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DHigh-Resolution, Solid State Image Sensor
for B/W Video and Computer Applications
D11-mm Image-Area Diagonal Compatible
with 2/3” Vidicon Optics
D754(H)×484(V) Active Elements in
Image-Sensing Area
DLateral Overflow Drain Antiblooming
DElectronic Exposure Control
DInterlace or Progressive Scan Readout
DLine Summing and Pixel Summing Modes
DLow Dark Current
DDynamic Range Larger than 64 dB
DHigh Sensitivity
DHigh Blue Response Including DUV
DSingle Phase Clocking
DSolid State Reliability With No Image
Burn-In, Residual Imaging, Image
Distortion, Image Lag, or Microphonics
description
The Texas Instruments TC341 sensor is a high-performance frame-transfer charge-coupled device (CCD)
image sensor. It is designed for use in B/W video and computer camera applications. The device is intended
to replace the 2/3-inch vidicon tube in applications requiring small size, high reliability, and lower cost.
The image-sensing area of the TC341 sensor is configured into 488 lines with 780 elements in each line.
Twenty-six elements are provided in each line for a dark reference. The blooming protection of the sensor is
based on an advanced lateral overflow drain (ALOD). The antiblooming function is activated when a suitable
dc bias is applied to the antiblooming drain pin. With this type of blooming protection it is also possible to clear
the image area of all charge. This is accomplished by supplying a single 10 V pulse for a minimum of 1 µs to
the overflow drain pin.
The sensor is designed to operate in interlace as well in progressive scan modes. The interlace mode of
operation can be achieved in two ways: by skipping odd or even lines in corresponding image fields or by a
suitable line summing. The line summing provides higher sensitivity, because all collected charge is used. The
line skipping provides somewhat higher vertical resolution, but with a penalty of lower sensitivity. The
progressive scan mode sacrifices neither sensitivity nor resolution.
A standard gated floating-diffusion charge detection node structure converts charge into a signal voltage. For
higher accuracy and stability, this structure is reset to an on-chip automatic potential-tracking voltage reference.
The reset gate has a separate external pin, which allows implementing pixel summing by skipping the detection
node reset pulses. A low-noise, two-stage, source-follower amplifier buffers the output and provides high
output-driving capability. The TC341 sensor is built using TI-proprietary virtual-phase technology, which
provides devices with high blue response, low dark current, high photoresponse uniformity, and a single-phase
clocking.
The TC241 sensor is characterized for operation from –10°C to 45°C.
Copyright 2002, Texas Instruments Incorporated
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.
1
2
3
4
5
9
17
16
15
14
13
12
ODB
IAG
SAG
GND
6
7
8
10
11
GND
SAG
GND
VOUT
VDD
CDB
NC
18
19
20
21
22
NC
RSG
TRG
SRG
NC
GND
GND
GND
IAG
IDB
GND
DUAL-IN-LINE PACKAGE
(TOP VIEW)
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functional block diagram
ODB
IAG IAG
SAG
Dark Reference Pixels
Image Sensing Area
with Blooming Protection
Image Storage Area
Serial Readout Register
Output
Amplifier
ÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎ
ÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎ
GND
GND
IDB
GND
GND
SAG
Vout
VDD
CDB
NC
Input
Diode
NC
Charge Clearing
Drain
Transfer Gate
RSG
TRG
SRG
NC
GND
GND
GND
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sensor topology diagram
Dark Reference Pixels
Image Sensing Area
with Blooming Protection
Image Storage Area
26 754 Active Pixels
Optical Black Pixels (OPB)
26 Dark
Reference
Pixels 754 Active Pixels
484 Active Lines
488 Lines
Four Dark
Isolation Lines
One Dummy Pixel
Dummy Pixels
790 Pixels
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Terminal Functions
TERMINAL
I/O
DESCRIPTION
NAME NO. I/O DESCRIPTION
CDB 10 I Charge clearing drain bias
GND 1, 4, 7, 17,
18, 19, 22 Chip substrate (SUB)
IAG 3, 20 IImage area gate
IDB 21 I Input diode bias
NC 11, 12, 16 –No connection
ODB 2 I Charge overflow drain bias
RSG 13 I Detection node reset gate
SAG 5, 6 IStorage area gate
SRG 15 I Serial register gate
TRG 14 I Transfer gate
VDD 9 I Amplifier drain bias
VOUT 8 O Sensor output
detailed description
The TC341 sensor consists of four basic functional blocks: the image-sensing area, the image storage area,
the serial register, and the charge detection amplifier. The location of each of these blocks is identified in the
functional block diagram.
