AVAGO ASDL-3212

ASDL-3212
IrDA Data Compliant Low Power 1.152 Mbit/s Infrared Transceiver
Data Sheet
Description
General Features
The ASDL-3212 is a new generation ultra small low cost
infrared transceiver module which is compliance to IrDA
Physical Layers specifications version 1.4 low power
from 9.6Kbits/s to 1.152Mbit/s (MIR) with extended link
distance. It is IEC825-Class 1 eye safe and designed for
very low power consumption which is ideal for battery
operated handheld devices. ASDL-3212 features lower
pin count through integrated input-output function for
interfacing with low voltage 1.5V
• Operating temperature from -25°C ~ 85°C
- Critical parameters are guaranteed over
temperature and supply voltage
• Vcc Supply 2.4 to 3.6 V
• Interface to Various Super I/O and Controller Devices
- Support Integrated Input/Output Interface Voltage
of 1.5 V
• Miniature Package
- Height : 1.64 mm
- Width : 7.00mm
- Depth : 2.73mm
• Moisture Level 3
• No Programming required
• LED Stuck-High Protection
• High EMI Performance
• Designed to Accommodate Light Loss with Cosmetic
Windows
• IEC 825-Class 1 Eye Safe
Applications
• Mobile data communication
- Mobile Phones
- PDAs
- Digital Still Cameras
- Printer
- Handy Terminals
- Industrial and Medical Instrument
Application Support Information
The Application Engineering Group is available to assist
you with the application design associated with ASDL3212 infrared transceiver module. You can contact them
through your local sales representatives for additional
details.
IrDA Features
• Fully Compliant to IrDA 1.4 Physical Layer Low Power
Specifications from 9.6 kbit/s to 1.15 Mbit/s
- Typical Link Distance > 50cm
• Complete shutdown
• Low Power Consumption
- Low shutdown current
- Low idle current
Order Information
Part Number
Packaging Type
Package
Quantity
ASDL-3212-021
Tape and Reel
Front Option
2500
Marking Information
The unit is marked with ‘.PYWWLL’
P
= Product code
Y
= 1 digit numeric code for year
WW = 2 digits numeric code for work week
= 2 digits hexadecimal code for lot information
Vcc
CX2
GnD
CX1
Low
Pass
Filter
PreAmp
3
6
Quantizer
RXD
Tri-State
CMOS buffer
5
PostAmp
LL
Ambient DC Cancellation
VLED
R1
SD
4
Regulated
Voltage
Supply
AGC
LEDA
1
CX3
Buffer
2
Stuck One
Protection
r
TxD Buffe
TXD
ASDL-3212 Transceiver Module
Figure 1. Functional Block Diagram
PD
Recommended Application Circuit Components
Recommended Value
R1
Note
2.7Ω ± 5%,0.25 watt for 2.4 ≤ VLED < 2.6
3.3Ω ± 5%,0.25 watt for 2.6 ≤ VLED < 2.8
3.9Ω ± 5%,0.25 watt for 2.8 ≤ VLED < 3.0
4.7Ω ± 5%,0.25 watt for 3.0 ≤ VLED < 3.3
5.6Ω ± 5%,0.25 watt for 3.3 ≤ VLED < 3.5
6.8Ω ± 5%,0.25 watt for 3.5 ≤ VLED < 3.8
8.2Ω ± 5%,0.25 watt for 3.8 ≤ VLED < 4.2
10Ω ± 5%,0.25 watt for 4.2 ≤ VLED < 4.7
12Ω ± 5%,0.25 watt for 4.7 ≤ VLED < 5.0
CX2
100 nF, ± 20%, X7R Ceramic
7
CX1, CX3
6.8 mF, ± 20%, Tantalum
7
Note:
7. CX1 & CX2 must be placed within 0.7cm of ASDL-3212 to obtain
optimum noise immunity
I/O Pins Configuration Table
Pin
Symbol
Description
1
LEDA
LED Anode
I/O Type
Notes
2
TxD
IrDA transmitter data input.
