HSDL-3203
Small Profile Package IrDA® Data Compliant
Low Power 115.2 kbit/s Infrared Transceiver
Data Sheet
Description
Features
The HSDL-3203 is a miniature low cost infrared transceiver module that provides the interface between
logic and infrared (IR) signals for through air, serial,
half-duplex IR data link. The module is compliant to
IrDA Physical Layer Specifications version 1.4 Low
Powerfrom 9.6 kbit/s to 115.2 kbit/s with
extended link distance and it is IEC 825-Class 1 eye
safe.
• Fully compliant to IrDA 1.4 low power specification
from 9.6 kbit/s to 115.2 kbit/s
The HSDL-3203 can be shutdown completely to
achieve very low power consumption. In the shutdown
mode, the PIN diode will be inactive and thus producing very little photocurrent even under very bright
ambient light. Such features are ideal for battery
operated handheld products.
• Low power operation at extended link distance of 50 cm
• Miniature package
— Height: 1.95 mm
— Width: 8.00 mm
— Depth: 3.10 mm
• Guaranteed temperature performance, –20 to +70˚C
— Critical parameters are guaranteed over
temperature and supply voltage
• Low power consumption
— Low shutdown current (10 nA typical)
— Complete shutdown of TXD, RXD, and PIN diode
• Withstands > 100 mVp-p power supply ripple typically
• VCC supply 2.7 to 3.6 volts
• Integrated EMI shield
• LED stuck-high protection
• Designed to accommodate light loss with cosmetic
windows
• IEC 825-Class 1 Eye Safe
• Lead-free and RoHS Compliant
Applications
• Mobile telecom
— Mobile phones
— Pagers
— Smart phone
• Data communication
— PDAs
— Portable printers
• Digital imaging
— Digital cameras
— Photo-imaging printers
• Electronic wallet, IrFM
Application Support
Information
Ordering Information
Part Number
HSDL-3203-021
The Application Engineering
group in Avago Technologies is
available to assist you with the
technical understanding associated with HSDL-3203 infrared
transceiver module. You can contact them through your local
Avago sales representative for
additional details.
VCC
R1
Packaging Type
Tape and Reel
Package
Front View
Quantity
2500
LED A 8
TXD 7
LED
DRIVER
VCC 6
VCC
C1
6.8 µF
RXD 5
SHIELD
GND 4
AGND 3
VCC
SD 2
RX PULSE
SHAPER
CX 1
C2
100 nF
8
Figure 1. Functional block diagram of HSDL-3203.
2
7
6
5
4
3
2
1
Figure 2. Rear view diagram with pin-out.
I/O Pin Configuration Table
Pin
1
2
3
4
5
Symbol
CX
SD
AGND
GND
RXD
I/O
I
I
I
I
O
Description
Pin bypass capacitor
Shutdown. Active high
Analog ground
Ground
Receiver data output. Active low
Note
1
2
2
3
6
VCC
I
Supply voltage
4
7
8
–
TXD
LED A
Shield
I
I
–
Transmitter data input. Active high
LED anode
EMI shield
5
6
7
Notes:
1. Complete shutdown TXD, RXD, and PIN diode.
2. Connect to system ground.
3. Output is active low pulse response when light pulse is seen.
4. Regulated, 2.7 to 3.6 volt.
5. Logic high turns on the LED. If held high longer than ∼50 µs, the LED is turned off
automatically. TXD must be driven either high or low. DO NOT leave the pin floating.
6. Tied through external resistor, R1, to regulate VCC from 2.7 to 3.6 volt.
7. Connect to system ground via a low inductance trace. For best performance, do not connect
to GND directly at the part.
Recommended Application Circuit Components
Component
R1
R1
C1
C2
Recommended Value
30 Ω, ± 1%, 0.125 Watt
5.6 Ω, ± 1%, 0.125 Watt
6.8 µF, ± 20%, Tantalum
100 nF, ± 20%, X7R Ceramic
Marking Information
The unit is marked with the
letters "A" and the datacode
"YWW" on the shield for front
options where Y is the last digit
of the year, and WW is the
workweek.
