TI TSL220

TSL220
LIGHT-TO-FREQUENCY CONVERTER
SOES003 – AUGUST 1990 – REVISED JUNE 1991
D
D
D
D
D
D
D
D
High-Resolution Conversion of Light Intensity to Frequency
Wide Dynamic Range . . . 118 dB
Variable (and Single) Supply Range . . . 5 V to 10 V
High Linearity . . . Typically Within 2% of FSR (C = 100 pF)
High Sensitivity . . . Can Detect Change of 0.01% of FSR
CMOS Compatible Output for Digital Processing
Minimum External Components
Microprocessor Compatible
description
The TSL220 consists of a large-area photodiode and a current-to-frequency converter. The output voltage is
a pulse train and its frequency is directly proportional to the light intensity (irradiance) on the photodiode. The
output is CMOS† compatible and its frequency may be measured using pulse counting, period timing, or
integration techniques. The TSL220 is ideal for light-sensing applications requiring wide dynamic range, high
sensitivity, and high noise immunity. The output frequency range is determined by an external capacitor; hence,
the desired output frequency is adjustable for a given light intensity at the input. The TSL220 is characterized
for operation over the temperature range of – 25°C to 70°C.
mechanical data
The photodiode and current-to-frequency converter are packaged in a clear plastic 8-pin dual-in-line package.
The active chip area is typically 4,13 mm2 (0.0064 in2).
9,2 (0.362)
8,7 (0.343)
4
PIN 1 NC
PIN 2 OUTPUT
PIN 3 VCC
PIN 4 C2
PIN 5 GND
PIN 6 C1
PIN 7 NU
PIN 8 NU
3
2
1
Location of
Photodiode
Center
C
L
0,8 (0.031) R NOM
5
NC–No internal connection
NU–Not usable (leave unconnected)
6
7
8
2,4 (0.094)
1,9 (0.075)
C
L
0,6 (0.024)
0,4 (0.016)
5,6 (0.220)
5,4 (0.213)
1,6 (0.063)
1,4 (0.055)
6,5 (0.256)
6,3 (0.248)
7°
TYP
105°
90°
8 Places
9,5 (0.374)
MAX
7° MAX
TYP
0,84 (0.033) MIN
7,82 ± 0,13
(0.308 ± 0.005)
Seating Plane
0,30 (0.012)
0,23 (0.009)
0,85 (0.033)
0,45 (0.018)
3,4 (0.134)
3,2 (0.126)
0,56 (0.022)
0,36 (0.014)
2,54 ± 0,10
(0,100 ± 0.004)
ALL LINEAR DIMENSIONS ARE IN MILLIMETERS AND PARENTHETICALLY IN INCHES
† Use of LSTTL logic families may require a 3300-Ω pulldown resistor on the output.
Copyright  1991, 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
1
TSL220
LIGHT-TO-FREQUENCY CONVERTER
SOES003 – AUGUST 1990 – REVISED JUNE 1991
functional block diagram
TSL220
Light
I/f
Current to
Frequency
Converter
Photodiode
absolute maximum ratings over operating free-air temperature range (unless otherwise noted)
Supply voltage, VCC (see Note 1) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 V
Operating free-air temperature, TA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . – 25°C to 70°C
Storage temperature range . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . – 25°C to 85°C
Lead temperature 1,6 mm (1/16 inch) from case for 10 seconds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 260°C
NOTE 1: All voltage values are with respect to GND (pin 5).
recommended operating conditions
Supply voltage, VCC
MIN
NOM
MAX
4
5
10
V
750
kHz
70
°C
Output frequency, fo (C ≤ 100 pF)
Operating free-air temperature range, TA
– 25
UNIT
electrical characteristics at VCC = 5 V, TA = 25°C (see Figure 1)
PARAMETER
VOM
ICC
TEST CONDITIONS
Peak output voltage
RL = 50 kΩ
Supply current
C = 100 pF,
MIN
TYP
3
4
Ee = 0
MAX
UNIT
V
7.5
10
mA
MIN
TYP
MAX
UNIT
50
150
250
kHz
0
1
50
Hz
operating characteristics at VCC = 5 V, TA = 25°C (see Figure 1)
PARAMETER
TEST CONDITIONS
fo
Output frequency
Ee = 125 µW/cm2,
Ee = 0,
tw
tr
Output pulse duration
C = 470 pF
1
µs
Output pulse rise time
C = 100 pF
20
ns
tf
Output pulse fall time
C = 100 pF
120
ns
2
POST OFFICE BOX 655303
λ = 880 nm,
C = 100 pF
• DALLAS, TEXAS 75265
C = 100 pF
TSL220
LIGHT-TO-FREQUENCY CONVERTER
SOES003 – AUGUST 1990 – REVISED JUNE 1991
PARAMETER MEASUREMENT INFORMATION
VCC
6
3
2
TSL220
C
tw
Output
VOM
90%
50%
RL
10%
4
tr
5
TEST CIRCUIT
0
tf
OUTPUT WAVEFORM
NOTE: Output waveform is monitored on an oscilloscope with the following characteristics: Ri ≥ 1 MΩ, Ci ≤ 6.5 pF.
