TI TC237B

TC237B
680- × 500-PIXEL CCD IMAGE SENSOR
SOCS063 – APRIL 2001
D High Resolution, 1/3-in Solid-State Image
D
D
D
D
D
D
D
D
D
Sensor for NTSC Black and White
Applications
340,000 Pixels per Field
Frame Memory
658 (H) × 496 (V) Active Elements in Image
Sensing Area Compatible With Electronic
Centering
Multimode Readout Capability
– Progressive Scan
– Interlaced Scan
– Dual-Line Readout
– Image Area Line Summing
– Smear Subtraction
Fast Single-Pulse Clear Capability
Continuous Electronic Exposure Control
From 1/60 – 1/50,000 s
7.4-µm Square Pixels
Advanced Lateral Overflow Drain
Antiblooming
Low Dark Current
DUAL-IN-LINE PACKAGE
(TOP VIEW)
D
D
D
D
D
ODB 1
12 IAG1
IAG2 2
11 SAG
SUB 3
10 SAG
ADB 4
9 SUB
OUT1 5
8 SRG
OUT2 6
7 RST
High Photoresponse Uniformity
High Dynamic Range
High Sensitivity
High Blue Response
Solid-State Reliability With No Image
Burn-In, Residual Imaging, Image
Distortion, Image Lag, or
Microphonics
description
The TC237B is a frame-transfer, charge-coupled device (CCD) image sensor designed for use in single-chip
black and white National Television Standards Committee (NTSC) TV, computer, and special-purpose
applications that require low cost and small size.
The image-sensing area of the TC237B device is configured into 500 lines with 680 elements in each line.
Twenty-two elements are provided in each line for dark reference. The antiblooming feature of the sensor is
based on an advanced lateral overflow drain concept. The sensor can be operated in a true interlace mode as
a 658(H) × 496(V) sensor with a low dark current. An important feature of the TC237B high-resolution sensor
is the ability to capture a full 340,000 pixels per field. The image sensor also provides high-speed image transfer
capability and a continuous electronic exposure control without the loss of sensitivity and resolution inherent
in other technologies. Charge voltage is converted to signal voltage at 13 µV per electron by a high-performance
structure with a reset and a voltage-reference generator. The signal is further buffered by a low-noise,
two-stage, source-follower amplifier to provide high-output drive capability.
The TC237B sensor is built using TI-proprietary advanced virtual-phase (AVP) technology, which provides
devices with high blue response, low dark current, high photoresponse uniformity, and single-phase clocking.
The TC237B sensor is characterized for operation from – 10°C to 45°C.
This MOS device contains limited built-in gate protection. During storage or handling, the device leads should be shorted together
or the device should be placed in conductive foam. In a circuit, unused inputs should always be connected to VSS. Under no
circumstances should pin voltages exceed absolute maximum ratings. Avoid shorting OUT to VSS during operation to prevent
damage to the amplifier. The device can also be damaged if the output terminals are reverse-biased and an excessive current is
allowed to flow. Specific guidelines for handling devices of this type are contained in the publication Guidelines for Handling
Electrostatic-Discharge-Sensitive (ESDS) Devices and Assemblies available from Texas Instruments.
Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of
Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.
TI is a trademark of Texas Instruments.
All other trademarks are the property of their respective owners.
Copyright  2001, Texas Instruments Incorporated
PRODUCTION DATA information is current as of publication date.
Products conform to specifications per the terms of Texas Instruments
standard warranty. Production processing does not necessarily include
testing of all parameters.
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1
TC237B
680- × 500-PIXEL CCD IMAGE SENSOR
SOCS063 – APRIL 2001
functional block diagram
SUB
ODB
IAG2
3
1
Image Area With
Blooming Protection
12
Dark Reference Elements
11
2
Storage Area
ADB
OUT2
IAG1
4
10
9
Amplifiers
6
8
SAG
SAG
SUB
SRG
4 Dummy Elements
OUT1
5
7
Clearing Drain
sensor topology diagram
22 Dark-Reference Pixels
658 Active Pixels
Two-Phase Image-Sensing Area
496 Lines
4 Dark Lines
500 Lines
4
22
658 Active Pixels
Optical Black
(OPB)
Dummy Pixels
4
2
Single-Phase Storage Area
22
658 Active Pixels
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RST
TC237B
680- × 500-PIXEL CCD IMAGE SENSOR
SOCS063 – APRIL 2001
Terminal Functions
TERMINAL
NAME
NO.