Note
8
9
10
Notes:
8. To obtain ILED of 50 mA for VLED of 3 V.
9. To obtain ILED of 250 mA for VLED of 3 V.
10. C1 must be placed within 0.7 cm of the HSDL-3203 to obtain optimum noise immunity.
Transceiver I/O Truth Table
Inputs
TXD
High
Low
Low
Don't Care
Light Input to Receiver
Don't Care
High
Low
Don't Care
SD
Low
Low
Low
High
Outputs
LED
On
Off
Off
Off
RXD
Not Valid
Low
High
High
Note
11, 12
Notes:
11. In-band IrDA signals and data rates ≤ 115.2 kbit/s.
12. RXD logic low is a pulsed response. The condition is maintained for a duration independent of pattern and strength of the incident intensity.
Caution: The BiCMOS inherent to the design of this component increases the component's susceptibility
to damage from electrostatic discharge (ESD). It is advised that normal static precautions be taken in
handling and assembly of this component to prevent damage and/or degradation, which may be
induced by ESD.
3
Absolute Maximum Ratings
For implementation where case to ambient thermal resistance is ≤ 50˚C/W.
Parameter
Symbol
Min.
Max.
Storage Temperature
TS
–40
100
Operating Temperature
TA
–25
85
DC LED Current
ILED (DC)
20
Peak LED Current
ILED (PK)
250
Units
˚C
˚C
mA
mA
LED Anode Voltage
Supply Voltage
Input Voltage TXD, SD
Output Voltage RXD
V
V
V
V
VLEDA
VCC
VI
VO
–0.5
0
0
–0.5
7
7
VCC + 0.5
VCC + 0.5
Conditions
≤ 90 µs Pulse Width
≤ 25% Duty Cycle
Recommended Operating Conditions
Parameter
Operating Temperature
Supply Voltage
Logic High Voltage TXD, SD
Logic Low Voltage TXD, SD
Logic High Receiver Input Irradiance
Logic Low Receiver Input Irradiance
LED Current Pulse Amplitude
Receiver Signal Rate
Symbol
TA
VCC
VIH
VIL
EIH
EIL
ILEDA
Min.
–25
2.7
2/3 VCC
0
0.0081
50
9.6
Max.
85
3.6
VCC
1/3 VCC
500
0.3
250
115.2
Units
˚C
V
V
V
mW/cm2
µW/cm2
mA
kbit/s
Conditions
Note
For in-band signals
For in-band signals
Guaranteed at 25˚C
13
13
Note:
13. An in-band optical signal is a pulse/sequence where the peak wavelength, λp, is defined as 850 nm ≤ λp ≤ 900 nm, and the pulse characteristics
are compliant with the IrDA Serial Infrared Physical Layer Link Specification.
4
Electrical and Optical Specifications
Specifications hold over the recommended operating conditions unless otherwise noted. Unspecified test conditions
can be anywhere in their operating range. All typical values are at 25˚C and 3.0 V unless otherwise noted.
Parameter
Symbol Min.
Typ. Max. Units
Conditions
Note
Receiver
RXD Output Voltage Logic Low VOL
0
0.4
V
IOL = 200 µA, for in-band EI
14
Logic High VOH
VCC
VCC V
IOH = 200 µA, for in-band
–0.2
EI ≤ 0.3 µW/cm2
Viewing Angle
2φ1/2
30
˚
Logic High Receiver Input
EIH
0.0081
500
mW/cm2 For in-band signals ≤ 115.2 kbit/s 13
Irradiance
Logic Low Receiver Input
EIL
0.3
µW/cm2 For in-band signals
13
Irradiance
Peak Sensitivity Wavelength