image sensing and storage areas
Figure 1 shows a cross-section with potential-well diagrams and Figure 2 shows a top view of pixels in the
image-sensing and storage areas. As light enters silicon in the image-sensing area, electrons are generated
and collected in potential wells of the pixels. Applying a suitable dc bias to the antiblooming drain provides
blooming protection. The amount of charge that exceeds a specified level, determined by the ODB bias, is
drained away from the pixels. If it is necessary to remove all previously accumulated charge from the wells, a
short positive pulse must be applied to the drain. This marks the beginning of the new integration period. After
the integration cycle is completed, charge is quickly transferred into the memory where it waits for readout. The
lines can be read out from the memory in a sequential order to implement progressive scan, or two lines can
be summed together in the serial register to implement a pseudo-interlace scan. The true interlace scan is
implemented by skipping odd or even lines, depending on the readout field, and dumping the unwanted charge
into the clearing drain that is located next to the serial register.
Twenty-six columns at the left edge of the image-sensing area are shielded from incident light. These pixels
provide the dark reference that is used in subsequent video-processing circuits to restore the video black level.
An additional four dark lines, located between the image-sensing area and the image storage area, were added
for isolation.
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+ + + + + + + + + + + + + + + + + + + + + + +
+ + + + + + + + + + + + + +
n—Buried Channel
p—Substrate
p+
Virtual Phase Gate
X
Ø
Pixel Cross Section
Channel Potential
for High Clock Bias
Charge
Transfer
IAG
Polysilicon Gate
+ + + + + + + + + + + + + + + + + +
Virtual
Well
Clocked
Well
Charge
Transfer
Channel Potential
for Low Clock Bias
ÏÏÏÏÏÏÏÏÏÏ
ÏÏÏÏÏÏÏÏÏÏ
Figure 1. Image Area and Storage Area Pixel Cross Section with Potential Diagram
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Antiblooming
Drain
Channel Stops
IAG
SAG
Image Area Pixel
Storage Area Pixel
11.5 µm
13.5 µm
11.5 µm
Figure 2. Image Area and Storage Area Pixel Topologies
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advanced lateral overflow drain
The advanced overflow drain structure is shared by two neighboring pixels in each line. Varying the dc bias of
the antiblooming drain controls the blooming protection level and trades it for well capacity. Applying a pulse
(approximately 10 V above the nominal level for a minimum of 1 µs) to the drain removes all charge from the
pixels. This feature permits a precise control of the integration time on a frame-by-frame basis. The single-pulse
clearing capability also reduces smear by eliminating accumulated charge in the pixels before the start of the
integration period (single-sided smear). The application of a negative 1-V pulse to the antiblooming drain during
the parallel transfer is recommended. This pulse prevents creation of undesirable artifacts caused by the
on-chip crosstalk between the image area gate clock lines and the antiblooming drain bias lines.
serial register
The serial register is used to transport charge stored in the pixels of the memory to the output amplifier. The
register well capacity is designed to hold two complete lines of data. This allows implementation of pixel
summing in the vertical direction (line summing) and thus also implementation of pseudo-interlace. This is
accomplished by summing together lines 1+2, 3+4, … in one field and lines 2+3, 4+5, … in the other. The true
interlace is obtained by skipping appropriate lines in each field and dumping unwanted charge into a clearing
drain. The clearing drain is located next to the serial register and charge is directed to it via a special charge
transfer gate (TRG).
charge detection node
The last element of the charge readout chain is the charge detection node. The charge detection used in this
device is based on a floating diffusion (FD) concept. The n+ FD node serves as a capacitor that is first reset
to a suitable reference voltage. Charge from the serial register pixel is then transferred on the node. This causes
a change in the potential of FD, and a gate of the first stage source follower transistor connected to it senses
this change. The output signal from the first stage is further buf fered by another source follower stage to provide
necessary driving capability for the off-chip circuits.
The reset gate of the detection node reset transistor is connected to its own pin. This allows more flexibility in
operating the sensor. By skipping the reset pulses, charge from several pixels can be summed together. This
feature also allows an easy implementation of correlated double sampling (CDS) that is used to minimize the
undesirable effect of reset (kTC) noise.
The detection node is reset to a voltage reference that is generated internally on-chip and tracks the process
induced potential variations. This improves the accuracy and stability of the device operation.
special feature
The sensor is provided with a charge input structure located at the upper right-hand corner of the image-sensing
array. Charge input may be useful for a variety of applications, but its main purpose here is electrical testing of
the sensor during manufacturing.
