ASDL-3007 IrDA Data Compliant Low Power 115.2 Kbit/s with Remote Control Infrared Transceiver Data Sheet Description Features The ASDL-3007 is a new generation ultra-low profile enhanced infrared (IR) transceiver module that provides the capability of (1) interface between logic and IR signals for through-air, serial, half-duplex IR data link, and (2) IR remote control transmission for universal remote control applications. The ASDL-3007 can be used for IrDA as well as remote control application without the need of any additional external components for multiplexing. General Features The ASDL-3007 is fully compliant to IrDA Physical Layer specification version 1.4 low power from 9.6 kbit/s to 115.2 kbit/s (SIR) and IEC825 Class 1 eye safety standards. • Operating temperature from -25°C to +85°C - Critical parameters are guaranteed over temperature and supply voltage • Vcc Supply 2.4 to 3.6V • Miniature Package - Height : 1.60 mm - Width : 7.00 mm - Depth : 2.80 mm • Moisture Level 3 ASDL-3007 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. It is also designed especially for battery operated mobile devices such as PDAs and mobile phones that require low power consumption. • Integrated remote control LED driver Applications • Lead Free and ROHS Compliant • Mobile data communication and universal remote control - Mobile Phones - PDAs - Printers - Industrial and Medical Instrument IrDA Features • LED Stuck-High Protection • High EMI performance without shield • Designed to Accommodate Light Loss with Cosmetic Windows • IEC 825-Class 1 Eye Safe • Fully Compliant to IrDA 1.4 Physical Layer Low Power Specifications from 9.6 kbit/s to 115.2 kbit/s • Link distance up to 50cm typically • Complete shutdown • Low Power Consumption - Low shutdown current - Low idle current Remote Control Features • Wide angle and high radiant intensity • Spectrally suited to remote control transmission function • Typical link distance up to 8 meter Figure 1. Functional Block Diagram of ASDL-3007 8 7 6 5 4 3 Figure 2. Pin out for ASDL-3007 2 1 Application Support Information Marking Information The Application Engineering Group is available to assist you with the application design associated with ASDL3007 infrared transceiver module. You can contact them through your local sales representatives for additional details. The unit is marked with ‘PYWWLL’ on the back of the PCB for front option without shield. P = Product Code Y = Year WW = Work Week Order Information Part Number Packaging Type Package Quantity ASDL-3007-021 Tape and Reel Front Option 2500 LL = Lot Number I/O Pins Configuration Table Pin Symbol Description I/O Type Notes 1 LEDA LED Anode 2 SD Shutdown Input. Active High Note 2 3 TxD_IR IrDA transmitter data input. Input. Active High Note 3 4 RxD IrDA receive data Output. Active Low Note 4 5 Vcc Supply Voltage 6 TxD_RC RC transmitter data input. 7 NC 8 GND Note 1 Note 5 Input. Active High Note 6 Note 7 Ground Note 8 Notes: 1. Tied through external resistor, R1, to Vled. Refer to the table below for recommended series resistor value. 