λp
880
nm
RXD Pulse Width
tpw
1.5
2.5 4.0
µs
14
RXD Rise and Fall Times
tr, tf
25
100
ns
tpw(EI) = 1.6 µs, CL = 10 pF
Receiver Latency Time
tL
25
50
µs
14
Receiver Wake Up Time
tW
50
100
µs
15
Transmitter
Radiant Intensity
EIH
4
8
28.8 mW/sr
ILEDA = 50 mA, TA = 25˚C,
θ1/2 ≤ 15˚
22.5
mW/sr
ILEDA = 250 mA, TA = 25˚C,
θ1/2 ≤ 15˚
Peak Wavelength
λp
875
nm
Spectral Line Half Width
∆λ1/2
35
nm
Viewing Angle
2θ1/2
30
60
˚
Optical Pulse Width
tpw
1.5
1.6 2
µs
tpw(TXD) = 1.6 µs
Optical Rise and Fall Times
tr (EI)
600
ns
tpw(TXD) = 1.6 µs
tf (EI)
Maximum Optical Pulse Width
tpw
20
50
µs
TXD pin stuck high
(max)
LED Anode ON State Voltage
VON
1.5
V
ILEDA = 50 mA,
(LEDA)
VIH (TXD) = 2.7 V
LED Anode OFF State Leakage
ILK
0.01 1.0
µA
VLEDA = VCC = 3.6 V,
(LEDA)
VI (TXD) ≤ 1/3 VCC
Transceiver
TXD and SD Input
Logic Low IL
–1
–0.01 1
µA
0 ≤ VI ≤ 1/3 VCC
Currents
Logic High IH
0.01 1
µA
VI ≥ 2/3 VCC
Supply Current
Shutdown ICCI
10
200
nA
VCC = 3.6 V, VSD ≥ VCC –0.5
Idle
ICC2
2.5 4
mA
VCC = 3.6 V, VI(TXD) ≤ 1/3 VCC,
EI = 0
Active
ICC3
2.6 5
mA
VCC = 3.6 V, VI(TXD)≤ 1/3 VCC
16
Receiver
Notes:
14. For in-band signals ≤ 115.2 kbit/s where 8.1 µW/cm2 ≤ EI ≤ 500 mW/cm2.
15. Wake up time is measured from SD pin HIGH to LOW transition or VCC power ON to valid RXD output.
16. Typical value is at EI = 10 mW/cm2, maximum value is at EI = 500 mW/cm2.
5
tpw
VOH
90%
50%
VOL
10%
tf
tr
Figure 3. RXD output waveform.
tpw
LED ON
90%
50%
10%
LED OFF
tr
tf
Figure 4. LED optical waveform.
TXD
LED
tpw (MAX.)
Figure 5. TXD ‘Stuck On’ protection waveform.
SD
SD
RX
LIGHT
TXD
RXD
TX
LIGHT
tRW
Figure 6. Receiver wakeup time waveform.
6
tTW
Figure 7. TXD wakeup time waveform.
VLED_A vs ILED_A,
TEMPERATURE = 25°C
RADIANT INTENSITY vs ILED_A,
TEMPERATURE = 25°C
2.2
35
2.0
30
VLED_A (V)
RADIANT INTENSITY (mW/sr)
40
25
20
15
1.8
1.6
1.4
10
1.2
5
0
000.0E+0
100.0E-3
200.0E-3
1.0
000.0E+0
300.0E-3
100.0E-3
200.0E-3
300.0E-3
ILED_A (A)
ILED_A (A)
Figure 9. VLED vs. LED current.
Figure 8. LOP vs. ILED.
Package Outline with Dimensions
MOUNTING
CENTER
4.0
1.025
CL
2.05
RECEIVER
EMITTER
1.95
0.96
2.55
;;;;
;;
0.35
0.65
0.80
COPLANARITY:
± 0.1 mm
2.85
4.0
8.0
3.1
CL
3.0
1.85
UNIT: mm
TOLERANCE: ± 0.2mm
8
7
6
5
4
3
2
3.325
P0.95 x 7 = 6.65
1
2
3
4
Figure 10. Package outline dimensions.
7
0.6
CX
SD
AGND
GND
5
6
7
8
RXD
VCC
TXD
LEDA
1
Tape and Reel Dimensions
UNIT: mm
4.0 ± 0.1
1.75 ± 0.1
+ 0.1
∅ 1.5 0
1.5 ± 0.1
POLARITY
PIN 8: LED A
7.5 ± 0.1
16.0 ± 0.2
8.4 ± 0.1
PIN 1: CX
3.4 ± 0.1
0.4 ± 0.05
8.0 ± 0.1
2.8 ± 0.1
PROGRESSIVE DIRECTION
EMPTY
PARTS MOUNTED
LEADER
(400 mm MIN.)
(40 mm MIN.)
EMPTY
(40 mm MIN.)
OPTION # "B" "C" QUANTITY
001
178
60
500
021
330
80
2500
UNIT: mm
DETAIL A
2.0 ± 0.5
B
C
∅ 13.0 ± 0.5
R 1.0
LABEL
21 ± 0.8
DETAIL A
2
16.4 + 0
2.0 ± 0.5
Figure 11. Tape and reel dimensions.