I/O
DESCRIPTION
ADB
4
I
Supply voltage for amplifier drain bias
IAG1
12
I
Image area gate 1
IAG2
2
I
Image area gate 2
ODB
1
I
Supply voltage for drain antiblooming bias
OUT1
5
O
Output signal 1
OUT2
6
O
Output signal 2
RST
7
I
Reset gate
SAG
10, 11
I
Storage area gate
SRG
8
I
Serial register gate
SUB
3, 9
Substrate
detailed description
The TC237B CCD image sensor consists of four basic functional blocks: the image-sensing area, the image
storage area, the serial register gates, and the low-noise signal processing amplifier block with charge detection
nodes and independent resets. The location of each of these blocks is identified in the functional block diagram.
image-sensing and image storage areas
Figure 1 and Figure 2 show cross sections with potential well diagrams and top views of the image-sensing and
storage area elements. As light enters the silicon in the image-sensing area, electrons are generated and
collected in the wells of the sensing elements. Blooming protection is provided by applying a dc bias to the
overflow drain bias pin. To clear the image before beginning a new integration time (for implementation of
electronic fixed shutter or electronic auto-iris), apply a pulse of at least 1 µs to the overflow drain bias. After
integration is complete, charge voltage is transferred into the storage area. The transfer timing depends on
whether the readout mode is interlace or progressive scan. If the progressive-scan readout mode is selected,
the readout may be performed by using one serial register or at high speed by using both serial registers (see
Figure 3 through Figure 5). A line-summing operation, which is useful in off-chip smear subtraction, can be
implemented before the parallel transfer (see Figure 6).
Twenty-two columns at the left edge of the image-sensing area are shielded from incident light; these elements
provide the dark reference used in subsequent video-processing circuits to restore the video black level. In
addition, four dark lines between the image-sensing and the image storage area prevent charge leakage from
the image-sensing area into the image storage area.
advanced lateral overflow drain
The advanced lateral overflow drain structure is shared by two neighboring pixels and provides several unique
features in the sensor. By varying the dc bias of the drain pin, you can control the blooming protection level and
trade it for the well capacity.
To clear charge voltages in the image area, apply a 10-V pulse for a minimum duration of 1 µs above the nominal
dc bias level. This feature permits a precise control of the integration time on a frame-by-frame basis. The
single-pulse clear capability also reduces smear by eliminating accumulated charge from the pixels before the
start of the integration (single-sided smear).
Application of a negative 1-V pulse to the ODB signal during the parallel transfer is recommended to prevent
slight column-to-column pixel well capacity variations in some artifacts.
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TC237B
680- × 500-PIXEL CCD IMAGE SENSOR
SOCS063 – APRIL 2001
7.4 µm
Clocked Barrier
3.8 µm
Clocked Well
Virtual Barrier
3.6 µm
Antiblooming
Device
Virtual Well
Channel Stops
Including Metal Bus Lines
Clocked Gate
1.6 µm
1.6 µm
Figure 1. Image-Area Pixel Structure
7.4 µm
Clocked Barrier
3.5 µm
Clocked Well
Virtual Barrier
3.5 µm
Virtual Well
Channel Stops
Including Metal Bus Lines
Clocked Gate
1.6 µm
1.6 µm
Figure 2. Storage-Area Pixel Structure
4
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TC237B
680- × 500-PIXEL CCD IMAGE SENSOR
SOCS063 – APRIL 2001
Clear
Integrate
Transfer to Memory
Readout
1 µs Minimum
ODB
†
IAG1, 2
250 Cycles
†
SAG
684 Pulses
†
‡
SRG
684 Pulses
RST
Expanded Section of
Parallel Transfer
IAG1, 2
SAG
SRG
Figure 3. Interlace Timing
† The number of parallel-transfer pulses is field dependent. Field 1 has 500 pulses of IAG1, IAG2, SAG, and SRG with appropriate phasing. Field 2
has 501 pulses.
‡ The readout is from register 2.