2. Complete shutdown of IC and PIN diode. The pin is used for setting receiver bandwidth and RC drive programming mode. Refer to section on “Bandwidth Selection Timing” and “Remote Control Drive Modes” for more information. Do NOT float this pin. 3. 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. 4. 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. 5. Regulated, 2.4V to 3.6V 6. Logic high turns on the RC LED. If held high longer than 50 ms, the RC LED is turned off. Do NOT float the pin. 7. NC. 8. Connect to system ground. CAUTIONS: The CMOS 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 Recommended Application Circuit Components Component Recommended Value Note R1 2.7 ohm ±5%, 0.25W for 2.4V≤ Vled≤2.7V 3.9 ohm ±5%, 0.25W for 2.7V≤ Vled≤3.0V 5.6 ohm ±5%, 0.25W for 3.0V≤ Vled≤3.3V 9.1 ohm ±5%, 0.25W for 3.3V≤ Vled≤4.2V R2 4.7 ohm ±5% 2 CX1 100 nF, ± 20%, X7R Ceramic 1 CX2,CX3 4.7mF, ± 20%, Tantalum 1 Notes : 1. CX1, CX2 must be placed within 0.7cm of ASDL-3007 to obtain optimum noise immunity 2. To reduce noise at VCC. Absolute Maximum Ratings For implementations where case to ambient thermal resistance is ≤ 50°C/W. Parameter Symbol Min. Max. Units Storage Temperature TS -40 +100 °C Operating Temperature TA -25 +85 °C LED Anode Voltage VLEDA 0 6.5 V Supply Voltage VCC 0 6.5 V Input Voltage : TXD VTXD 0 Vcc V Input Voltage : SD/Mode VSD 0 Vcc V Output Voltage : RXD VO 0 Vcc V DC LED Transmit Current ILED (DC) 32 mA Peak Transmit Current (RC) ILED (PK)_RC 1 A ≤ 8% duty cycle, ≤ 90 ms pulse width 1 Peak Transmit Current (IrDA) ILED (PK)_IR 0.5 A ≤ 20% duty cycle, ≤ 90 ms pulse width 2 Notes: 1. This peak current is specified for RC mode 2. This peak current is specified for IrDA mode Conditions Notes VledA < Vcc + 4V Recommended Operating Conditions Parameter Symbol Min. Operating Temperature TA Supply Voltage VCC LED Anode Voltage VLEDA Logic Input Voltage for TXD IR Logic Input Voltage for TXD RC Logic Input Voltage for SD Receiver Input Irradiance Typ. Max. Units -25 +85 °C 2.4 3.6 V 5.5 V VIH-IR Vcc-0.5 Vcc V Logic Low VIL-IR 0 0.4 V Logic High VIH-RC Vcc-0.5 Vcc V Logic Low VIL-RC 0 0.4 V Logic High VIH-SD Vcc-0.5 Vcc V Logic Low VIL-SD 0 0.4 V Logic High EIH 0.0090 500 mW/cm2 For in-band signals ≤ 115.2kbit/s [3] Logic Low EIL 0.3 mW/cm2 For in-band signals [3] ILEDA 40 mA LED (Logic High) Current Pulse Amplitude (RC) ILEDA 150 mA 9.6 115.2 Ambient Light VledA < Vcc + 4V Logic High LED (Logic High) Current Pulse Amplitude (IR) Receiver Data Rate Conditions kbit/s See IrDA Serial Infrared Physical Layer Link Specification, Appendix A for ambient levels Note : [1] An in-band optical signal is a pulse/sequence where the peak wavelength, lp, is defined as 850 ≤ lp ≤ 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, Vcc set to 3.0V unless otherwise noted. Parameter Symbol Min. Viewing Angle 2q1/2 30 Peak Sensitivity Wavelength lP Typ. Max. Units Conditions Receiver RxD_IrDA Output Voltage ° 875 nm Logic High VOH Vcc-0.5 Vcc V Logic Low