LX1972

Microsemi

Integrated Products Division

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

Page 1

Ambient Light Detector

Copyright

© 2004

Rev. 1.1b, 2005-10-31

TM

®

DESCRIPTION

The LX1972 is a low cost silicon

light sensor with spectral response that

closely emulates the human eye.

Patented circuitry produces peak

spectral response at 520nm, with IR

response less than ±5%, of the peak

response, above 900nm.

The photo sensor is a PIN diode array

with 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 10K

to 100K) and power supply values.

Typically the LX1972 needs only 1.8V

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 to +85°C),

providing high accuracy at low light

levels. Usable ambient light conditions

range is from 1 to more than 5000 Lux.

The LX1972 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

LX1972

V

DD

V

SS

1.2V Typical

@ 100 Lux

V

DD

V

SS

Ambient Light

LX1972 Top View

PACKAGE ORDER INFO

BC

Plastic 1206

2-Pin

RoHS Compliant / Pb-free

-40 to 85

LX1972IBC

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

the part number. (i.e. LX1972IBC-TR)