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5
TC237B
680- × 500-PIXEL CCD IMAGE SENSOR
SOCS063 – APRIL 2001
Clear
Integrate
Transfer to Memory
Readout
1 µs Minimum
ODB
500 Pulses
IAG1, 2
500 Pulses
500 Cycles
SAG
500 Pulses
684 Pulses†
SRG
684 Pulses
RST
Expanded Section of
Parallel Transfer
IAG1, 2
SAG
SRG
† The readout is from register 2.
Figure 4. Progressive-Scan Timing With Single Register Readout
6
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TC237B
680- × 500-PIXEL CCD IMAGE SENSOR
SOCS063 – APRIL 2001
Clear
Integrate
Transfer to Memory
Readout
1 µs Minimum
ODB
500 Pulses
IAG1, 2
250 Cycles
500 Pulses
SAG
684 Pulses
500 Pulses
SRG
684 Pulses
RST
Expanded Section of
Parallel Transfer
IAG1, 2
SAG
SRG
Figure 5. Progressive-Scan Timing With Dual-Register Readout
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TC237B
680- × 500-PIXEL CCD IMAGE SENSOR
SOCS063 – APRIL 2001
Clear
Integrate
Line
Sum
Transfer to Memory
Readout
1 µs Minimum
ODB
†
¶
IAG1
‡
¶
IAG2
250 Cycles
¶
SAG
¶
§
684 Pulses
SRG
684 Pulses
RST
Expanded Section of
Parallel Transfer
IAG1, 2
SAG
SRG
Figure 6. Line-Summing Timing
† This pulse occurs only during field 1.
‡ This pulse occurs only during field 2.
§ While readout is from register 2, register 1 can be read out for off-chip smear subtraction.
¶ The number of parallel transfer pulses if field dependent. Field 1 has 500 pulses, and field 2 has 501 pulses.
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TC237B
680- × 500-PIXEL CCD IMAGE SENSOR
SOCS063 – APRIL 2001
serial registers
The storage area gate and serial gate(s) are used to transfer charge line-by-line from the storage area into the
serial register(s). Depending on the readout mode, one or both serial registers are used. If both are used, the
registers are read out in parallel.
readout and video processing
After transfer into the serial register(s), the pixels are clocked out and sensed by a charge detection node. The
node must be reset to a reference level before the next pixel is placed onto it. The timing for the serial-register
readout, which includes the external pixel clamp and sample-and-hold signals needed to implement correlated
double sampling, is shown in Figure 7. As charge is transferred onto the detection node, the potential of the node
changes in proportion to the amount of the charge received. The change is sensed by an MOS transistor; after
proper buffering, the signal is supplied to the output terminal of the image sensor. Figure 8 shows the circuit
diagram of the charge detection node and output amplifier. The detection nodes and amplifiers are placed a
short distance from the edge of the storage area; therefore, each serial register contains 4 dummy elements
that are used to span the distance between the serial registers and the amplifiers.
SRG
RST
OUT
S/H
PCMP
Figure 7. Serial Readout and Video-Processing Timing
VREF
QR
ADB
Q1
Q2
Reset
CCD Channel
VOUT
Figure 8. Output Amplifier and Charge Detection Node
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TC237B
680- × 500-PIXEL CCD IMAGE SENSOR
SOCS063 – APRIL 2001
absolute maximum ratings over operating free-air temperature range (unless otherwise noted)†
Supply voltage range, ADB (see Note 1) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . SUB to SUB + 15 V
Supply voltage range, ODB . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . SUB to SUB + 21 V
Input voltage range, VI: IAG1, IAG2, SAG, SRG . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0 V to 15 V
Operating free-air temperature range, TA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . – 10°C to 45°C
Storage temperature range, Tstg . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . – 30°C to 85°C
Operating case temperature range, TC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . – 10°C to 55°C
† Stresses beyond those listed under “absolute maximum ratings” may cause permanent damage to the device. These are stress ratings only, and
functional operation of the device at these or any other conditions beyond those indicated under “recommended operating conditions” is not
implied. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability.