Figure 1. Switching Times
TYPICAL CHARACTERISTICS
OUTPUT PULSE DURATION
vs
EXTERNAL CAPACITOR VALUE
PEAK OUTPUT VOLTAGE
vs
LOAD RESISTANCE
10,000
5
VCC = 5 V
TA = 25° C
4.5
V OM – Peak Output voltage – V
tw – Output Pulse Duration – µ s
100,000
1000
100
10
1
4
VCC = 5 V
TA = 25°C
3.5
3
2.5
2
1.5
1
0.5
0.1
1 p 10 p 100 p 1 n 10 n 100 n 1 µ 10 µ 100 µ 1 m
0
10 M
C – External Capacitor Value – F
Figure 2
1M
100 k
10 k
1k
100
RL – Load Resistance – Ω
10
Figure 3
POST OFFICE BOX 655303
• DALLAS, TEXAS 75265
3
TSL220
LIGHT-TO-FREQUENCY CONVERTER
SOES003 – AUGUST 1990 – REVISED JUNE 1991
TYPICAL CHARACTERISTICS
OUTPUT FREQUENCY
vs
IRRADIANCE
NORMALIZED OUTPUT FREQUENCY
vs
LOAD RESISTANCE
1000
1.3
C = 27 pF
1.2
100
Normalized Output Frequency
f o – Output Frequency – kHz
VCC = 5 V
λ = 930 nm
TA = 25° C
C = 470 pF
10
1
C = 0.1 µF
0.1
VCC = 5 V
C = 100 pF
TA = 25° C
1.1
1.0
0.9
0.8
0.7
0.6
0.5
1M
0.01
1
1000
10
100
Ee – Irradiance – µW/cm2
100 k
10 k
1k
100
RL – Load Resistance – Ω
Figure 4
Figure 5
NORMALIZED OUTPUT FREQUENCY
vs
FREE-AIR TEMPERATURE
OUTPUT FREQUENCY
vs
EXTERNAL CAPACITOR VALUE
1.4
100
VCC = 5 V
TA = 25° C
1.3
Normalized Output Frequency
10
Normalized Output Frequency
10
1
0.1
0.01
VCC = 5 V
C = 100 pF
Ee = 75 µW/cm2
Light Source: Tungsten Filament Lamp
1.2
1.1
1.0
0.9
0.8
0.001
0.7
0.001
0.01
0.1
1
10
100
1000
C – Capacitance – nF
0.6
10 20 30 40 50
–30 –20 –10 0
TA – Free-Air Temperature – °C
Figure 6
4
Figure 7
POST OFFICE BOX 655303
• DALLAS, TEXAS 75265
60
70
TSL220
LIGHT-TO-FREQUENCY CONVERTER
SOES003 – AUGUST 1990 – REVISED JUNE 1991
TYPICAL CHARACTERISTICS
SUPPLY CURRENT
vs
FREE-AIR TEMPERATURE
SUPPLY CURRENT
vs
SUPPLY VOLTAGE
1.15
16
14
13
12
11
10
9
8
VCC = 5 V
C = 100 pF
RL = 1 MΩ
Light Source: Tungsten
Filament Lamp
1.1
1.05
1
0.95
0.9
7
0.85
10 20 30 40 50
–30 –20 –10 0
TA – Free-Air Temperature – °C
6
4
5
6
7
8
9
10
VCC – Supply Voltage – V
Figure 8
60
70
Figure 9
PHOTODIODE SPECTRAL RESPONSE
1
TA = 25°C
0.9
0.8
Normalized Response
I CC – Supply Current – mA
15
Normalized Supply Current
Ee = 0
C = 100 pF
RL = 1 MΩ
TA = 25° C
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0
300
400
500
600 700 800 900
λ ± Wavelength – nm
1000 1100
Figure 10
POST OFFICE BOX 655303
• DALLAS, TEXAS 75265
5
TSL220
LIGHT-TO-FREQUENCY CONVERTER
SOES003 – AUGUST 1990 – REVISED JUNE 1991
APPLICATION INFORMATION
VCC
VCC
4 16
J
K
3
6
OUT
2
1
5
15
Q
CLK
TSL220
C
1/2 SN74HC76
4
5
13
Figure 11. Light-to-Frequency Converter with Square-Wave Output
VCC
Ambient Light
VCC
1 kΩ
3
To Blanking Inputs (BI)
6
2
OUT
TSL220
C
2N3904
or Equivalent
100 Ω
BI
BI
BI
4
TIL 306,307,308,309,311
5
NOTE: Adjust C to set maximum and minimum brightness levels.
