LX1972A

Microsemi

Integrated Products Group

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

Page 1

Ambient Light Detector

Copyright

© 2005

Rev. 1.0, 2006-09-18

TM

®

DESCRIPTION

The LX1972A is a low cost silicon

light sensor with a spectral response

that closely emulates the human eye.

Patented circuitry produces peak

spectral response at 580nm, with an IR

response less than ±5% of the peak

response, above 900nm.

The photo sensor is a PIN diode

array with Microsemi’s Best Eye™

processing that provides a nearly

perfect photopic light wavelength

response curve. LX1972A provides a

linear, accurate, and very repeatable

current transfer function. High gain

current mirrors on the chip multiply

the PIN diode photo-current to a

sensitivity level that can be voltage

scaled with a standard value external

resistor. Output current from this

simple to use two-pin device can be

used directly or converted to a voltage

by placing it in series with a single

resistor at either of its two pins.

Dynamic range is determined by the

resistors (typically in the range of 5K to

100K) and the power supply values.

Typically the LX1972A needs only

2.7V of headroom to operate at 1000

Lux illumination.

Internal temperature compensation

allows dark current to be kept below

200nA over the full specification

temperature range (-40°C to +85°C),

providing high accuracy at low light

levels. Usable ambient light conditions

range is from 1 to more than 5000 Lux.

The LX1972A is optimized for

controlling back lighting systems in low

cost consumer products such as LCD

TV, portable computers, and digital

cameras.

IMPORTANT:

Protected By U.S. Patents: 6,787,757; Patents Pending

KEY FEATUR ES

Near Human Eye Spectral

Response

Very Low IR Sensitivity

Highly Accurate & Repeatable

Output Current vs. Light

Scalable Output Voltage

Temperature Stable

Integrated High Gain Photo

Current Amplifiers

No Optical Filters Needed

APPLI C ATION S

Portable Electronic Displays

LCD TV Backlight Systems

Digital Still Cameras (DSC)

Desk Top Monitors

Notebook Computers

PRODUCT H I GHLIGHT

1.7V Typical

@ 100 Lux

Ambient Light

LX1972A

LX1972A

PACKAGE ORDER INFO

BC

Plastic 1206

2-Pin

RoHS Compliant / Pb-free

-40 to 85

LX1972AIBC

Note: Available in Tape & Reel. Append the letters “TR” to

the part number. (i.e. LX1972AIBC-TR)