Input, Active High
Note 2
3
RxD
IrDA receive data
Output, Active Low
Note 3
4
SD
Shutdown
Input, Active High
Note 4
5
Vcc
Supply Voltage
Note 5
6
GND
Ground
Note 6
Rear View
Note 1
6
5
4
3
2
1
Figure 2. Pin out
Note:
1. Tied through external resistor, R1, to Vled. Refer to the table below for recommended series resistor value.
2. This pin is used to transmit serial data when SD pin is low. If held high for longer than 50 ms, the LED is turned off. Do NOT float this pin.
3. This pin is capable of driving a standard CMOS or TTL load. No external pull-up or pull-down resistor is required. The pin is in tri-state when the
transceiver is in shutdown mode
4. Complete shutdown of IC and PIN diode. Do NOT float this pin.
5. Regulated, 2.4V to 3.6V
6. Connect to system ground.
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.
Absolute Maximum Ratings
Parameter
Symbol
Min.
Max.
Units
Storage Temperature
TS
-40
+100
°C
Junction Temperature
TJ
+100
°C
Operating Temperature
TA
-25
+85
°C
LED Anode Voltage
VLEDA
0
6
V
Supply Voltage
VCC
0
6
V
Input Voltage : TXD, SD/Mode
VI
0
6
V
Output Voltage : RXD
VO
0
6
V
Peak LED Current
ILED (PK)
300
mA
DC LED Current
ILED (DC)
60
mA
Conditions
Ref
≤ 20% duty cycle, ≤ 217ns pulse width
Fig. 5
Fig. 6
Recommended Operating Conditions
Parameter
Symbol
Min.
Operating Temperature
TA
Supply Voltage
Logic Input Voltage for TXD, SD/Mode
Receiver Input Irradiance
Logic High
Logic Low
LED (Logic High) Current Pulse
Amplitude
Receiver Data Rate
Ambient Light
Typ.
Max.
Units
-25
+85
°C
VCC
2.4
3.6
V
VIH
1.3
1.8
V
VIL
0
0.5
V
EIH
0.0090
500
mW/cm2
0.0225
500
EIL
0.3
ILEDA
250
0.0096
1.152
Conditions
For in-band signals≤ 115.2kbit/s [8]
0.576 Mbit/s ≤ in-band signals ≤1.152
Mbit/s [8]
mW/cm2
For in-band signals [8]
mA
VLED = 3.0V, RLED = 4.7W,
VI(TxD) ≥ VIH
Mbit/s
See IrDA Serial Infrared Physical Layer
Link Specification, Appendix A for
ambient levels
Note : [8] An in-band optical signal is a pulse/sequence where the peak wavelength, lp, is defined as 850 ≤ mp ≤ 900 nm, and the pulse
characteristics are compliant with the IrDA Serial Infrared Physical Layer Link Specification v1.4.
Electrical and Optical Specifications
Specifications (Min. & Max. values) hold over the recommended operating conditions unless otherwise noted. Unspecified test conditions may be anywhere in their operating range. All typical values (Typ.) are at 25°C and Vcc set to 3.0V
unless otherwise noted.
Receiver
Parameter
Symbol
Min.
Viewing Angle
2q1/2
30
Peak Sensitivity Wavelength
lP
RxD_IrDA Output Voltage
Typ.
Max.
Units
Conditions
°
875
nm
Logic High
VOH
1.3
1.8
V
Logic Low
VOL
0
0.4
V
IOH = -100 mA, EI ≤ 0.3 mW/cm2
RxD_IrDA Pulse Width (SIR) [9, 10]
tRPW(SIR)
1.5
ms
q1/2 ≤ 15°, CL=9pF, EI = 10 mW/cm2
RxD_IrDA Pulse Width (MIR) [9, 11]
tRPW(MIR)
250
ns
q1/2 ≤ 15°, CL=9pF, EI = 10 mW/cm2
RxD_IrDA Rise & Fall Times
tr, tf
60
ns
CL=9pF
Receiver Latency Time [12]
tL
120
ms
EI = 9.0 mW/cm2
Receiver Wake Up Time [13]
tRW
200
ms
EI = 10 mW/cm2
Max.
Units
Conditions
mW/sr
ILEDA = 250mA,
q1/2 ≤ 15°, VI (TxD) ≤ VIH,
Infrared (IR) Transmitter
Parameter
Symbol
Min.
Typ.
IR Radiant Intensity
IEH
9
80
IR Viewing Angle
2q1/2
30
lP
IR Peak Wavelength
TxD_IrDA Logic Levels
TxD_IrDA Input Current
60
870
°
nm
High
VIH
1.3
1.8
V
Low
VIL
0
0.5
V
High
IH
10
mA
VI ≥ VIH
Low
IL
10
mA
0 ≤ VI ≤ VIL
Wake Up Time [14]
tTW
200
ns
Maximum Optical Pulse Width [15]
tPW(Max)
70
ms
TXD Pulse Width (SIR)
tPW(SIR)
1.6
ms
tPW (TXD) =1.6ms at 115.2 kbit/s
TXD Pulse Width (MIR)
tPW(MIR)
217
ns
tPW (TXD) =217ns at 1.152 Mbit/s
TxD Rise & Fall Times (Optical)
tr, tf
ns
ns
tPW(TXD) =1.6ms at 115.2 kbit/s
tPW(TXD) =217ns at 1.15 Mbit/s
IR LED Anode On-State Voltage
VON (LEDA)
V
ILEDA = 250mA,
VI(TxD) ≥ VIH
600
40
2.0
Transceiver
Parameters
Input Current
Supply Current
Symbol
Min.
Typ.
Max.
Units
Conditions
High
IH
1
mA
VI ≥ VIH
Low
IL
1
mA
0 ≤ VI ≤ VIL
Shutdown
ICC1
1
mA
VSD > VCC-1.3, TA=25°C, no DC ambient
Idle (Standby)
ICC5
570
mA
VI(TxD) ≤ VIL, EI=0
445
Note:
[9] An in-band optical signal is a pulse/sequence where the peak wavelength, lP, is defined as 850 nm ≤ lP ≤ 900 nm, and the pulse characteristics
are compliant with the IrDA Serial Infrared Physical Layer Link Specification version 1.4.
[10] For in-band signals 115.2 kbit/s where 9 mW/cm2 ≤ EI ≤ 500 mW/cm2.
[11] For in-band signals 1.152 Mbit/s where 22 mW/cm2 ≤ EI ≤ 500 mW/cm2.
[12] Latency is defined as the time from the last TxD light output pulse until the receiver has recovered full sensitivity.
[13] Receiver Wake Up Time is measured from Vcc power ON to valid RxD output.
[14] Transmitter Wake Up Time is measured from Vcc power ON to valid light output in response to a TxD pulse.
[15] The Max Optical PW is defined as the maximum time which the IR LED will turn on, this, is to prevent the long Turn On time for the IR LED.
2.20
120
2.10
100
Radiant Intensity (mW/sr)
VLED_A (V)
2.00
1.90
1.80
1.70
1.60
1.50
1.40
000.0E+0
50.0E-3
80
60
40
20
0
000.0E+0
100.0E-3 150.0E-3 200.0E-3 250.0E-3 300.0E-3 350.0E-3
50.0E-3
100.0E-3 150.0E-3 200.0E-3 250.0E-3 300.0E-3 350.0E-3
ILED (A)
ILED (A)
Figure 3. VLED_A vs. ILED
Max. Permissible Peak LED Current
I LED(DC) , Maximum DC LED Current - mA
350
ILED(PK) Maximum Peak LED Current - mA
Figure 4. Radiant Intensity vs ILED
300
250
200
150
100
50
0
-40
-20
0
20
40
60
TA - Ambient Temperature - oC
80
Figure 5. Maximum Peak LED current vs. ambient temperature. Derated
based on TJMAX = 100°C.
100
Max. Permissible DC LED Current
70
60
50
40
Rθja = 400degC/W
30
20
10
0
-40
-20
0
20
40
60
TA - Ambient Temperature - oC
80
100
Figure 6 Maximum DC LED current vs. ambient temperature. Derated based
on TJMAX = 100°C.
