLE AT HLM_REG(8))
3. LMTOG2_x (PROGRAMMABLE AT HLM_REG(8))
the H1A output is shown, the same special H timing can be
independently configured on the remaining horizontal outputs
by using the registers described in Table XVI. As shown in
Figure 28, the special H1A output begins when SPHSTARTx
is reached. It is important to note that there are two SPHSTART
registers. If SPHPATSEL = 0, the SPHSTART0 register will
be used, whereas if SPHPATSEL = 1, the SPHSTART1 register will be used. The special H patterns can be enabled and
disabled for each of the five CCD regions by using the SPHENx
(x = 0, 1, 2, 3, 4).
REV. 0–32–
Page 33
AD9937
MASKING H1 AND H2 OUTPUTS
The H1 and H2 outputs can be masked during the horizontal
and vertical transfers as shown in Figures 29 and 30.
Horizontal Masking
The H1 clocks are masked with the polarity set by the
H1MASKPOL register as shown in Figure 29. The H2 outputs
will always be the opposite polarity of H1. The H1 and H2 outputs are masked from HDLEN + 1 to HBLKTOG1 position
when HDLASTLEN is the same as HDLEN. In the case when
HDLASTLEN is greater than HDLEN, the H1 and H2 outputs
Table XVI. Special H Pattern Registers
will be masked during the entire last line. It is recommended to
always program HBLKTOG3 and HBLKTOG4 to 4095 when
only one H-blanking in a line is required. It is also recommended
to program HBLKTOG1 < HBLKTOG2 < HBLKTOG3 <
HBLKTOG4.
Vertical Masking
As shown in Figure 30, the H1 and H2 outputs remain masked
if the horizontal HMASK is followed by the vertical HMASK
region or if the vertical HMASK region is followed by the horizontal HMASK region.
LengthRegister
Register Name(Bits)TypeRangeDescription
1
HBLKTOG1
HBLKTOG2
HBLKTOG3
HBLKTOG4
12Mode_Reg(7)0–4095 Pixel LocationsHBLK Toggle Position 1
1
12Mode_Reg(7)0–4095 Pixel LocationsHBLK Toggle Position 2
1
12Mode_Reg(8)0–4095 Pixel LocationsHBLK Toggle Position 3
1
12Mode_Reg(8)0–4095 Pixel LocationsHBLK Toggle Position 4
H1APOL1HLM_Reg(1)High/LowH1A Special H Pattern Start Polarity
H1BPOL1HLM_Reg(1)High/LowH1B Special H Pattern Start Polarity
H1CPOL1HLM_Reg(1)High/LowH1C Special H Pattern Start Polarity
H1DPOL1HLM_Reg(1)High/LowH1D Special H Pattern Start Polarity
H2APOL1HLM_Reg(1)High/LowH2A Special H Pattern Start Polarity
H2BPOL1HLM_Reg(1)High/LowH2B Special H Pattern Start Polarity
SPHSTART0
SPHSTART1
2
8HLM_Reg(8)0–255 Pixel LocationsLM Pattern #0 (LM0) Special H Pulse Start Position
2
8HLM_Reg(9)0–255 Pixel LocationsLM Pattern #1 (LM1) Special H Pulse Start Position
SPH1A16HLM_Reg(2)6 Individual BitsH1A Special H Pattern during LM Repetition 1
SPH1B16HLM_Reg(2)6 Individual BitsH1B Special H Pattern during LM Repetition 1
SPH1C16HLM_Reg(2)6 Individual BitsH1C Special H Pattern during LM Repetition 1
