TSL238T

HIGH-SENSITIVITY

LIGHT-TO-FREQUENCY CONVERTER

TAOS080G − DECEMBER 2007

1

The LUMENOLOGY r Company

r

r

Copyright E 2007, TAOS Inc.

www.taosinc.com

Intensity to Frequency With No External

Components

Description

The TSL238T 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 TSL238T is characterized for operation over the temperature range of −40°C to 85°C and is supplied in

a compact 4-lead surface-mount package that is lead (Pb) free and RoHS compliant.

Functional Block Diagram

Light

Current-to-Frequency

Converter

Photodiode

Output

Available Options

DEVICE

PACKAGE − LEADS

PACKAGE DESIGNATOR ORDERING NUMBER

TSL238T

−40°C to 85°C

4-lead Low Profile Surface Mount

T

TSL238T

Terminal Functions

TERMINAL

NAME

T PKG

NO.

TYPE

DESCRIPTION

GND

2

Power supply ground (substrate). All voltages are referenced to GND.

OE

1

I

OUT

4

O

Output frequency.

3

Supply voltage.

r

r

Texas Advanced Optoelectronic Solutions Inc.

1001 Klein Road S Suite 300 S Plano, TX 75074 S (972) 673-0759

PACKAGE T

4-LEAD SMD

(TOP VIEW)

OE 1

GND 2

4 OUT