TSL238
HIGH-SENSITIVITY
LIGHT-TO-FREQUENCY CONVERTER
TAOS073J SEPTEMBER 2008
3
The LUMENOLOGY r Company
r
r
Copyright E 2008, TAOS Inc.
www.taosinc.com
Electrical Characteristics at V
DD
= 5 V, T
A
= 25?/SPAN>C (Note 1) (unless otherwise noted)
PARAMETER
TEST CONDITIONS
MIN
TYP
MAX
UNIT
V
OH
High-level output voltage
I
OH
= 1 mA
4
4.5
V
V
OL
Low-level output voltage
I
OL
= 1 mA
0.25
0.4
V
I
IH
High-level input current
10
10
糀
I
IH
Low-level input current
10
10
糀
I
DD
Supply current
E
e
= 21.2 糤/cm
2
2
3
mA
Full-scale frequency (Note 2)
T
A
= 50癈 (Note 3)
500
1000
kHz
Temperature coefficient of responsivity
Wavelength < 600nm, f
O
= 50 kHz
?00
ppm/癈
k
SVS
Supply-voltage sensitivity
V
DD
= 5 V ?0%
?.5
%/V
NOTES:  1.  The input irradiance is supplied with green LED light source with peak wavelength = 524 nm.
2.  Full-scale frequency is the maximum frequency of the device without saturation. Higher irradiance will not result in any additional
increase of output frequency. The output frequency will remain at approximately the saturation frequency to a minimum of 1000
糤/sqcm 524-nm irradiance. During production testing, devices are not tested at this very high irradiance level.
3.  Measured at wafer probe using 50癈 hot chuck.
Operating Characteristics at V
DD
= 5 V, T
A
= 25?/SPAN>C, ?/SPAN>p = 524 nm (unless otherwise noted)
PARAMETER
TEST CONDITIONS
MIN
TYP
MAX
UNIT
f
O
Output frequency
E
e
= 21.2 糤/cm
2
40
50
60
kHz
E
e
= 0 糤/cm
2
0
1.2
Hz
f
D
Dark frequency
E
e
= 0 糤/cm
2
, TA = 50癈 (Note 1)
0
6
Hz
R
e
Irradiance responsivity
2.3
kHz/(糤/
cm
2
)
籶
Peak response wavelength
700
nm
Nonlinearity (Note 2)
f
O
= 0 kHz to 10 kHz
?%
%F.S.
Step response to full-scale step input
1 pulse of new
frequency plus 1 約
Time from OE
low to output enabled
1 period of output
frequency
NOTES:  1.  Measured at wafer probe using 50癈 hot chuck.
2.  Nonlinearity is defined as the deviation from a straight line between zero and maximum of stated range, expressed as a percent
of stated range.