ASDL-3212 (Option -021) Package Dimensions
Figure 7. Package Dimension for ASDL-3212-021
ASDL-3212 (Option -021) Tape & Reel Dimensions
4.0 ± 0.1
Unit: mm
∅ 1.5
1.75 ± 0.1
2.0 ± 0.1
+0.1
0
POLARITY
Pin 6: GND
7.5 ± 0.1
16.0 ± 0.2
Pin 1: LEDA
0.3 ± 0.05
7.4 ± 0.1
2.7 ± 0.1
1.85 ± 0.1
8.0 ± 0.1
Progressive Direction
Empty
Parts Mounted
Leader
(400mm min)
(40mm min)
Empty
(40mm min)
Option #
021
"B"
"C"
Quantity
330
80
2500
Unit: mm
Detail A
2.0 ± 0.5
B
C
∅ 13.0 ± 0.5
R1.0
LABEL
21 ± 0.8
Detail A
16.4
+2
0
2.0 ± 0.5
Figure 8. Tape and Reel dimensions
Moisture Proof Packaging
ASDL-3212 options are shipped in moisture proof
package. Once opened, moisture absorption begins.
This part is compliant to JEDEC Level 3.
Units in A Sealed
Mositure-Proof
Package
Package Is
Opened (Unsealed)
Environment
less than 30 deg C, and
less than 60% RH ?
Yes
Yes
No Baking
Is Necessary
Package Is
Opened less
than 168 hours ?
No
Perform Recommended
Baking Conditions
No
Figure 9. Baking Conditions Chart
Recommended Storage Conditions
Baking Conditions
If the parts are not stored in dry conditions, they must be
baked before reflow to prevent damage to the parts.
10°C to 30°C
Relative Humidity
below 60% RH
Package
Temp
Time
In reels
60 °C
≥ 48hours
Time from unsealing to soldering
≥ 4hours
After removal from the bag, the parts should be soldered
within 7 days if stored at the recommended storage conditions. If times longer than 7 days are needed, the parts
In bulk
100 °C
Baking should only be done once.
Storage Temperature
Recommended Reflow Profile
MAX 260C
T - TEMP ERATURE (°C)
255
R3
230
220
200
180
R2
60 s e c
MAX
Ab o ve 220 C
160
R1
120
R4
R5
80
25
0
50
P1
HEAT
UP
100
P2
S OLDER P AS TE DRY
150
200
P3
S OLDER
REFLOW
250
P4
COOL DOWN
300
t-TIME
(S ECONDS )
Process Zone
Symbol
DT
Maximum DT/Dtime
Heat Up
P1, R1
25°C to 160°C
3°C/s
Solder Paste Dry
P2, R2
160°C to 200°C
0.5°C/s
Solder Reflow
P3, R3
P3, R4
200°C to 255°C (260°C at 10 seconds max)
255°C to 200°C
4°C/s
-6°C/s
Cool Down
P4, R5
200°C to 25°C
-6°C/s
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 DT/Dtime temperature change rates. The DT/Dtime 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 ASDL-3212 castellation 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 3°C per second to allow for
even heating of both the PC board and ASDL-3212 castellations.
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).
10
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 intermetallic 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 ASDL-3212 castellations to change dimensions
evenly, putting minimal stresses on the ASDL-3212 transceiver.
Appendix A: ASDL-3212 (Option -021) SMT Assembly Application Note
Solder Pad, Mask and Metal Stencil
Metal Stencil
for Solder
Paste Printing
Stencil
Aperture
Aperture As Per
Land Dimensions
t
Land
Pattern
w
l
Solder
Mask
PCBA
Figure A1. Stencil and PCBA
Recommended land pattern
Figure A3. Solder stencil aperture
Stencil thickness,
t (mm)
Aperture size (mm)
Length, l
Width, w
0.127mm
1.75 +/- 0.05
0.55 +/- 0.05
0.110mm
2.40 +/- 0.05
0.55 +/- 0.05
Adjacent Land Keepout and Solder Mask Areas
CL
Adjacent land keepout 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 0.2mm. It is recommended that two fiducially crosses be placed at mid length of the pads for
unit alignment.
