TCS230
PROGRAMMABLE
COLOR LIGHT-TO-FREQUENCY CONVERTER
TAOS046 - FEBRUARY 2003
1
The
LUMENOLOGY
r
Company
t
t
Copyright
E
2003, TAOS Inc.
www.taosinc.com
D
High-Resolution Conversion of Light
Intensity to Frequency
D
Programmable Color and Full-Scale Output
Frequency
D
Communicates Directly With a Microcontroller
D
Single-Supply Operation (2.7 V to 5.5 V)
D
Power Down Feature
D
Nonlinearity Error Typically 0.2% at 50 kHz
D
Stable 200 ppm/
C Temperature Coefficient
D
Low-Profile Surface-Mount Package
Description
The TCS230 programmable color light-to-frequency converter combines configurable silicon photodiodes and
a current-to-frequency converter on single monolithic CMOS integrated circuit. The output is a square wave
(50% duty cycle) with frequency directly proportional to light intensity (irradiance). The full-scale output
frequency can be scaled by one of three preset values via two control input pins. Digital inputs and digital output
allow direct interface to a microcontroller or other logic circuitry. Output enable (OE) places the output in the
high-impedance state for multiple-unit sharing of a microcontroller input line.
The light-to-frequency converter reads an 8 x 8 array of photodiodes. Sixteen photodiodes have blue filters, 16
photodiodes have green filters, 16 photodiodes have red filters, and 16 photodiodes are clear with no filters.
The four types (colors) of photodiodes are interdigitated to minimize the effect of non-uniformity of incident
irradiance. All 16 photodiodes of the same color are connected in parallel and which type of photodiode the
device uses during operation is pin-selectable. Photodiodes are 120
m x 120
m in size and are on 144-
m
centers.
Functional Block Diagram
Light
Current-to-Frequency
Converter
Photodiode
Array
S2
S3
S0
S1
OE
Output
t
t
Texas Advanced Optoelectronic Solutions Inc.
800 Jupiter Road, Suite 205
S
Plano, TX 75074
S
(972) 673-0759
8 S3
7 S2
6 OUT
5 V
DD
SOIC PACKAGE
(TOP VIEW)
SO 1
S1 2
OE 3
GND 4
TCS230
PROGRAMMABLE
COLOR LIGHT-TO-FREQUENCY CONVERTER
TAOS046 - FEBRUARY 2003
2
t
t
Copyright
E
2003, TAOS Inc.
The
LUMENOLOGY
r
Company
www.taosinc.com
Terminal Functions
TERMINAL
I/O
DESCRIPTION
NAME
NO.
I/O
DESCRIPTION
GND
4
Power supply ground. All voltages are referenced to GND.
OE
3
I
Enable for f
o
(active low).
OUT
6
O
Output frequency (f
o
).
S0, S1
1, 2
I
Output frequency scaling selection inputs.
S2, S3
7, 8
I
Photodiode type selection inputs.
V
DD
5
Supply voltage
Table 1. Selectable Options
S0
S1
OUTPUT FREQUENCY SCALING (f
o
)
S2
S3
PHOTODIODE TYPE
L
L
Power down
L
L
Red
L
H
2%
L
H
Blue
H
L
20%
H
L
Clear (no filter)
H
H
100%
H
H
Green
Available Options
DEVICE
T
A
PACKAGE - LEADS
PACKAGE DESIGNATOR
ORDERING NUMBER
TCS230
- 25
C to 85
C
SOIC-8
D
TCS230D
Absolute Maximum Ratings over operating free-air temperature range (unless otherwise noted)
Supply voltage, V
DD
(see Note 1)
6 V
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Input voltage range, all inputs, V
I
- 0.3 V to V
DD
+ 0.3 V
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Operating free-air temperature range, T
A
0
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
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
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 GND.
Recommended Operating Conditions
MIN
NOM
MAX
UNIT
Supply voltage, V
DD
2.7
5
5.5
V
High-level input voltage, V
IH
V
DD
= 2.7 V to 5.5 V
2
V
DD
V
Low-level input voltage, V
IL
V
DD
= 2.7 V to 5.5 V
0
0.8
V
Operating free-air temperature range, T
A
0
70
C
TCS230
PROGRAMMABLE
COLOR LIGHT-TO-FREQUENCY CONVERTER
TAOS046 - FEBRUARY 2003
3
The
LUMENOLOGY
r
Company
t
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Copyright
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2003, TAOS Inc.
www.taosinc.com
Electrical Characteristics at T
A
= 25
C, V
DD
= 5 V (unless otherwise noted)
PARAMETER
TEST CONDITIONS
MIN
TYP
MAX
UNIT
V
OH
High-level output voltage
I
OH
= -4 mA
4
4.5
V
V
OL
Low-level output voltage
I
OL
= 4 mA
0.25
0.40
V
I
IH
High-level input current
5
A
I
IL
Low-level input current
5
A
I
Supply current
Power-on mode
2
3
mA
I
DD
Supply current
Power-down mode
7
15
A
S0 = H, S1 = H
500
600
kHz
Full-scale frequency (See Note 2)
S0 = H, S1 = L
100
120
kHz
Full scale frequency (See Note 2)
S0 = L, S1 = H
10
12
kHz
Temperature coefficient of output frequency
700 nm, -25
C
T
A
70
C
200
ppm/
C
k
SVS
Supply voltage sensitivity
V
DD
= 5 V
10%
0.5
%/V
NOTE 2: Full-scale frequency is the maximum operating frequency of the device without saturation.