IOH = -200 mA, EI ≤ 0.3 mW/cm2 VOL 0 0.4 V RxD_IrDA Pulse Width (SIR) [2] tRPW(SIR) 1 4 ms q1/2 ≤ 15°, CL=9pF RxD_IrDA Rise & Fall Times tr, tf ns CL=9pF Receiver Latency Time [3] tL 200 ms EI = 4.0 mW/cm2 Receiver Wake Up Time [4] tRW 200 ms EI = 10 mW/cm2 mW/sr ILEDA =40mA, TxD_IR ≥ VIH, TA = 25°C 60 Transmitter (IrDA Mode) IR Radiant Intensity IEH 4 IR Viewing Angle 2q1/2 30 lP IR Peak Wavelength TxD_IrDA Logic Levels TxD_IrDA Input Current 19 60 885 ° nm High VIH-IR Vcc-0.5 Vcc V Low VIL-IR 0 0.5 V High IH-IR 0.01 1 mA VI ≥ VIH Low IL-IR 2 10 mA 0 ≤ VI ≤ VIL Shutdown VSD ≥ VH-SD, IVLED 0.01 10 mA Wake Up Time [5] tTW 0.2 10 ms Maximum Optical Pulse Width [6] tPW(Max) 50 120 ms TXD Pulse Width (SIR) tPW(SIR) 1.6 TxD Rise & Fall Times (Optical) tr, tf LED Anode On-State Voltage VON (LEDA) RC Radiant Intensity IEH RC Viewing Angle 2q1/2 RC Peak Wavelength lP LED Current ms tPW(TXD_IR)=1.6ms at 115.2 kbit/s ns tPW(TXD_IR)=1.6ms at 115.2 kbit/s 2.8 V ILEDA=40mA, VI(TxD) ≥ VIH 70 mW/sr ILEDA = 150mA, q1/2 ≤ 15°, TxD_RC ≥ VIH, TA = 25 °C 600 Transmitter (Remote Control Mode) TxD_RC Logic Levels 60 885 ° nm High VIH Vcc-0.5 Low VIL 0 High IH 0.01 Low IL 2 Maximum Optical Pulse Width [8] tPW(Max) 60 ms LED Anode On-State Voltage VON (LEDA) 1.9 V TxD_RC Input Current 30 VCC V 0.5 V 1 mA VI ≥ VIH 10 mA 0 ≤ VI ≤ VIL ILEDA=150mA, VI(TxD) ≥ VIH Transceiver Parameters Symbol Min. Typ. Max. Logic Input Voltage for SD Logic High VIH-SD Vcc V 0 0.4 V Shutdown ICC1 0.03 Idle (Standby) ICC2 60 Active ICC3 350 Vcc-0.5 Logic Low Supply Current Units Conditions 1 mA Vsd ≥ 1.5V 80 mA VI(TxD) ≤ VIL, EI=0 mA VI(TxD) ≥ VIL, EI=10mW/cm2 VIL-SD Note: [2] For in-band signals 9.6 kbit/s to 115.2 kbit/s where 3.6 μW/cm2 ≤ EI ≤ 500 mW/cm2. [3] Latency is defined as the time from the last TxD_IrDA light output pulse until the receiver has recovered full sensitivity. [4] Receiver Wake Up Time is measured from Vcc power ON to valid RxD_IrDA output. [5] Transmitter Wake Up Time is measured from Vcc power ON to valid light output in response to a TxD_IrDA pulse. [6] The Optical PW is defined as the maximum time which the LED will turn on. This is to prevent the long turn on time for the LED. SIR Mode Typical ILED vs VLEDA at VCC=3.6V and Temp=25C 0.044352 SIR Mode Typical LOP vs ILED at VCC=3.6V and Temp=25C 22 20 18 LOP (mW/Sr) ILED (A) 0.042336 0.04032 0.038304 16 14 12 10 8 0.036288 2 2.2 2.4 2.6 2.8 3 0.02 3.2 0.025 RC Mode Typical ILED vs VLEDA at VCC=3.6V and Temp=25C 0.045 130 120 110 LOP (mW/Sr) 0.25 ILED (A) 0.04 RC Mode Typical LOP vs ILED at VCC=3.6V and Temp=25C 140 0.3 0.2 0.15 0.1 100 90 80 70 60 0.05 50 40 0 1.2 1.7 2.2 VLEDA (V) 0.035 ILED (A) VLEDA (V) 0.35 0.03 2.7 3.2 0.1 0.15 0.2 ILED (A) 0.25 0.3 Timing Diagram TXD “Stuck ON” Protection LED Optical Waveform RXD Output Waveform Receiver wakeup time waveform TXD wakeup time waveform Package Dimension Tape and Reel Dimensions Tape and Reel Dimensions (Cont.) 10 ASDL-3007 Moisture Proof Packaging All ASDL-3007 options are shipped in moisture proof package. