LX1970MINI Datasheet, PDF (1/1 Pages) Microsemi Corporation – LX1970 Light Sensor

INTEGRATED PRODUCTS
LX1970 Mini Control Board
LX1970 Light Sensor
SCHEMATIC
C1
0.1µF
R3
VDD
1
VDD
8
VSS
GND
2
7
R1
NC
NC
3
6
NC
NC
VOUT
4
5
SOURCE SINK
C2
4.7µF
LX1970DU
R2
The LX1970 Mini Light Sensor Board can be used to convert a manual DC
voltage dimmer to a closed loop automatic dimmer. The resistor values can be
changed to fit the design requirements. The LX1970 output current is
proportional to the incident light intensity up to the point where either the
current source voltage compliance is exceeded or the light sensor saturates. See
the data sheet and application note for additional information.
PHOTO
V _OUT
[( = I _SRC
× R1 ) + V _DD ]×
R2
R1 + R2
The value of R3 is typically less than 1K and is used as a power filter for the
LX1970 if the VDD line is excessively noisy.
PACKAGE PIN OUT
With VDD = 3.0V, R1 = 150K, R2 = 30K and R3 = 0, the current output ^VDD
1
active area 8
VSS
voltage in total darkness is VDD x R2/ (R1 + R2) = 0.5V. The maximum output NC
2
7
NC
voltage is approximately VDD – 0.3 = 2.7V, which is limited by the output _NC
3
voltage compliance at a current of 2.7V x (R1 + R2) / (R1 x R2) = 108uA.
SRC
4
6
NC
5
SNK
Protected by U.S. Patents: 6,787,757; Patents Pending.
DU PACKAGE
(Top View)
NAME
V_DD
V_SS
SNK
SRC
FUNCTIONAL PIN DESCRIPTION
DESCRIPTION
Input Supply Voltage (Some boards wired with a RED pigtail.)
Ground Reference for Power and Signal Output (Some boards wired with a BLACK pigtail.)
Output Current Sink
Output Current Source (Some boards wired with a YELLOW pigtail.)
1/27/2005
Rev 1.0a
Microsemi
Integrated Products
11861 Western Avenue, Garden Grove CA. 92841 714-898-8121, FAX: [phone]