SPH1D16HLM_Reg(3)6 Individual BitsH1D Special H Pattern during LM Repetition 1
SPH2A16HLM_Reg(3)6 Individual BitsH2A Special H Pattern during LM Repetition 1
SPH2B16HLM_Reg(3)6 Individual BitsH2B Special H Pattern during LM Repetition 1
SPH1A26HLM_Reg(4)6 Individual BitsH1A Special H Pattern during LM Repetition 2
SPH1B26HLM_Reg(4)6 Individual BitsH1B Special H Pattern during LM Repetition 2
SPH1C26HLM_Reg(4)6 Individual BitsH1C Special H Pattern during LM Repetition 2
SPH1D26HLM_Reg(5)6 Individual BitsH1D Special H Pattern during LM Repetition 2
SPH2A26HLM_Reg(5)6 Individual BitsH2A Special H Pattern during LM Repetition 2
SPH2B26HLM_Reg(5)6 Individual BitsH2B Special H Pattern during LM Repetition 2
SPH1A36HLM_Reg(6)6 Individual BitsH1A Special H Pattern during LM Repetition 3
SPH1B36HLM_Reg(6)6 Individual BitsH1B Special H Pattern during LM Repetition 3
SPH1C36HLM_Reg(6)6 Individual BitsH1C Special H Pattern during LM Repetition 3
SPH1D36HLM_Reg(7)6 Individual BitsH1D Special H Pattern during LM Repetition 3
SPH2A36HLM_Reg(7)6 Individual BitsH2A Special H Pattern during LM Repetition 3
SPH2B36HLM_Reg(7)6 Individual BitsH2B Special H Pattern during LM Repetition 3
SPHEN01Mode_Reg(15)High/LowSpecial H Pattern Enable in CCD Region 0
SPHEN11Mode_Reg(16)High/LowSpecial H Pattern Enable in CCD Region 1
SPHEN21Mode_Reg(17)High/LowSpecial H Pattern Enable in CCD Region 2
SPHEN31Mode_Reg(18)High/LowSpecial H Pattern Enable in CCD Region 3
SPHEN41Mode_Reg(19)High/LowSpecial H Pattern Enable in CCD Region 4
NOTES
1
The HBLKTOGx toggle positions reference the 12-bit HD counter.
2
The SPHSTART0 and SPHSTART1 toggle positions reference the 8-bit LM counter.
REV. 0
–33–
Page 34
AD9937
12-BIT
HD COUNTER
8-BIT
LM COUNTER
H1A
LMSTART0
HBLKTOG1SPHSTARTx
23456
HBLKTOG2
HBLKTOG3
LMSTART1
HBLKTOG3
PROGRAMMING NOTES
1. THERE ARE TWO SPHSTART REGISTERS. THEY ARE SPHSTART0 AND SPHSTART1.
SPHSTART0 IS USED WHEN THE LM0 PULSE IS SELECTED BY SETTING LMPATSEL = 0.
SPHSTART1 IS USED WHEN THE LM1 PULSE IS SELECTED BY SETTING LMPATSEL = 1.
2. THIS REGION REPRESENTS NORMAL H1A OUTPUTS.
3. THIS REGION REPRESENTS SPECIAL H1A PATTERN BEING OUTPUT DURING THE LM REP 1.
THE SPH1A1 REGISTER IS USED TO SET THE SPECIAL H1A PATTERN IN THIS REGION.
4. THIS REGION REPRESENTS SPECIAL H1A PATTERN BEING OUTPUT DURING THE LM REP 2.
THE SPH1A2 REGISTER IS USED TO SET THE SPECIAL H1A PATTERN IN THIS REGION.
5. THIS REGION REPRESENTS SPECIAL H1A PATTERN BEING OUTPUT DURING THE LM REP 3.
THE SPH1A3 REGISTER IS USED TO SET THE SPECIAL H1A PATTERN IN THIS REGION.
6. THIS REGION REPRESENTS NORMAL H1A OUTPUTS.
8-BIT
LM COUNTER
CLOCK
SPECIAL
SPHSTARTx
PIXEL
110101
H1A
PROGRAMMING NOTES
1. THIS EXAMPLE SHOWS H1A OUTPUT FOR REGION 3 ABOVE.
IN THIS EXAMPLE: SPH1A1 = 110101.