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absolute maximum ratings over operating free-air temperature (unless otherwise noted)†
Supply voltage range, VSS: ADB, CDB, IDB (see Note1) SUB to SUB + 15 V. . . . . . . . . . . . . . . . . . . . . . . . . . .
Supply voltage range, VSS: ODB SUB to SUB + 20 V. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Input voltage range, VI: IAG, SAG, SRG, RSG SUB – 15 V to SUB + 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 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 , an d
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 (GND).
recommended operating conditions
MIN NOM MAX UNIT
Substrate bias (GND), Vss 0
ADB 11.5 12 12.5
CDB 11.5 12 12.5
V
Supply voltages, VDD For blooming control 5 8 V
Su ly
voltages,
VDD
ODB†For clearing
ODB†
For transfer
IAG SAG
High 1.5 2 2.5
IAG, SAG Low –10.5 –10 –9.5
SRG
High 1.5 2 2.5
Inp t oltages V ‡
SRG Low –10.5 –10 –9.5
V
Input voltages, VI
‡
RSG
High 1.5 2 2.5 V
RSG Low
TRG
High 1.5 2 2.5
TRG Low
IAG 8
SAG 8
Clock frequency, fck SRG 14.7 MHz
Clock
frequency,
fck
RSG 14.7
MHz
TRG 8
Load capacitance Cout 3 pF
Operating free-air temperature, TA–10 45 °C
†Fine tuning of ODB voltage is required to achieve an optimum antiblooming performance.
‡Fine tuning of gate clock input voltages is required to obtain the best charge transfer performance.
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electrical characteristics over recommended operating ranges of supply voltage at operating
free-air temperature (unless otherwise noted)
MIN TYP‡MAX UNIT
Charge conversion factor 6µV/e
τSignal-response delay time (Note 2) 6 10 ns
Output resistance 500 Ω
Output dc level 3.6 5.5 V
Saturation voltage for progressive scan 240 mV
Saturation voltage for interlace scan by line summing 480 mV
Amplifier noise-equivalent signal without CDS† (Note 3) 50 e
Amplifier noise-equivalent signal with CDS† (Note 3) 35 e
Output signal dynamic range without CDS†64 dB
Output signal dynamic range with CDS†67 dB
Response linearity (Note 4) 1
Charge-transfer efficiency parallel register 0.9999 1
Charge-transfer efficiency serial register 0.9999 1
Supply current mA
IAG
SAG
CI
Inp t capacitances
SRG
pF
CI Input capacitances RSG pF
TRG
ODB
ADB
SRG high
P lse amplit de rejection ratio
SRG low
dB
Pulse amplitude rejection ratio RSG high (Note 5) dB
RSG low (Note 5)
ODB high (Note 6)
†All typical values are at TA = 25°C.
‡CDS is a signal processing technique that improves performance by minimizing undesirable effects of reset noise.
NOTES: 2. The signal delay time is measured from the falling edge of the reset pulse (SRG) to 90% of valid signal.
3. The noise measurement is performed at 14.0 MHz. The value shown in the table is RMS value.
4. The response linearity is measured as a deviation from the straight line of the signal transfer curve (voltage output versus light input)
at the output saturation point.
5. This level affects only the reset feed through.
6. The charge clearing pulse applied to ODB during the charge readout may cause a slight feed through in the output. To avoid this
problem it is recommended to apply the charge clearing pulse only during the horizontal blanking times.
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optical characteristics, TA = 40°C (unless otherwise noted)
MIN TYP MAX UNIT
Sensitivity (Note 7) No IR filter 413 mV/Lx
With IR filter 51
VOFF Zero input offset (Note 8) 0 100 200 mV
Blooming overload ratio (Note 9) 500:1
Image area well capacity with antiblooming off 70k 80k 00k
Image area well capacity with antiblooming on 35k 40k 45k
Smear (Note 10) –75 dB
Dark current (Note 11) TA = 21°C 0.1 nA/cm2
Dark signal (Note 12) TA = 21°C 0.06 mV
Dark-signal uniformity (Note 13) TA = 21°C 0.03 mV
Dark-signal shading (Note 14) TA = 21°C 0.03 mV
Spurious nonuniformity Dark (Note 15) TA = 21°C 3.5 mV
Illuminated lens F#8 TA = 21°C 15 %
Column uniformity (Note 16) TA = 21°C 0.3 mV
Electronic-shutter capability 1/1000 1/30 sec
NOTES: 7. Light source temperature is 2856°K. The IR filter used is CM500 1mm thick. Integration time is 1/30 sec.
8. This is a signal pedestal measured from the output level after reset to the output level after the SRG negative transition without any
light input into the sensor.