NOTE 1: All voltage values are with respect to SUB.
recommended operating conditions
ADB
Supply voltage,
voltage VCC
ODB
MIN
NOM
21
22
23
For antiblooming control
15.5
16
16.5
For clearing
25.5
26
26.5
For transfer
14.5
15
15.5
Substrate bias voltage
10
High level
IAG1 IAG2
IAG1,
SAG
Clock frequency, fclock
Load capacitance
11.5
12
11.5
12
V
12.5
V
12.5
0
12.5
SAG
12.5
SRG, RST
12.5
OUT1, OUT2
– 10
• DALLAS, TEXAS 75265
V
12.5
0
IAG1, IAG2
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UNIT
0
Low level
Operating free-air temperature, TA
10
12
Low level
High level
SRG RST
SRG,
11.5
Low level
High level
Input voltage,
voltage VI
MAX
MHz
6
pF
45
°C
TC237B
680- × 500-PIXEL CCD IMAGE SENSOR
SOCS063 – APRIL 2001
electrical characteristics over recommended ranges of supply voltage and operating free-air
temperature (unless otherwise noted)
PARAMETER
Dynamic range (see Note 2)
MIN
TYP†
With CDS‡§
64
Without CDS‡§
58
Charge conversion factor
MAX
59
0.9999
Signal response delay time, τ (see Note 4)
0.99995
1
12.5
Gamma (see Note 5)
dB
µV/e
13
Charge transfer efficiency (see Note 3)
UNIT
ns
1
Output resistance
Amplifier noise equivalent signal
Rejection ratio
300
400
500
With CDS‡
15
18
21
Without CDS‡
30
36
42
ADB (see Note 6)
20
SRG (see Note 7)
45
ODB (see Note 8)
25
Supply current
5
IAG1, IAG2
Input capacitance,
capacitance Ci
Ω
electrons
dB
10
mA
2000
SRG
70
RST
10
pF
SAG
4000
† All typical values are at TA = 25°C.
‡ CDS = Correlated double sampling, a signal-processing technique that improves noise performance by subtraction of reset noise.
§ Performance depends on the particular implementation of the CDS technique and on the selected filter bandwidth that precedes sampling.
NOTES: 2. Dynamic range is – 20 times the logarithm of the mean-noise signal divided by the saturation output signal.
3. Charge transfer efficiency is one minus the charge loss per transfer in the output register. The test is performed in the dark using
an electrical input signal.
4. Signal response delay time is the time between the falling edge of the SRG pulse and the output signal valid state.
5. Gamma (γ) is the value of the exponent in the equation below for two points on the linear portion of the transfer function curve (this
value represents points near saturation).
g
Exposure (2)
Output signal (2)
+ Output signal (1)
Exposure (1)
ǒ
Ǔ
ǒ
Ǔ
6. ADB rejection ratio is – 20 times the logarithm of the ac amplitude at the output divided by the ac amplitude at ADB.
7. SRG rejection ratio is – 20 times the logarithm of the ac amplitude at the output divided by the ac amplitude at SRG.
8. ODB rejection ratio is – 20 times the logarithm of the ac amplitude at the output divided by the ac amplitude at ODB.
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TC237B
680- × 500-PIXEL CCD IMAGE SENSOR
SOCS063 – APRIL 2001
optical characteristics, TA = 40°C (unless otherwise noted)
PARAMETER
MIN
No IR filter
Sensitivity (see Note 9)
TYP
MAX
UNIT
256
With IR filter
mV/lux
32
Saturation signal, Vsat (see Note 10)
Antiblooming disabled
Maximum usable signal, Vuse
Antiblooming enabled
TA =45°C
TA =45°C
320
mV
120
mV
Blooming overload ratio (see Note 11)
500
Image area well capacity
22K
30K
38K
electrons
dB
nA/cm2
Smear (see Note 12)
See Note 13
– 78
Dark current
TA = 21°C
TA = 45°C
0.05
1
mV
TA = 45°C
TA = 45°C
0.5
mV
0.5
mV
TA = 45°C
TA = 45°C
10
mV
Dark signal
Dark-signal uniformity
Dark-signal shading
Dark
Spurious nonuniformity
Illuminated, F#8
Column uniformity
Electronic shutter capability
1/50,000
1/60
15
%
0.5
mV
s
NOTES: 9. Theoretical value
10. Saturation is the condition in which further increase in exposure does not lead to further increase in output signal.
11. Blooming is the condition in which charge is induced in an element by light incident on another element. Blooming-overload ratio
is the ratio of blooming exposure to saturation exposure.
12. Smear is a measure of the error introduced by transferring charge through an illuminated pixel in shutterless operation. It is
equivalent to the ratio of the single-pixel transfer time to the exposure time using an illuminated section that is 1/10 of the image-area
vertical height with recommended clock frequencies.