8
Moisture-Proof Packaging
All HSDL-3203 options are shipped in moisture-proof packaging. Once opened, moisture absorption begins.
UNITS IN A SEALED
MOISTURE-PROOF
PACKAGE
PACKAGE IS
OPENED (UNSEALED)
ENVIRONMENT
LESS THAN 25°C,
AND LESS THAN
60% RH?
YES
NO BAKING
IS NECESSARY
NO
PACKAGE IS
OPENED MORE
THAN 2 DAYS?
NO
YES
PERFORM RECOMMENDED
BAKING CONDITIONS
Figure 12. Baking conditions chart.
Baking Conditions
If the parts are not stored in dry
conditions, they must be baked
before reflow to prevent damage
to the parts.
Packaging
In Reels
In Bulk
Temp.
60˚C
100˚C
125˚C
150˚C
Time
≥ 48 hours
≥ 4 hours
≥ 2 hours
≥ 1 hour
Baking should only be done once.
9
Recommended Storage
Conditions
Storage Temp.
Relative Humidity
10˚C to 30˚C
Below 60% RH
Time from Unsealing to Soldering
After removal from the bag, the
parts should be soldered within
two days if stored at the recommended storage conditions. If
times longer than two days are
needed, the parts must be stored
in a dry box.
Reflow Profile
MAX. 260°C
T – TEMPERATURE – (°C)
255
R3
230
220
200
180
R4
R2
60 sec.
MAX.
ABOVE
220°C
160
R1
120
R5
80
25
0
50
100
150
200
250
300
t-TIME (SECONDS)
P1
HEAT
UP
P2
SOLDER PASTE DRY
P3
SOLDER
REFLOW
P4
COOL
DOWN
Figure 13. Reflow graph.
Process Zone
Heat Up
Solder Paste Dry
Solder Reflow
Cool Down
Symbol
P1, R1
P2, R2
P3, R3
P3, R4
P4, R5
The reflow profile is a straight
line representation of a nominal
temperature profile for a convective reflow solder process. The
temperature profile is divided
into four process zones, each
with different ∆T/∆time temperature change rates. The ∆T/∆time
rates are detailed in the above
table. The temperatures are
measured at the component to
printed circuit board connections.
In process zone P1, the PC board
and HSDL-3203 castellation I/O
pins are heated to a temperature
of 160°C to activate the flux in
the solder paste. The temperature
ramp up rate, R1, is limited to
4°C per second to allow for even
heating of both the PC board and
HSDL-3203 castellation I/O pins.
10
∆T
25˚C to 160˚C
160˚C to 200˚C
200˚C to 255˚C (260˚C at 10 seconds max.)
255˚C to 200˚C
200˚C to 25˚C
Process zone P2 should be of
sufficient time duration (60 to
120 seconds) to dry the solder
paste. The temperature is raised
to a level just below the liquidus
point of the solder, usually 200°C
(392°F).
Process zone P3 is the solder
reflow zone. In zone P3, the temperature is quickly raised above
the liquidus point of solder to
255°C (491°F) for optimum
results. The dwell time above the
liquidus point of solder should be
between 20 and 60 seconds. It
usually takes about 20 seconds to
assure proper coalescing of the
solder balls into liquid solder and
the formation of good solder
connections. Beyond a dwell
time of 60 seconds, the inter-
Maximum ∆T/∆time
4˚C/s
0.5˚C/s
4˚C/s
–6˚C/s
–6˚C/s
metallic growth within the solder
connections becomes excessive,
resulting in the formation of weak
and unreliable connections. The
temperature is then rapidly
reduced to a point below the
solidus temperature of the solder,
usually 200°C (392°F), to allow
the solder within the connections
to freeze solid.
Process zone P4 is the cool down
after solder freeze. The cool
down rate, R5, from the liquidus
point of the solder to 25°C (77°F)
should not exceed 6°C per second
maximum. This limitation is necessary to allow the PC board and
HSDL-3203 castellation I/O pins
to change dimensions evenly,
putting minimal stresses on the
HSDL-3203 transceiver.
Appendix A : SMT Assembly Application Note
1.0 Solder Pad, Mask and Metal Solder Stencil Aperture
METAL STENCIL
FOR SOLDER PASTE
PRINTING
STENCIL
APERTURE
LAND
PATTERN
SOLDER
MASK
PCBA
Figure 14. Stencil and PCBA.