2. THE SPECIAL H PATTERN STARTING POLARITY CAN BE INDEPENDENTLY SET FOR EACH H OUTPUT
USING THE POL REGISTERS LISTED IN TABLE XVI. NOTE: THE SPECIAL H STARTING POLARITY WILL
OCCUR AT THE START OF SPHSTARTx. (ABOVE: H1APOL = 0)
SPH1A1
H1
H2
Figure 28. Example of Programming the Special H-Output Patterns
132133 13413586815601559
131
HBLKTOG2
HBLKTOG3
823 824825
H1TOG34POL
HBLKTOG4
HBLKTOG1
Figure 29. Example of Horizontal HMASK Masking
HMASK
0
H1MASKPOL
HBLKHBLKHBLK
12 3
H1TOG12POL
4
REV. 0–34–
Page 35
AD9937
SCP0
(FIXED AT LINE 0)
SCP1 [7:0]
SCP4 [7:0]
SCP3 [7:0]
SCP2 [7:0]
CCD REGION 0
CCD REGION 1
CCD REGION 2
CCD REGION 3
CCD REGION 4
REGISTERS LOCATED AT MODE_REG(15)
ARE ACTIVE WHILE
OPERATING IN CCD REGION 0
REGISTERS LOCATED AT MODE_REG(16)
ARE ACTIVE WHILE
OPERATING IN CCD REGION 1
REGISTERS LOCATED AT MODE_REG(17)
ARE ACTIVE WHILE
OPERATING IN CCD REGION 2
REGISTERS LOCATED AT MODE_REG(18)
ARE ACTIVE WHILE
OPERATING IN CCD REGION 3
REGISTERS LOCATED AT MODE_REG(19)
ARE ACTIVE WHILE
OPERATING IN CCD REGION 4
H1
H2
132133 13413523415601559
131
HBLKTOG2
HDLEN
15512
154156233
H1TOG34POL
HDLASTLEN
0
HBLKTOG1
HMASK
0
H1MASKPOL
HBLKHMASKHBLKVERTICAL HMASK
12 3
H1TOG12POL
4
Figure 30. Example of Vertical HMASK Masking with HDLASTLEN > HDLEN with HMASTKSTART = 0 and HMASKSTOP = 1560
VERTICAL TIMING GENERATION
The AD9937 provides a very flexible solution for generating
vertical CCD timing, and can support multiple CCDs and different system architectures. The 4-phase vertical transfer clocks
V1–V4 are used to shift each line of pixels into the horizontal
output register of the CCD. The AD9937 allows these outputs
to be individually programmed into different pulse patterns.
Vertical sequence control registers then organize the individual
CCD REGIONS
Up to five unique CCD regions can be preprogrammed using the
sequence change position registers as described in Table XVII.
The SCPx (x = 0, 1, 2, 3, 4) registers determine when the settings in Mode_Reg(15–19) are active. For example, the SCP1
register activates the registers at Mode_Reg(16) for CCD region 1.
Note that SCP0 is not programmable. The SCP0 position always
starts at Line 0, as shown in Figure 31.
vertical pulses into the desired CCD vertical timing arrangement.
The AD9937 can preprogram three unique sets of vertical transfer
pulses known as VTP0, VTP1, and VTP2. Each VTP set consists
of the four vertical clocks (V1A/B, V2, V3A/B, and V4), as shown
in Figure 32. Once preprogrammed, any one of the three unique
VTP sets can then be selected to be output in any one of the
five CCD regions by using the VTPPATSELx (x = 0, 1, 2, 3, 4)
registers. The VTP_Reg(1–9) registers listed in Table II are used
for generating the VTP pulse sets.
