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TSL235R
LIGHT TO FREQUENCY CONVERTER
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TAOS038 鈥?APRIL 2002
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High-Resolution Conversion of Light
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Intensity to Frequency With No External
Components
Communicates Directly With a
Microcontroller
Package
Single-Supply Operation Down to 2.7 V
Nonlinearity Error Typically 0.2% at 100 kHz
Stable 150 ppm/擄C Temperature Coefficient
Single-Supply Operation
PACKAGE
(FRONT VIEW)
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Compact Three-Leaded Clear-Plastic
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1
2
3
GND V
DD
OUT
Description
The TSL235R 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 TSL235R is characterized for operation over the temperature range of 鈥?5擄C to 70擄C and is supplied in
a 3-lead clear plastic side-looker package with an integral lens.
Functional Block Diagram
Light
Photodiode
Current-to-Frequency
Converter
Output
The
LUMENOLOGY
r
Company
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Copyright
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2002, TAOS Inc.
Texas Advanced Optoelectronic Solutions Inc.
800 Jupiter Road, Suite 205
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Plano, TX 75074
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(972) 673-0759
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www.taosinc.com
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