HSDL-3211-021 Avago Technologies US Inc., HSDL-3211-021 Datasheet - Page 17

• Manufacturer Part Number: HSDL-3211-021
• Description: Infrared Transceivers Short Distance 3V M IR
• Manufacturer: Avago Technologies US Inc.

Specifications of HSDL-3211-021

• Wavelength: 875 nm, 880 nm
• Continual Data Transmission: 1.152 Mbit/s
• Transmission Distance: 50 cm
• Radiant Intensity: 45 mW/sr
• Half Intensity Angle Degrees: 30 deg
• Pulse Width: 4 us, 1.6 us
• Maximum Rise Time: 25 ns, 40 ns
• Maximum Fall Time: 25 ns, 40 ns
• Led Supply Voltage: 0 V to 6.5 V
• Maximum Forward Current: 150 mA
• Operating Voltage: 2.4 V to 3.6 V
• Maximum Operating Temperature: + 85 C
• Minimum Operating Temperature: - 25 C
• Dimensions: 8 mm x 3 mm x 2.5 mm
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

17
Window Material
Almost any plastic material will
work as a window material.
Polycarbonate is recommended.
The surface finish of the plastic
should be smooth, without any
texture. An IR filter dye may be
used in the window to make it
look black to the eye, but the
total optical loss of the window
should be 10% or less for best
optical performance. Light loss
should be measured at 875 nm.
The recommended plastic
materials for use as a cosmetic
window are available from
General Electric Plastics.
Flat Window
(First Choice)
Figure 20. Shape of windows.
Recommended Plastic Materials:
Material #
Lexan 141
Lexan 920A
Lexan 940A
Note: 920A and 940A are more flame retardant than 141.
Light Transmission
88%
85%
85%
Curved Front and Back
(Second Choice)
Shape of the Window
From an optics standpoint, the
window should be flat. This
ensures that the window will not
alter either the radiation pattern
of the LED, or the receive pattern
of the photodiode.
If the window must be curved for
mechanical or industrial design
reasons, place the same curve on
the back side of the window that
has an identical radius as the
front side. While this will not
completely eliminate the lens
effect of the front curved surface,
it will significantly reduce the
effects. The amount of change in
Haze
1%
1%
1%
Refractive Index
1.586
1.586
1.586
Curved Front, Flat Back
(Do Not Use)
the radiation pattern is depen-
dent upon the material chosen
for the window, the radius of the
front and back curves, and the
distance from the back surface to
the transceiver. Once these items
are known, a lens design can be
made which will eliminate the
effect of the front surface curve.
The following drawings show the
effects of a curved window on the
radiation pattern. In all cases,
the center thickness of the
window is 1.5 mm, the window is
made of polycarbonate plastic,
and the distance from the
transceiver to the back surface of
the window is 3 mm.