TSL238

HIGH-SENSITIVITY

LIGHT-TO-FREQUENCY CONVERTER

TAOS073J − SEPTEMBER 2008

1

The LUMENOLOGY

r Company

r

r

Copyright

E 2008, TAOS Inc.

www.taosinc.com

Intensity to Frequency With No External

Components

2.3 kHz/(

Description

The TSL238 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. Output enable (OE) places the output in a high-impedance state for

multiple-unit sharing of a microcontroller input line. 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 TSL238 is characterized for operation over the temperature range of −40

°C to 85°C and is supplied in an

8-lead plastic small outline package. 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

Light

Current-to-Frequency

Converter

Photodiode

Output

Available Options

DEVICE

PACKAGE − LEADS

PACKAGE DESIGNATOR

ORDERING NUMBER

TSL238

−25

°C to 70°C

8-lead Plastic Small Outline IC

D

TSL238D

r

r

Texas Advanced Optoelectronic Solutions Inc.

1001 Klein Road

S Suite 300 S Plano, TX 75074 S (972) 673-0759

8 OUT

6 GND

5 OE

PACKAGE D

8-LEAD SOIC

(TOP VIEW)

NC 1

NC 2

NC 3

NC 4