TI TSL401

TSL401
128 × 1 LINEAR SENSOR ARRAY
SOES011 – MARCH 1996
D
D
D
D
D
D
D
128 × 1 Sensor-Element Organization
400 Dots-Per-Inch (DPI) Sensor Pitch
High Linearity and Uniformity
for 256 Gray-Scale (8-Bit) Applications
Output Referenced to Ground
Low Image Lag (0.5% Typical)
Operation to 2 MHz
Single 5-V Supply
(TOP VIEW)
SI
CLK
AO
VDD
1
8
2
7
3
6
4
5
NC
GND
GND
NC
NC – No internal connection
description
The TSL401 linear sensor array consists of a 128 × 1 array of photodiodes and associated charge amplifier
circuitry. The pixels measure 63.5 µm (H) × 50 µm (W) with 63.5-µm center-to-center spacing and 13.5 µm
between pixels. Operation is simplified by internal logic requiring only a serial input (SI) signal and a clock.
functional block diagram
Pixel 1
Integrator
Reset
Pixel
3
Pixel
2
Pixel
128
VDD
Analog
Bus
4
Output
Amplifier
+
_
3
Sample/
Output
6,7
Switch Control Logic
Q1
CLK
SI
2
AO
RL
(External
Load)
Gain
Trim
Q2
Q3
Q128
128-Bit Shift Register
1
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.
Copyright  1996, 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.
•
POST OFFICE BOX 655303 DALLAS, TEXAS 75265
POST OFFICE BOX 1443 HOUSTON, TEXAS 77251–1443
•
1
TSL401
128 × 1 LINEAR SENSOR ARRAY
SOES011 – MARCH 1996
Terminal Functions
TERMINAL
DESCRIPTION
NAME
NO.
AO
3
Analog output
CLK
2
Clock. The clock controls charge transfer, pixel output, and reset.
GND
6, 7
Ground (substrate). All voltages are referenced to the substrate.
NC
5, 8
No internal connection
SI
1
Serial input. This input defines the start of the data-out sequence.
VDD
4
Supply voltage. Supply voltage for both analog and digital circuits.
detailed description
The sensor consists of 128 photodiode pixels, arranged in a linear array. Light energy striking a pixel generates
photocurrent, which is then integrated. The amount of charge accumulated at each pixel is directly proportional
to the light intensity on that pixel and the integration time. The integration time is the interval between two
consecutive output periods.
A 128-bit shift register controls the output period of the device. An output period is initiated by applying a logic
level 1 to SI for one positive-going clock edge (see Figure 1). This logic one is clocked through a 128-bit shift
register, in which one bit is associated with each pixel. When a given bit is high, the associated pixel signal is
coupled to the analog output (AO) through an output amplifier. When the bit goes low, the integrator is reset.
AO is a source follower that requires an external pulldown resistor. The source-follower configuration permits
an analog wired-OR hookup of multiple devices. When the device is not in the output phase, the output is in a
high-impedance state. The output is nominally 0 V for no light input and 2 V for a nominal full-scale output.
The TSL401 is intended for use in a wide variety of applications, including mark and code reading, optical
character recognition (OCR) and contact imaging, edge detection and positioning, and optical linear and rotary
encoding.
2
•
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POST OFFICE BOX 1443 HOUSTON, TEXAS 77251–1443
•
TSL401
128 × 1 LINEAR SENSOR ARRAY
SOES011 – MARCH 1996
absolute maximum ratings†
Supply voltage, VDD . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 V
Digital input current range, II . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . – 20 mA to 20 mA
Operating free-air temperature range, TA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0°C to 70°C
Storage temperature range, Tstg . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . – 25°C to 85°C
Lead temperature 1,6 mm (1/16 inch) from case for 10 seconds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 260°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.
recommended operating conditions (see Figures 1 and 2)
Supply voltage, VDD
Input voltage, VI
MIN
NOM
4.5
5
0
VDD × 0.7
0
High-level input voltage, VIH
Low-level input voltage, VIL
Wavelength of light source, λ
Sensor integration time, tint
Setup time, serial input, tsu(SI)
5.5
V
VDD
VDD
V
5
2000
kHz
0.0645
100
ms
0
V
ns
20
Operating free-air temperature, TA
V
nm
0
Hold time, serial input, th(SI) (see Note 1)
UNIT
VDD × 0.3
700
565
Clock frequency, fclock
MAX
ns
70
°C
NOTE 1: SI must go low before the rising edge of the next clock pulse.