Figure 32 shows an example of programming one VTPx (x = 0, 1, 2)
pulse set. Once a VTP pulse set has been configured, multiple
repetitions of this set can be repeated to create an entire VTP
sequence. This is accomplished by using the VTPREPn
(n = 0, 1, 2, 3, 4) registers where n represents the five CCD regions.
An example of repeating a VTP set is shown in Figure 33.
Register Name*(Bits)TypeRangeDescription
SCP18Mode_Reg(14)0–255 Line PositionsSequence Change Position 1
SCP28Mode_Reg(14)0–255 Line PositionsSequence Change Position 2
SCP38Mode_Reg(14)0–255 Line PositionsSequence Change Position 3
SCP48Mode_Reg(14)0–255 Line PositionsSequence Change Position 4
*There is no SCP0 register. The SCP0 position is always fixed at Line 0.
REV. 0
Table XVII. Sequence Change Positions Registers
LengthRegister
Figure 31. Sequence Change Positions
–35–
Page 36
AD9937
HD COUNTER
12-BIT
V1A/B
1
5
2
V2
V3A/B
V4
78
3
9
4
PROGRAMMING NOTES
*(x = 0, 1, 2) THE x REPRESENTS THE THREE SEPARATE REGISTERS FOR VTP0, VTP1, AND VTP2 SETS. THIS ALSO APPLIES TO THE x
USED IN THE PROGRAMMABLE CLOCK POSITIONS BELOW.
PROGRAMMABLE CLOCK POSITIONS
1. V1POL_x (PROGRAMMABLE AT VTP_REG(x))7. V2TOG1_x (PROGRAMMABLE AT VTP_REG(x))
2. V2POL_x (PROGRAMMABLE AT VTP_REG(x))8. V2TOG2_x (PROGRAMMABLE AT VTP_REG(x))
3. V3POL_x (PROGRAMMABLE AT VTP_REG(x))9. V3TOG1_x (PROGRAMMABLE AT VTP_REG(x))
4. V4POL_x (PROGRAMMABLE AT VTP_REG(x))10. V3TOG2_x (PROGRAMMABLE AT VTP_REG(x))
5. V1TOG1_x (PROGRAMMABLE AT VTP_REG(x))11. V4TOG1_x (PROGRAMMABLE AT VTP_REG(x))
6. V1TOG2_x (PROGRAMMABLE AT VTP_REG(x))12. V4TOG2_x (PROGRAMMABLE AT VTP_REG(x))
1112
VTPLEN_x*
6
10
Figure 32. Example of Programming One VTP Pulse
VTPREPn* = 2
12-BIT
HD COUNTER
V1A/B
V3A/B
75
V2
V4
40
5
*(n = 0, 1, 2, 3, 4) n REPRESENTS THE NUMBER OF PROGRAMMABLE CCD REGIONS. THE NUMBER OF REPETITIONS IN EACH
CCD REGION CAN BE INDEPENDENTLY SET USING THE VTPREP REGISTER FOR THAT REGION.
145
110
180
VTPLEN_x
215
250
285
320
355
390
530
425
495
460
Figure 33. Example of Creating a Sequence of VTP Pulses by Using the VTPREP Register
REV. 0–36–
Page 37
12-BIT
HD COUNTER
V1A/B
V3A/B
AD9937
VTPLEN_0VTPLEN_2
V2
V4
VTP0VTP1VTP2
Figure 34. Example of Three Preprogrammed VTP Pulses
VTPLEN_1
11-BIT
VD COUNTER
12-BIT
HD COUNTER
VD
HD
V1A/B
V3A/B
SCP0
(FIXED AT LINE 0)
001000
V2
V4
SCP1 = 1
002N
REV. 0
VTPPATSEL0 = 1
VREP0 = 1
VTPPATSEL1 = 0
VREP1 = 1
Figure 35. Example of Applying VTP Pulse Sequences to CCD Regions
–37–
Page 38
AD9937
11-BIT
VD COUNTER
12-BIT
HD COUNTER
HD
V1A/B
V3A/B
VD
V2
V4
SCP0
(FIXED AT LINE 0)
SCP1 = 1
001000
002N
VTPPATSEL0 = 1
VREP0 = 1
VTPPATSEL1 = 0
VREP1 = 2
Figure 36. Example of VTP Pulse Sequence with VREP = 2 in CCD Region 1
IT TAKES 500s FOR VCLK TO SETTLE ONCE THE DIG_STBY REGISTER HAS BEEN PROGRAMMED.
