TSL237
HIGH-SENSITIVITY
LIGHT-TO-FREQUENCY CONVERTER
TAOS052J SEPTEMBER 2008
PACKAGE S PACKAGE SM
High-Resolution Conversion of Light
SIDELOOKER SURFACE MOUNT
Intensity to Frequency With No External
(FRONT VIEW) SIDELOOKER
Components
(FRONT VIEW)
High Irradiance Responsivity . . .
2
2.3 kHz/(W/cm ) at = 524 nm
p
Low Dark Frequency ...< 2 Hz at 50 C
Single-Supply Operation . . . 2.7 V to 5.5 V
Stable 200 ppm/C Temperature Coefficient
Interfaces Directly to a Microcontroller
RoHS Compliant (LF Package Only)
1 2 3
GND V OUT
DD
1 2 3
GND V OUT
DD
Description
The TSL237 light-to-frequency converter combines a silicon photodiode and a current-to-frequency converter
on a single monolithic CMOS integrated circuit. Output is a square wave (50% duty cycle) with frequency directly
proportional to light intensity (irradiance) on the photodiode. The digital output allows direct interface to a
microcontroller or other logic circuitry. The device has been temperature compensated for the
ultraviolet-to-visible light range of 320 nm to 700 nm and responds over the light range of 320 nm to 1050 nm.
The TSL237 is characterized for operation over the temperature range of 40C to 85C and is supplied in a
3-lead clear plastic side-looker package with an integral lens. When supplied in the lead (Pb) free package, the
device is RoHS compliant.
For automotive and other extended temperature applications, please contact TAOS for information.
Functional Block Diagram
Current-to-Frequency
Light Photodiode Output
Converter
Available Options
DEVICE T PACKAGE LEADS PACKAGE DESIGNATOR ORDERING NUMBER
A
TSL237 40C to 70C 3-lead Sidelooker S TSL237S
TSL237 40C to 70C 3-lead Sidelooker Lead (Pb) Free S TSL237SLF
TSL237 40C to 70C 3-lead Surface-Mount Sidelooker Lead (Pb) Free SM TSL237SMLF
Copyright 2008, TAOS Inc.
The LUMENOLOGY Company
Texas Advanced Optoelectronic Solutions Inc.
1001 Klein Road Suite 300 Plano, TX 75074 (972) 673-0759
www.taosinc.com 1TSL237
HIGH-SENSITIVITY
LIGHT-TO-FREQUENCY CONVERTER
TAOS052J SEPTEMBER 2008
Terminal Functions
TERMINAL
TYPETYPE DESCRIPTIONDESCRIPTION
NAME NO.
GND 1 Power supply ground (substrate). All voltages are referenced to GND.
OUT 3 O Output frequency.
V 2 Supply voltage.
DD
Absolute Maximum Ratings over operating free-air temperature range (unless otherwise noted)
Supply voltage, V (see Note 1) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 V
DD
Operating free-air temperature range, T (see Note 2) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40C to 85C
A
Storage temperature range, T (see Note 2) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40C to 85C
stg
Lead temperature 1,6 mm (1/16 inch) from case for 10 seconds (S Package) . . . . . . . . . . . . . . . . . . . . 260C
Reflow solder, in accordance with J-STD-020C or J-STD-020D (SM Package) . . . . . . . . . . . . . . . . . . . 260C
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.
NOTES: 1. All voltage values are with respect to GND.
2. Long-term storage or operation above 70C could cause package yellowing that will lower the sensitivity to wavelengths < 500nm.
Recommended Operating Conditions
MIN NOM MAX UNIT
Supply voltage, V 2.7 5 5.5 V
DD
Operating free-air temperature range, T 40 70 C
A
Electrical Characteristics at V = 5 V, T = 25C (unless otherwise noted)
DD A
PARAMETER TEST CONDITIONS MIN TYP MAX UNIT
V High-level output voltage I = 1 mA 4 4.5 V
OH OH
V Low-level output voltage I = 1 mA 0.25 0.4 V
OL OL
I Supply current 2 3 mA
DD
Full-scale frequency 500 1000 kHz
Temperature coefficient of responsivity Wavelength < 600nm, f = 50 kHz 200 ppm/C
O
k Supply-voltage sensitivity V = 5 V 10% 0.5 %/V
SVS DD
Full-scale frequency is the maximum operating frequency of the device without saturation.
Operating Characteristics at V = 5 V, T = 25C, p = 524 nm (unless otherwise noted)
DD A
PARAMETER TEST CONDITIONS MIN TYP MAX UNIT
2
f Output frequency E = 21.8 W/cm 40 50 60 kHz
O e
2
E = 0 W/cm 0 0.1 Hz
e
ff Dark frequencyDark frequency
D
2
E = 0 W/cm , TA = 50C 0 2 Hz
e
kHz/(W/
R Irradiance responsivity 2.3
e 2
cm )
f = 0 kHz to 10 kHz 1% %F.S.
Nonlinearity
O
1 pulse of new
Step response to full-scale step input
frequency plus 1 s
Nonlinearity is defined as the deviation of f from a straight line between zero and full scale, expressed as a percent of full scale.
O
Copyright 2008, TAOS Inc. The LUMENOLOGY Company
2 www.taosinc.com