Mounting
Center
0.10
0.775
j
1.75
fiducial
0.60
h
1.425
k
2.375
Unit: mm
0.95
Pitch
Figure A2. Land Pattern
Units: mm
Recommended Metal Solder Stencil Aperture
It is recommended that only a 0.11mm (0.004 inch) or
a 0.127mm (0.005 inch) 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. Compared to
0.127mm stencil thickness 0.11mm stencil thickness has
longer length in land pattern. It is extended outwardly
from transceiver to capture more solder paste volume.
See figure 3.
11
l
Solder mask
Dimension
mm
h
0.2
l
3.0
k
3.0
j
8.6
Note: Wet/Liquid Photo-imaginable solder resist/mask is recommended.
Figure A4. Adjacent Land Keepout and solder mask areas
Appendix B: PCB Layout Suggestion
The ASDL-3212 is a shieldless part and hence does not
contain a shield trace unlike the other transceivers. The
effects of EMI and power supply noise can potentially
reduce the sensitivity of the receiver, resulting in reduced
link distance. The following PCB layout guidelines should
be followed to obtain a good PSRR and EM immunity
resulting in good electrical performance. Things to note:
The area underneath the module at the second layer, and
3cm in all direction around the module is defined as the
critical ground plane zone. The ground plane should be
maximized in this zone. The layout below is based on a
2-layer PCB.
1. The ground plane should be continuous under the
part.
2. VLED and Vcc can be connected to either unfiltered
or unregulated power supply. If VLED and Vcc share
the same power supply, CX3 need not be used. The
connections for CX1 and CX2 should be connected
before the current limiting resistor R1.
3. CX2 is generally a ceramic capacitor of low inductance
providing a wide frequency response while CX1 and
CX3 are tantalum capacitor of big volume and fast
frequency response. The use of a tantalum capacitor
is more critical on the VLED line, which carries a high
current.
4. Preferably a multi-layered board should be used
to provide sufficient ground plane. Use the layer
underneath and near the transceiver module as Vcc,
and sandwich that layer between ground connected
board layers. The diagrams below demonstrate an
example of a 4-layer board :
Top layer
Connect the module ground pin to
bottom ground layer
Layer 2
Critical ground plane zone. Do not connect
directly to the module ground pin
Layer 3
Keep data bus away from critical ground
plane zone
Bottom layer (GND)
12
Top Layer Bottom Layer
Appendix C: General Application Guide for the ASDL-3212 Infrared IrDA® Compliant 1.15Mb/s Transceiver
Description
Selection of Resistor R1
The ASDL-3212 is a low-cost and ultra small infrared
transceiver module that provides the interface between
logic and infrared (IR) signals for through air, serial, half
duplex IR data link. The device 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 9.6kb/s to 1.15Mb/s. The design of
ASDL-3212 also includes the following unique features:
Resistor R1 should be selected to provide the appropriate peak pulse LED current at different ranges of Vcc as
shown under “Recommended Application Circuit Components”.
Interface to the Recommended I/O chip
• Low passive component count;
The ASDL-3212’s TXD data input is buffered to allow
for CMOS drive levels. No peaking circuit or capacitor
is required. Data rate from 9.6kb/s up to 1.15Mb/s is
available at RXD pin.
• Shutdown mode for low power consumption
requirement;
Figures C1 and C2 show how ASDL-3212 fits into a mobile
phone and PDA platform respectively.
• Direct interface with Super I/O logic circuit.
STN/TFT LCD Panel
LCD Control
Touch Panel
A/D
Key Pad
Peripherial
interface PWM
LCD Backlight Contrast
*ASDL 3212
Mobile Application
chipset
Memory Expansion
Logic Bus Driver
ROM
FLASH
SDRAM
Figure C1. Mobile Application Platform
13
IrDA
interface
AC97
sound
PCM Sound
Baseband I2S
controller
Audio Input
Memory I/F
Power Management
Antenna
CoColor
Display
LCD Data/Timing
Control
Wired
Connectivity
USB Controller
PDA Application Chipset
McBSP
Configuration
EEPROM
LCD
Interface
External Memory Interface
Flash/
ROM/DRAM
OS/Apps
Peripheral Interface
*ASDL-3212
Antenna
USB
Reset
To Battery
Fuel Gauge
Figure C2. PDA Platform
The link distance testing was done using typical ASDL3212 units with SMC’s FDC37C669 and FDC37N769 Super
I/O controllers. An IR link distance of up to 50 cm was
demonstrated.
