LX1973A

Microsemi

Integrated Products Division

11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570

Page 1

Copyright

© 2005

Rev. 1.1, 2006-12-15

Automotive Light Sensor

TM

®

DESCRIPTION

The LX1973A is a wide dynamic

range light sensor with a very low

dark current that is optimized for

sensing low level light signals that

typically

occur

under

dark

or

darkening outdoor ambient lighting.

The LX1973A has been optimized for

automotive systems such as headlamp

brightness control or rear view mirror

contrast control. Its radical (fractional

exponent) response when interfaced

with an 8 bit DAC can detect levels

down to 0.001 lux or levels as high as

500 lux.

The spectral response of the

integrated

light

sensor

closely

emulates the human eye so it ignores

light such as infrared which emits

energy but doesn’t aid vision. This

eliminates the need for an Infrared

filter required with competitor’s light

sensors.

The LX1973A internal circuitry

consists

of

a

diode

array

with

Microsemi’s Best Eye™ processing that

provides a nearly perfect photopic light

wavelength response curve. The sensor

output feeds into a wide dynamic range

compression amplifier that provides

accurate resolution over five decades of

ambient light. The integrated dark

current cancellation circuit facilitates

accurate sensing of light below 0.01

lux. The current source output of the

LX1973A can be gain scaled using one

external resistor.

The LX1973A is internally trimmed

to an initial accuracy of 5% at room

temperature and a light level of 10lux.

Accuracy of 10% is maintained over the

full temperature range (-40 to +85°C).

IMPORTANT:

Protected By US Patents: 6,787,757; Patents Pending

KEY FEATUR ES

Nearly Perfect Best Eye™

Human Eye Spectral Response

25C Dark Current <0.005 lux

5 Decades Compressed Output

10% Accuracy Over

Temperature

Scalable Output Voltage

No Optical Filters Needed

APPLI C ATION S

Auto headlamp control

Auto mirror contrast control

PRODUCT H I GHLIGHT

5V

Part

LX1973A

LX1973A Response

0.0

1.0

2.0

3.0

4.0

0.001

0.01

0.1

1

10

100

Ambient Light (in lux)

PACKAGE ORDER INFO

DR

Plastic MSOP Reversed Form

8-Pin

DU

Plastic MSOP

8-pin

RoHS Compliant / Pb-free

RoHS Compliant / Pb-free

-40 to 85

LX1973AIDR

LX1973AIDU

Note: Available in Tape & Reel. Append the letters “TR” to the part number. (i.e. LX1973AIDU-TR)