TCS230
PROGRAMMABLE
COLOR LIGHT-TO-FREQUENCY CONVERTER
TAOS046 - FEBRUARY 2003
4
t
t
Copyright
E
2003, TAOS Inc.
The
LUMENOLOGY
r
Company
www.taosinc.com
Operating Characteristics at V
DD
= 5 V, T
A
= 25
C, S0 = H, S1 = H (unless otherwise noted)
(See Notes 3, 4, 5, 6, and 7).
PARAMETER
TEST
CONDITIONS
CLEAR
PHOTODIODE
S2 = H, S3 = L
BLUE
PHOTODIODE
S2 = L, S3 = H
GREEN
PHOTODIODE
S2 = H, S3 = H
RED
PHOTODIODE
S2 = L, S3 = L
UNIT
CONDITIONS
MIN
TYP
MAX
MIN
TYP
MAX
MIN
TYP
MAX
MIN
TYP
MAX
E
e
= 45.6
W/cm
2
,
p
= 470 nm
16
20
24
11.2
16.4
21.6
kHz
f
O
Output
frequency
E
e
= 39.2
W/cm
2
,
p
= 524 nm
16
20
24
8
13.6
19.2
kHz
f
O
frequency
E
e
= 32.8
W/cm
2
,
p
= 635 nm
16
20
24
14
19
24
kHz
E
e
= 0
2
12
2
12
2
12
2
12
Hz
p
= 470 nm
439
360
88
31
R
Irradiance
responsivity
p
= 524 nm
510
189
347
46
Hz/
( W/
R
e
responsivity
(Note 8)
p
= 565 nm
548
49
318
110
(
W/
cm
2
)
(Note 8)
p
= 635 nm
610
30
37
579
cm
2
)
p
= 470 nm
1370
1670
Saturation
Irradiance
p
= 524 nm
1180
1730
W/
Irradiance
(Note 9)
p
= 565 nm
1090
1890
W/
cm
2
(Note 9)
p
= 635 nm
980
1040
p
= 470 nm
585
480
117
41
R
Illuminance
responsivity
p
= 524 nm
98
36
67
9
Hz/
R
v
responsivity
(Note 10)
p
= 565 nm
92
8
53
18
Hz/
lx
(Note 10)
p
= 635 nm
407
20
25
386
f
O
= 0 to 5 kHz
0.1
%
0.1
%
0.1
%
0.1
%
% F.S.
Nonlinearity
(Note 11)
f
O
= 0 to 50 kHz
0.2
%
0.2
%
0.2
%
0.2
%
% F.S.
(Note 11)
f
O
= 0 to 500 kHz
0.5
%
0.5
%
0.5
%
0.5
%
% F.S.
Recovery
from power
down
100
100
100
100
s
Response
time to out-
put enable
(OE)
100
100
100
100
ns
NOTES: 3. Optical measurements are made using small-angle incident radiation from a light-emitting diode (LED) optical source.
4. The 470 nm input irradiance is supplied by an
I
nGaN light-emitting diode with the following characteristics:
peak wavelength
p
= 470 nm, spectral halfwidth
= 35 nm, and luminous efficacy = 75 lm/W.
5. The 524 nm input irradiance is supplied by an
I
nGaN light-emitting diode with the following characteristics:
peak wavelength
p
= 524 nm, spectral halfwidth
= 47 nm, and luminous efficacy = 520 lm/W.
6. The 565 nm input irradiance is supplied by a GaP light-emitting diode with the following characteristics:
peak wavelength
p
= 565 nm, spectral halfwidth
= 28 nm, and luminous efficacy = 595 lm/W.
7. The 635 nm input irradiance is supplied by a Al
I
nGaP light-emitting diode with the following characteristics:
peak wavelength
p
= 635 nm, spectral halfwidth
= 17 nm, and luminous efficacy = 150 lm/W.
8. Irradiance responsivity R
e
is characterized over the range from zero to 5 kHz.
9. Saturation irradiance = (full-scale frequency)/(irradiance responsivity).
10. Illuminance responsivity Rv is calculated from the irradiance responsivity by using the LED luminous efficacy values stated in notes
4, 5, and 6 and using 1 lx = 1 lm/m
2
.
11. Nonlinearity is defined as the deviation of f
O
from a straight line between zero and full scale, expressed as a percent of full scale.
TCS230
PROGRAMMABLE
COLOR LIGHT-TO-FREQUENCY CONVERTER
TAOS046 - FEBRUARY 2003
5
The
LUMENOLOGY
r
Company
t
t
Copyright
E
2003, TAOS Inc.
www.taosinc.com
TYPICAL CHARACTERISTICS
Figure 1
300
500
700
900
Relative Responsivity
1100
- Wavelength - nm
T
A
= 25
C
PHOTODIODE SPECTRAL RESPONSIVITY
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
0
Green
Blue
Normalized to
Clear
@ 680 nm
Red
Clear
Green
Blue
Figure 2
300
500
700
900
Relative Responsivity
1100
- Wavelength - nm
T
A
= 25
C
PHOTODIODE SPECTRAL RESPONSIVITY WITH
EXTERNAL HOYA CM500 FILTER
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
0
Normalized to
Clear
@ 530 nm
Clear
Green
Red
Blue
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