13. The exposure time is 16.67 ms, the fast-dump clocking rate during vertical transfer is 12.5 MHz, and the illuminated section is 1/10
the height of the image section.
TYPICAL CHARACTERISTICS
TC237B Spectral Responsivity
16.6 ms T-int (diagonal lines represent QE)
0.4
60%
40%
0.2
DATA
20%
Responsivity [A/W]
0
400
500
600
700
800
900
1000
1100
Wavelength [nm]
Figure 9. Spectral Characteristics of the TC237B CCD Sensor
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TC237B
680- × 500-PIXEL CCD IMAGE SENSOR
SOCS063 – APRIL 2001
APPLICATION INFORMATION
+2 V
TC237
560
Ω
10 kΩ
4.7 Ω
RST_CLK
CCD_SRG
0.1 µF
SRG_CLK
A1
A2
A3
A4
G
2.2 kΩ
Y1
Y2
Y3
Y4
IAG1
ODB
SAG
IAG2
SAG
SUB
SUB
ADB
SRG OUT 1
RST OUT 2
0.1 µF
4.7 Ω
10 Ω
10 Ω
+12 V
CCD_OUT1
CCD_OUT2
74ACT240NS
560
–10 Ω
v
10 kΩ
+5 V
+2 V
560
Ω
3.9
kΩ
10 kΩ
HN1A01F
1.2
kΩ
CCD_RST
0.1 µF
2.2 kΩ
0.1 µF
4.7 Ω
+2 V
10 Ω
10 Ω
EL7202C
CCD_IAG
1
CCD_IAG2
1.8
kΩ
1.8
kΩ
NC
NC
OUTA INA
V+
GND
OUTB INB
560
–10 Ω
10 kΩ
HN1A01F
E1 E2
B1
B2
C1 C2
v
1.8
kΩ
2.7
kΩ
1.8
kΩ
2 kΩ
CCD_ODB
HN1A01F
10 Ω
1.5
kΩ
E1 E2
B1
B2
C1 C2
5.2
kΩ
SAG_CLK
3.3 kΩ
EL7202C
3.3 kΩ
CCD_SAG
NC
1.8
kΩ
NC
OUTA INA
ODB
Driver
V+
GND
OUTB INB
NOTES:
IAG2_CLK
–10 V
+15 V
ODB_CLK
IAG1_CLK
E1 E2
B1
B2
C1 C2
4.7 Ω
Serial
Driver
1.8
kΩ
Parallel
Driver
A. Support circuits
DEVICE
APPLICATION
FUNCTION
EL7202C
74ACT240NS
Parallel driver
Serial pre-driver
Driver for IAG1, IAG2,SAG
Driver for SRG, RST
B. Clock, DC voltages
Clock
SRG_CLK, RST_CLK, ODB_CLK, IAG1_CLK,
IAG2_CLK, SAG_CLK
DC
+15 V, +12 V, +5 V, +2 V, 0 V, (Ground), –10 V
TTL level
Figure 10. Typical Application Circuit Diagram
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TC237B
680- × 500-PIXEL CCD IMAGE SENSOR
SOCS063 – APRIL 2001
MECHANICAL DATA
The package for the TC237B consists of a ceramic base, a glass window, and a 12-lead frame. The glass window
is sealed to the package by an epoxy adhesive. The package leads are configured in a dual-in-line organization and
fit into mounting holes with 1,78 mm center-to-center spacings.
TC237 (12 pin)
Index
Mark
4,45
4,15
Optical
Center
Package
Center
5,94
5,64
ÎÎÎÎÎÎ
ÎÎÎÎÎÎ
ÎÎÎÎÎÎ
ÎÎÎÎÎÎ
ÎÎÎÎÎÎ
ÎÎÎÎÎÎ
12,40
12,00
11,85
10,75
11,50
11,10
11,05
10,95
1,78
0,76
ÎÎ
ÎÎ
ÎÎ
ÎÎ
ÎÎ
ÎÎ
ÎÎ
1,91
1,65
0,51
0,41
3,65
3,35
3,30
2,80
Focus Plane
2,08
1,48
0,33
0,17
4,00
3,40
11,68
11,18
ALL LINEAR DIMENSIONS ARE IN MILLIMETERS
14
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Copyright  2001, Texas Instruments Incorporated