1.1 Recommended Land Pattern
CL
SHIELD
SOLDER PAD
1.35
MOUNTING
CENTER
1.25
2.05
0.10
0.775
1.75
FIDUCIAL
0.60
0.475
1.425
UNIT: mm
2.375
3.325
Figure 15. Land pattern.
11
1.2 Recommended Metal Solder
Stencil Aperture
It is recommended that only a
0.152 mm (0.006 inches) or a
0.127 mm (0.005 inches) thick
stencil be used for solder paste
printing. This is to ensure adequate printed solder paste volume and no shorting. See the
table below the drawing for combinations of metal stencil aperture and metal stencil thickness
that should be used.
Aperture opening for shield pad
is 2.7 mm x 1.25 mm as per land
pattern.
Stencil Thickness, t (mm)
0.152 mm
0.127 mm
1.3 Adjacent Land Keepout and
Solder Mask Areas
Adjacent land keep-out is the
maximum space occupied by
the unit relative to the land pattern. There should be no other
SMD components within this
area.
The minimum solder resist strip
width required to avoid solder
bridging adjacent pads is
0.2 mm. It is recommended that
two fiducial crosses be placed at
mid-length of the pads for unit
alignment.
APERTURES AS PER
LAND DIMENSIONS
t
w
l
Figure 16. Solder stencil aperture.
Aperture Size (mm)
Length, l
Width, w
2.60 ± 0.05
0.55 ± 0.05
3.00 ± 0.05
0.55 ± 0.05
8.2
0.2
SOLDER MASK
Note: Wet/Liquid PhotoImageable solder resist/mask is
recommended.
3.0
UNITS: mm
Figure 17. Adjacent land keep-out and solder mask areas.
12
2.6
COMPONENT SIDE
Appendix B: PCB Layout
Suggestion
The following shows an example
of a PCB layout using option
#021 that would result in good
electrical and EMI performance.
Things to note:
1. The ground plane should be
continuous under the part, but
should not extend under the
shield trace.
C1
4. C1 and C3 are optional supply
filter capacitors; they may be
left out if a clean power supply is used.
CIRCUIT SIDE
5. VLED can be connected to
either unfiltered or unregulated power supply. If VLED
and VCC share the same power
supply and C1 is used, the
connection should be before
the C1 cap. In a noisy environment, supply rejection can
be enhanced by including C3
as well.
Figure 18. PCB layout suggestions.
13
SHIELD
SHUTDOWN
3. The AGND pin is connected to
the ground plane and not to
the shield tab.
SYSTEM
GROUND
RXD
VCC
TXD
C3
VLED
2. The shield trace is a wide, low
inductance trace back to the
system ground.
C2
R1
Appendix C: General Application
Guide for the HSDL-3203 Infrared
IrDA® Compliant 115.2 kb/s
Transceiver
Description
The HSDL-3203, a wide voltage
operating range infrared
transceiver, is a low-cost and
small form factor device that is
designed to address the mobile
computing market such as PDAs,
as well as small embedded mobile
products such as digital cameras
and cellular phones. It is fully
compliant to IrDA 1.4 low power
specification from 9.6 kb/s to
115.2 kb/s, and supports HP-SIR
and TV Remote modes. The
design of the HSDL-3203 also
includes the following unique
features:
• Low passive component count.
• Shutdown mode for low power
consumption requirement.
Selection of Resistor R1
Resistor R1 should be selected to
provide the appropriate peak
pulse LED current over different
ranges of VCC as shown in the
table below.
Recommended
R1
VCC
Intensity
Minimum peak
pulse LED current
30 Ω
5.6 Ω
3V
3V
8 mW/sr
34 mW/sr
50 mA
250 mA
Interface to Recommended I/O Chips
The HSDL-3203’s TXD data input
is buffered to allow for CMOS
drive levels. No peaking circuit or
capacitor is required.
Data rate from 9.6 kb/s up to
115.2 kb/s is available at the RXD
pin.
The block diagram below shows
ow the IR port fits into a mobile
phone and PDA platform.
SPEAKER
AUDIO INTERFACE
DSP CORE
MICROPHONE
ASIC
CONTROLLER
RF INTERFACE
TRANSCEIVER
MOD/
DE-MODULATOR
IR
MICROCONTROLLER
USER INTERFACE
MOBILE PHONE PLATFORM
Figure 19. IR layout in mobile phone platform.