14
Key Pad
Camera
Smart Card
MMC SD
Stereo
Audio
Stereo
Speaker
Stereo
Headphone
Microphone
Touch
Screen
Controller
Appendix D: Window Design for ASDL-3212
Window Dimension
OPAQUE MATERIAL
IR Transparent Window
Y
IR Transparent Window
OPAQUE MATERIAL
X
K
Z
A
D
Figure D1. Window Design for ASDL-3212
To ensure IrDA compliance, some constraints on the
height and width of the window exist. The minimum
dimensions ensure that the IrDA cones angles are met
without vignetting. The maximum dimensions minimize
the effects of stray light. The minimum size corresponds
to a cone angle of 300 and the maximum size corresponds to a cone angle of 600.
In figure D1, X is the width of the window, Y is the height
of the window and Z is the distance from the ASDL-3212
to the back of the window. The distance from the center
of the LED lens to the center of the photodiode lens, K,
is 5.1mm. The equations for computing the window dimensions are as follows:
X = K + 2*(Z+D)*tanA
Y = 2*(Z+D)*tanA
15
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 ASDL-3212, D, is
4.32mm. ‘A’ is the required half angle for viewing. For IrDA
compliance, the minimum is 150 and the maximum is
300. Assuming the thickness of the window to be negligible, the equations result in the following table and
figures:
Module Depth
The recommended minimum aperture width and height
is based on the assumption that the center of the window
and the center of the module are the same. It is recommended that the tolerance for assembly be considered
as well. The minimum window size which will take into
account of the assembly tolerance is defined as:
Aperture Width (x, mm)
Aperture height (y, mm)
(z) mm
Max
min
Max
Min
0
10.09
7.42
4.99
2.32
1
11.24
7.95
6.14
2.85
2
12.40
8.49
7.30
3.39
3
13.55
9.02
8.45
3.92
4
14.71
9.56
9.61
4.46
5
15.86
10.09
10.76
4.99
6
17.02
10.63
11.92
5.53
Window Material
7
18.17
11.17
13.07
6.07
8
19.33
11.70
14.23
6.60
9
20.48
12.24
15.38
7.14
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 885 nm.
The recommended plastic materials for use as a cosmetic
window are available from General Electric Plastics.
25
Y (min + assembly tolerance) = Ymin + 2*(assembly
tolerance) (Dimensions are in mm)
Xmax
Xmin
20
Aperture Width (x) mm
X (min + assembly tolerance) = Xmin + 2*(assembly
tolerance) (Dimensions are in mm)
Recommended Plastic Materials:
15
Material #
10
5
0
0
1
2
3
4
5
6
Module Depth (z) mm
7
8
9
Figure D2. Aperture Height (x) vs. Module Depth (z)
18
Aperture Height (Y) mm
14
12
10
8
6
4
2
0
0
1
2
3
4
5
6
Module Depth (z) mm
Figure D3. Aperture Height (y) vs. Module Depth (z)
16
Refractive Index
Lexan 141
88%
1%
1.586
Lexan 920A
85%
1%
1.586
Lexan 940A
85%
1%
1.586
Note: 920A and 940A are more flame retardant than 141.
Recommended Dye: Violet #21051 (IR transmissant above
625mm)
Shape of the Window
Ymax
Ymin
16
Haze
7
8
9
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 backside 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.
Flat Window, (First Choice)
Curved Front and Back, (Second Choice)
For product information and a complete list of distributors, please go to our web site:
Curved Front, Flat Back, (Do not use)
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 © 2007 Avago Technologies Limited. All rights reserved.
AV02-0055EN - January 31, 2007