3
IT TAKES FOUR VCKM CLOCK CYCLES FROM WHEN OUTCONT IS ASSERTED HIGH UNTIL THE VD, HD, AND DIGITAL OUTPUT DATA IS VALID.
RS, H2(A, B), LM
t
SETTINGS
2
t
= 1.0ms REGARDLESS OF THE VCLK CLOCK FREQUENCY.
PWR
Figure 37. Recommended Power-Up Sequence
POWER-UP FOR MASTER MODE
When the AD9937 is powered up, the following sequence is
recommended. (Refer to Figure 37 for each step.)
1. Turn on power supplies for AD9937.
2. The internal power-on auto-reset circuit will deassert
1.0 ms after VDD settles. (All internal registers are reset to
the default values.)
3. The VCKM clock can be applied as soon as VDD settles.
4. Reset the internal AD9937 registers: write a 0x000000 to
the SW_RESET register (addr 0x00). This will set all internal register values to their default values. (This step is optional
because the internal power-on reset circuit is applied at
power-up.)
5. Write a 1 to the DIG_STBY and AFE_STBY registers
(addr 0x02). This will put the digital and analog circuits into
the normal operating mode.
6. Program all control, system, and mode registers.
7. Write a 1 to the OUTCONT_REG (addr 0x01). This will put
the digital outputs into the normal operating mode. The internal OUTCONT will be asserted high on the rising edge of the
32nd SCK clock when writing to the OUTCONT_REG.
The AD9937 typical circuit connection is shown in Figure 41.
The PCB layout is critical in achieving good image quality from
the AD9937 product. All of the supply pins, particularly the
AVDD, DVDD, TCVDD, RSVDD, HVDD1, and HVDD2
supplies, must be decoupled to ground with good quality high
frequency chip capacitors. The decoupling capacitors should be
located as close as possible to the supply pins, and should have
a very low impedance path to a continuous ground plane. There
should also be a 4.7 µF or larger value bypass capacitor for each
main supply although this is not necessary for each individual pin.
In most applications, it is easier and recommended to share the
same supply for AVDD, DVDD, TCVDD, RSVDD, HVDD1,
and HVDD2, which may be done as long as the individual supply
pins are separately bypassed at each supply pin. A separate 3 V
supply should be used for DRVDD with this supply pin decoupled
to the same ground plane as the rest of the chip. A separate
ground for DRVSS is not recommended.
0.1F
3V
ANALOG SUPPLY
VD, HD
SERIAL
INTERFACE
2
3
The analog bypass pins (REFB, REFT) should also be carefully
decoupled to ground as close as possible to their respective pins.
The analog input (CCDIN) capacitor should also be located
close to the pin.
The H1(A–D), H2(A, B), and RS printed circuit board traces
should be designed to have low inductance to avoid excessive distortion of the signals. Heavier traces are recommended, because of
the large transient current demand on H1(A–D) and H2(A, B) by
the CCD. If possible, physically locate the AD9937 closer to the
CCD to reduce the inductance on these lines. As always, the routing path should be as direct as possible from the AD9937 to the
CCD. Careful trace impedance considerations must also be made
with applications using a flex printed circuit (FPC) connecting the
CCD to the AD9937. FPC trace impedances can be controlled
by applying a solid uniform ground plane under the H1(A–D),
H2(A, B), and RS traces. This helps minimize the amount of
overshoot and ringing on these signals at the CCD inputs.
