ISL29102_14 Datasheet, PDF (7/9 Pages) Intersil Corporation – Low Power Ambient Light-to-Voltage Non-Linear Converter

ISL29102
Application Information
Light-to-Voltage Conversion
The ISL29102 has responsiveness that is a square-root
function of the light intensity intercepted by the photodiode in
lux. Because the photodiode has a responsivity that
resembles the human eye, conversion rate is independent of
the light source (fluorescent light, incandescent light or direct
sunlight).
V_OUT
=
----¹---^.--⁸----^μ----^A-----
100 l u x
E × R_EXT
(EQ. 1)
In Equation 1, V_OUT is the output voltage, E is the light
intensity and R_EXT is the value of the external resistor. The
R_EXT is used to set the light-to-voltage scaling constant. The
compliance of the ISL29102's output circuit may result in
premature saturation when an excessively large R_EXT is
used. The output compliance voltage is 700mV below the
supply voltage as listed in V_O-MAX of the “Electrical
Specifications” table on page 3.
Optical Sensor Location Outline
The green area in Figure 18 shows the optical sensor
location outline of ISL29102. Along the pinout direction, the
center line (CL) of the sensor coincides with that of the
packaging. The sensor width in this direction is 0.39mm.
Perpendicular to the pinout direction, the CL of the sensor
has an 0.19mm offset from the CL of packaging away from
pin 1. The sensor width in this direction is 0.46mm.
2.10mm
2.00mm
0.19mm
0.39mm
FIGURE 18. 6 LD ODFN SENSOR LOCATION OUTLINE
0.46mm
7
FN6483.1
July 15, 2010