LX1971IDU Microsemi Analog Mixed Signal Group, LX1971IDU Datasheet - Page 4

• Manufacturer Part Number: LX1971IDU
• Description: IC SENSOR LIGHT VISIBLE 8MSOP
• Manufacturer: Microsemi Analog Mixed Signal Group

Specifications of LX1971IDU

• Wavelength: 520nm
• Output Type: Current
• Package / Case: 8-TSSOP, 8-MSOP (0.118", 3.00mm Width)
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Copyright © 2003
Rev. 1.1b,2005-08-10
The following curves show the calculated responsiveness of
the LX1971 without load resistors based on the formulas
above. They can be used as baseline guidelines to calculate
gain setting resistors. The compliance of the current source
output may result in premature saturation of the output when
load resistors are added. The SRC compliance voltage is
specified typically at VDD-600mV @ about 4000 lux.
that resembles the human visual system. It is packaged in
clear MSOP package with the same pin out and same
supply voltage range as Microsemi’s LX1970 light sensor.
The LX1971 responsiveness however differs from that of
the LX1970. In general the LX1971 has lower sensitivity
and a wider dynamic range.
directly proportional to the intensity of light falling on the
photo receptors. There are two different response equations
for the LX1971 depending on the operating range (intensity
of the light). Below 2500 lux, the response resembles a
square root function. Above 2500 lux, the response fits a
straight line curve.
20000 lux
light sensor is an integral part of a continuous lighting
control system.
application, the level of brightness of the backlight should
be adjusted in proportion to the level of ambient lighting;
the LX1970 can provide closed loop brightness control for
this type of system. For most indoor applications, the 2500
lux saturation point of the LX1970 is usually not a limiting
affect.
system must respond to external events that affect the
user’s ability to see clearly. For example, a sensor to turn
on headlights or a sensor to adjust the reflectivity of a rear
view mirrors. These systems require the sensor to have
dynamic range similar to sight. Like the human eye, the
square root function of the LX1971 makes it extra sensitive
to small changes at lower light levels. The wide dynamic
range allows the LX1971 to sense the difference between
twilight and daylight or sunshine and heavy cloud cover.
The LX1971 is a light sensor with a spectral response
Whereas the LX1970 has a responsiveness that is
The LX1970 is best suited for applications where the
The LX1971 is best suited for applications where the
I
I
OUT
OUT
=
=
I N T E G R A T E D
(
(
L
L
×
×
.
0083
.
For example, in an LCD backlighting
808
11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: [phone]
µ
)
+
A
. 1
)
+
µ 1
23
A
µ
for L < 2500 lux
A
P R O D U C T S
for 2500 lux < L <
A P P L I C A T I O N I N F O R M A T I O N
Integrated Products
Microsemi
50
40
30
20
10
250
200
150
100
Wide Range Visible Light Sensor
250
200
150
100
LX1971 Calculated SRC Low Level Response
0
50
50
LX1971 Calculated SRC High Level Response
LX1971 Calculated SRC Full Range Response
0
0
0
0
0
P
RODUCTION
500
5000
5000
Incandescent Light (lux)
Incandescent Light (lux)
Incandescent Light (lux)
>2500 Lux Formula
10000
1000
<2500 Lux Formula
10000
<2500 Lux Formula
>2500 Lux Formula
D
ATA
15000
1500
15000
S
HEET
20000
20000
2000
25000
25000
2500
LX1971
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