OFD, LM, V4, TG3B, V3A/B,
8
TG3A, V2, TG1B, V1A/B, TG1A,
TO V-DRIVER
3V
DRIVER
SUPPLY
4.7F
0.1F
10
DATA
OUTPUTS
DATA OUTPUT CLOCK
3V ANALOG SUPPLY
DRVSS
DRVDD
SCK
SLD
SDA
NC
1
PIN 1
NC
2
IDENTIFIER
D0
3
D1
4
D2
5
D3
6
7
8
D4
9
D5
10
D6
11
D7
12
D8
13
D9
14
15 16 17 18 19 20 21 22 23 24
VCLK
HVSS2
HVDD2
0.1F
VD
HD
(Not to Scale)
H2B
H1D
0.1F
DVSS
OFD
5051525354555649
AD9937
TOP VIEW
H1B
HVDD1
TG3B
48 47 46 45 44 43
25 26 27 28
H1C
H2A
H1A
HVSS1
0.1F
TG3A
RS
RSVSS
42
41
40
39
38
37
36
35
34
33
32
31
30
29
RSVDD
V2
V3A/B
V4
LM
DVDD
Figure 41. Typical Circuit Configuration
TG1B
V1A/B
TG1A
REFB
REFT
AVSS
CCDIN
AVDD
VCKM
TCVDD
TCVSS
NC
NC
NC
1.0F
1.0F
0.1F
REF CLOCK INPUT
0.1F
RS
6
H1D, H2B, H1B, H1C, H2A, H1A
3V ANALOG SUPPLY
4.7F
CCD SIGNAL
0.1F
3V ANALOG SUPPLY
REV. 0–42–
Page 43
AD9937
Figures 42 and 43 show the recommended AD9937 supply grouping. Figure 42 shows how the supplies should be tied together when
there are only two available supply sources, whereas Figure 43
shows how the supplies can be tied together when there are three
3V ANALOG
SUPPLY
3V DRIVER
SUPPLY
Figure 42. Recommended Supply Grouping with Two Available Supply Sources
3V ANALOG
SUPPLY 1
3V ANALOG
SUPPLY 2
3V DRIVER
SUPPLY
available supply sources. In either case, all grounds should be
tied together as shown.
Also as shown in Figures 42 and 43 is that the AD9937 DRVDD
supply can be shared with the system ASIC/DSP.
AD9937
AV DD
TCVDD
HVDD1
HVDD2
RSVDD
DVD D
DRVDD
ASIC/DSP
AD9937
AV DD
TCVDD
DVD D
HVDD1
HVDD2
RSVDD
DRVDD
AVSS
TCVSS
HVSS1
HVSS2
RSVSS
DVSS
DRVSS
AVSS
TCVSS
DVSS
HVSS1
HVSS2
RSVSS
DRVSS
ASIC/DSP
Figure 43. Recommended Supply Grouping with Three Available Supply Sources
REV. 0
–43–
Page 44
AD9937
OUTLINE DIMENSIONS
56-Lead Lead Frame Chip Scale Package [LFCSP]
(CP-56)
Dimensions shown in millimeters
1.00
0.85
0.80
12 MAX
SEATING
PLANE
BSC SQ
PIN 1
INDICATOR
TOP
VIEW
8.00
0.60 MAX
7.75
BSC SQ
0.50
0.40
0.30
0.80 MAX
0.65 TYP
0.50 BSC
COMPLIANT TO JEDEC STANDARDS MO-220-VLLD-2
0.20 REF
0.05 MAX
0.02 NOM
COPLANARITY
0.08
43
42
29
28
0.60 MAX
BOTTOM
VIEW
6.50
REF
0.30
0.23
0.18
PIN 1
INDICATOR
56
1
6.25
SQ
6.10
5.95
14
15
0.25 MIN
C03556–0–5/03(0)
–44–
REV. 0
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