14
HSDL-3203
LCD
PANEL
RAM
IR
CPU
FOR EMBEDDED
APPLICATION
ROM
PCMCIA
CONTROLLER
TOUCH
PANEL
HSDL-3203
RS232C
DRIVER
PDA PLATFORM
Figure 20. IR layout in PDA platform.
The link distance testing was
done using typical HSDL-3203
units with National
Semiconductor’s PC87109 3V
Super I/O controller and SMC’s
FDC37C669 and FDC37N769
Super I/O controllers. An IR link
distance of up to 100 cm was
demonstrated.
15
COM
PORT
Appendix D: Optical port
dimensions for HSDL-3203:
To ensure IrDA compliance, some
constraints on the height and
width of the window exist. The
minimum dimensions ensure that
the IrDA cone angles are met
without vignetting. The maximum
dimensions minimize the effects
of stray light. The minimum size
corresponds to a cone angle of
30˚ and the maximum size corresponds to a cone angle of 60˚.
In the figure below, X is the width
of the window, Y is the height of
the window, and Z is the distance
from the HSDL-3203 to the back
of the window. The distance from
the center of the LED lens to the
center of the photodiode lens, K,
is 5.1 mm. The equations for
computing the window dimensions are as follows:
X = K + 2*(Z + D)*tanA
Y = 2*(Z + D)*tanA
The above equations assume that
the thickness of the window is
negligible compared to the distance of the module from the
back of the window (Z). If they
are comparable, Z' replaces Z in
the above equation. Z' is defined
as:
Z' = Z + t/n
where ‘t’ is the thickness of the
window and ‘n’ is the refractive
index of the window material.
The depth of the LED image inside the HSDL-3203, D, is
3.17 mm. ‘A’ is the required half
angle for viewing. For IrDA compliance, the minimum is 15˚ and
the maximum is 30˚. Assuming
the thickness of the window to be
negligible, the equations result in
the following tables and graphs.
;;;;;;;;
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IR TRANSPARENT WINDOW
OPAQUE
MATERIAL
Z
X
IR TRANSPARENT
WINDOW
K
Z
A
D
16
OPAQUE
MATERIAL
Aperture Width (x, mm)
Max.
Min.
8.76
6.80
9.92
7.33
11.07
7.87
12.22
8.41
13.38
8.94
14.53
9.48
15.69
10.01
16.84
10.55
18.00
11.09
19.15
11.62
APERTURE WIDTH (X) vs MODULE DEPTH
APERTURE HEIGHT (Y) vs MODULE DEPTH
16
20
15
10
X MAX.
X MIN.
5
0
0
1
2
3
4
5
6
7
MODULE DEPTH (Z) – mm
17
Aperture Height (y, mm)
Max.
Min.
3.66
1.70
4.82
2.33
5.97
2.77
7.12
3.31
8.28
3.84
9.43
4.38
10.59
4.91
11.74
5.45
12.90
5.99
14.05
6.52
25
APERTURE HEIGHT (Y) – mm
APERTURE WIDTH (X) – mm
Module Depth
(z) mm
0
1
2
3
4
5
6
7
8
9
8
9
14
12
10
8
6
4
Y MAX.
Y MIN.
2
0
0
1
2
3
4
5
6
7
MODULE DEPTH (Z) – mm
8
9
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.
Recommended Plastic Materials:
Material
Number
Lexan 141L
Lexan 920A
Lexan 940A
Light
Transmission
88%
85%
85%
Haze
1%
1%
1%
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
the radiation pattern is dependent
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.
Refractive
Index
1.586
1.586
1.586
Note: 920A and 940A are more flame retardant than 141L.
Recommended Dye: Violet #21051 (IR transmissant above
625 nm).
Flat Window
(First Choice)
18
Curved Front and Back
(Second Choice)
Curved Front, Flat Back
(Do Not Use)
For product information and a complete list of distributors, please go to our website:
www.avagotech.com
Avago, Avago Technologies, and the A logo are trademarks of Avago Technologies, Limited in the United States and other countries.
Data subject to change. Copyright © 2006 Avago Technologies Pte. All rights reserved. Obsoletes 5988-8581EN
5989-2869EN May 28, 2006