CLK
128 Cycles
Clock Continues or Remains Low After 129th Cycle
128 Cycles
tint
SI
AO
ÇÇÇÇÇ
ÇÇÇÇÇ
Analog
Output Period
ÇÇÇÇ
ÇÇÇÇ
Figure 1. Timing Waveforms
•
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3
TSL401
128 × 1 LINEAR SENSOR ARRAY
SOES011 – MARCH 1996
electrical characteristics at fclock = 200 kHz, VDD = 5 V, TA = 25°C, λp = 565 nm, tint = 5 ms,
RL = 330 Ω, Ee = 20 µW/cm2 (unless otherwise noted) (see Note 2)
PARAMETER
TEST CONDITIONS
Analog output voltage (white, average over 128 pixels)
Analog output voltage (dark, each pixel)
PRNU
MIN
TYP
MAX
1.8
2
2.2
V
0.15
0.3
V
± 5%
± 7.5%
Pixel response nonuniformity
Ee = 0
See Note 3
0
Linearity of analog output voltage
See Note 4
± 0.4%
Output noise voltage
See Note 5
1
Saturation exposure
Analog output saturation voltage
IDD
IIH
Supply current
IIL
Ci
Low-level input current
136
175
3
3.5
2.5
High-level input current
VI = VDD
VI = 0
Input capacitance
UNIT
F.S.
mVrms
nJ/cm2
V
4
mA
1
µA
1
µA
5
pF
NOTES: 2. Clock duty cycle is assumed to be 50%.
3. PRNU is the maximum difference between the voltage from any single pixel and the average output voltage from all pixels of the
device under test when the array is uniformly illuminated.
4. Nonlinearity is defined as the maximum deviation from a best-fit straight line over the dark-to-white irradiance levels, as a percent
of analog output voltage (white).
5. Peak-to-peak noise is the variation of a single-pixel output under constant illumination as observed over a 5-second period.
operating characteristics over recommended ranges of supply voltage and operating free-air
temperature (unless otherwise noted) (see Figure 2)
PARAMETER
TEST CONDITIONS
MIN
TYP
MAX
UNIT
tw(H)
tw(L)
Clock pulse duration (high)
50
ns
Clock pulse duration (low)
50
ns
ts
tv
Analog output settling time to ± 1%
RL = 330 Ω,
CL = 50 pF
Valid time
RL = 330 Ω,
CL = 50 pF,
350
See Note 2
1/(2 fclock)
ns
s
NOTE 2: Clock duty cycle is assumed to be 50%.
tw
1
2
128
129
5V
2.5 V
CLK
0V
tsu(SI)
SI
5V
50%
0V
th(SI)
ts
ts
AO
Pixel 128
Pixel 1
tv
Figure 2. Operational Waveforms
4
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POST OFFICE BOX 655303 DALLAS, TEXAS 75265
POST OFFICE BOX 1443 HOUSTON, TEXAS 77251–1443
•
TSL401
128 × 1 LINEAR SENSOR ARRAY
SOES011 – MARCH 1996
TYPICAL CHARACTERISTICS
PHOTODIODE SPECTRAL RESPONSIVITY
1
TA = 25°C
Normalized Responsivity
0.8
0.6
0.4
0.2
0
300
400
500
700
600
800
900
1000 1100
λ – Wavelength – nm
Figure 3
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POST OFFICE BOX 1443 HOUSTON, TEXAS 77251–1443
•
5
TSL401
128 × 1 LINEAR SENSOR ARRAY
SOES011 – MARCH 1996
APPLICATIONS INFORMATION
This dual-in-line package consists of a circuit mounted on a lead frame and encapsulated with an electrically
nonconductive clear plastic compound.
Pin 1
Pin 2
Pin 3
Pin 4
Pin 5
Pin 6
Pin 7
Pin 8
0.430 (10,92)
0.370 (9,40)
Pixel 4 is centered
horizontally on Pin 1
SI
CLK
AO
VDD
NC
GND
GND
NC
8
5
0.325 (8,26)
0.300 (7,62)
C
L (pixel)
C
L
0.017 (0,43)
0.260 (6,60)
0.240 (6,10)
0.075 (1,91)
0.040 (1,02)
0.030 (0,76) D NOM
1
0.065 (1,65)
0.200 (5,08) 0.045 (1,14)
0.155 (3,94)
15° TYP
4
0.020 (0,51) R NOM
4 Places
7° MAX TYP
0.063 (1,6)
0.059 (1,5)
Seating Plane
0.020 (0,51)
R MAX
4 Places
105°
90°
8 Places
0.012 (0,30)
0.008 (0,20)
0.050 (1,27)
0.020 (0,51)
0.060 (1,52)
0.015 (0,38)
0.300 (7,62)
T.P.†
0.065 (1,65)
0.045 (1,14)
† True position when unit is installed
NOTES: A. All linear dimensions are in inches and parenthetically in millimeters.
B. This drawing is subject ot change without notice.
Figure 4. Packaging Configuration
6
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0.150 (3,81)
0.125 (3,18)
0.022 (0,56)
0.014 (0,36)
0.100 (2,54) T.P.†
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Copyright  1999, Texas Instruments Incorporated