9. Blooming is the condition in which charge induced by light in one element spills over to the neighboring elements.
10. Smear is the measure of error signal introduced into the pixels by transferring them through the illuminated region into the memory.
The illuminated region is 1/10 of the image area height. The value in the table is obtained for the integration time of 33.33 ms and
8 MHz vertical clock transfer frequency.
11. Dark current depends on temperature and approximately doubles every 8°C.
12. Dark signal is actual device output measured in dark.
13. Dark signal uniformity is the sigma of difference of two neighboring pixels taken from all the image area pixels.
14. Dark signal shading is the difference between maximum and minimum of 5 pixel median taken anywhere in the array.
15. Spurious non-uniformity is the signal of no more than three neighboring pixels that exceeds or is less than average.
16. Column uniformity is obtain by summing all the lines in the array, finding the maximum of the difference of two neighboring columns
anywhere in the array, and dividing the result by number of lines.
pixel defect specifications, integration time = 1/60 sec, temperature = 40°C
DEVICE PART
NUMBER DEVICE IN DARK DEVICE ILLUMINATED TOTAL
DEFECT
COUNT
DEFECT COUNT
NUMBER WS BS WS/BS DEFECT
COUNT
NUMBER WS SIGNAL OUTPUT
LEVEL
AREA AREA AREA AREA
A B A B A B A B
TC341-20 > 3.5 mV 0 0 0 0 0 0 > 5% 0 0 50 mV
+/– 10 mV 0
TC341-30 2.5~3.5 mV 2 5 2 5 2 2 5~7.5% 2 5 12
> 3.5 mV 0 0 0 0 0 0 > 7.5% 0 0
TC341-40 3.5~7 mV 3 7 3 7 3 7 7.5~15% 3 7 15
> 7 mV 0 0 0 0 0 0 > 15% 0 0
17. See Figure 3 for definitions of area A and area B.
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233 Lines
360 Pixels
AB
20 Pixels 15 Pixels
14 Lines
22 Lines
Figure 3. Image Sensing Area Map
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timing requirements
Clear Integrate Transfer to Memory Readout
ODB
IAG
SAG
SRG
IAG
SAG SRG
RSG
Expanded Section of Parallel Transfer:
487 Pulses Even Field, 488 Pulses Odd Field
Expanded Section of Serial Transfer
244 Cycles
790 Pulses Line 1790 Pulses Line 244
Pulse Position
Determines Exposure
RSG
TRG
SRG
TRG 140 ns > 10 ns
70 ns
35 ns
> 10 ns > 15 ns
All pulse rise times and fall times must be longer than 10 ns.
> 2 µs
Figure 4. Interlace Timing for Line Skipping Mode
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timing requirements (continued)
Clear Integrate Transfer to Memory Readout
ODB
IAG
SAG
SRG
IAG
SAG SRG
RSG
Expanded Section of Parallel Transfer:
487 Pulses Even Field, 488 Pulses Odd Field
Expanded Section of Serial Transfer
244 Cycles
790 Pulses Line 1790 Pulses Line 244
Pulse Position
Determines Exposure
RSG
TRG
SRG
TRG 140 ns
70 ns
35 ns
> 10 ns > 10 ns > 15 ns
All pulse rise times and fall times must be longer than 10 ns.
> 2 µs
Figure 5. Interlace Timing for Line Summing Mode
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timing requirements (continued)
Clear Integrate Transfer to Memory Readout
ODB
IAG
SAG
SRG
IAG
SAG SRG
RSG
Expanded Section of Parallel Transfer:
488 Pulses
Expanded Section of Serial Transfer
488 Cycles
790 Pulses Line 1790 Pulses Line 244
Pulse Position
Determines Exposure
RSG
TRG
SRG
TRG 140 ns
70 ns
35 ns
> 10 ns > 10 ns > 15 ns
All pulse rise times and fall times must be longer than 10 ns.
> 1 µs
Figure 6. Timing for Progressive Scan Mode
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timing requirements (continued)
SRG
S/H
Clamp
Reset Level Output Signal
Output signal can not be zero for zero charge. Offset level up to 100
RSG
{
mV can be present.
{
Vout
Figure 7. Detail Serial Register Clock Timing for CDS Implementation
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MECHANICAL DATA
The package for the TC341 consists of a ceramic base, a glass window , and a 22-lead frame. The glass window
is sealed to the package by an epoxy adhesive. The package leads are configured in a dual-in-line arrangement
and fit into mounting holes with 1,xx mm center-to-center spacing.
Notes
4204265
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Copyright 2002, Texas Instruments Incorporated