Figure 12. Automatic Display Dimming Circuit
fo
TSL220
Counter
Latch
Reset
Clock
Enable
Delay
Figure 13. Light-to-Digital Converter
6
POST OFFICE BOX 655303
• DALLAS, TEXAS 75265
Digital Output
TSL220
LIGHT-TO-FREQUENCY CONVERTER
SOES003 – AUGUST 1990 – REVISED JUNE 1991
APPLICATION INFORMATION
5V
Over
Range
16
5V
5
16
LS
MSD
TIL306
CLR
PC
BI
14
SC
10
9
TIL306
CLR
PC
BI
8
14
SC
16
TIL306
12
9
CLR
PC
BI
14
8
SC
16
LS
7 MAX
15
CK
CNT
10
5V
5
LS
7 MAX
15
CK
CNT
12
5V
5
LS
7 MAX
15
CK
CNT
12
5V
16
5
10
9
LS
7 MAX
15
CK
CNT
7 MAX
15
CK
CNT
TIL306
12
CLR
PC
BI
8
14
SC
5
TIL306
10
12
9
CLR
PC
BI
8
14
SC
5V
3
LSD
6
9
2
fo
10
C
4
TSL220
1 kΩ
5
8
5V
5V
to
to
tLS
8
120 K
4
16
7
1K
22 K
tLS
3
15
NE555
100 pF
6
14
Q
4
SN74123
2
2
2.2 µF
3
1
8
1
Figure 14. Simple Digital Light Meter
VCC
6
3
OUT
2
Port or
Interrupt
Input
µP
TSL220
C
4
5
Figure 15. Light Detector with Direct Microprocessor Interface
POST OFFICE BOX 655303
• DALLAS, TEXAS 75265
7
TSL220
LIGHT-TO-FREQUENCY CONVERTER
SOES003 – AUGUST 1990 – REVISED JUNE 1991
APPLICATION INFORMATION
VCC
VCC
VCC
6
4 16
5
J
K
CLK
Q
3
OUT
C
2
TSL220
1
VCC
14
16
1/2
SN74HC153
7
6
Y
C0
5
C1
4
C2
3
C3
14
A
2
B
SN74HC4024
1
15
CK
QA
QB
SN74HC76
5
11
9
QC
6
QD
4
2
12
CLR
7
1
Output
To µP
Range
Select
Inputs
8
From µP
NOTE: Adjust C for useful frequency range.
Figure 16. Light Detector with Microprocessor (Microcontroller) and Autoranging Capability
VCC
3
6
OUT
TSL220
C
2
÷N
Counter
fo ÷ N
Binary
Counter
4
5
L
F
SN74HC4024
SN74HC4040
SN74HC161
Prescale
Counter
Figure 17. Digital Light Integrator
8
POST OFFICE BOX 655303
• DALLAS, TEXAS 75265
Binary
Output
TSL220
LIGHT-TO-FREQUENCY CONVERTER
SOES003 – AUGUST 1990 – REVISED JUNE 1991
APPLICATION INFORMATION
LSD
VCC
VCC
16 5
3
LS
6
OUT
C
4
VCC
16 5
2
÷N
CK MAX
15
CNT
TSL220
5
12
Prescale
CLR
PC
BI
Reset
14
SC
7
15
10
9
12
TIL306
LS
CK MAX
CNT
SC
CLR
PC
BI
8
LS
15
7
10
9
12
CLR
SC
PC
10
9
14 8
TIL306
TIL306
Ct
Rt
VCC
6
0.01 µF
5
1
CK
BI
14 8
7
MSD
VCC
16 5
8
NE555
4
Exposure time = 1.1 Rt Ct
Start
2
3
Figure 18. Digital Light Exposure Meter
POST OFFICE BOX 655303
• DALLAS, TEXAS 75265
9
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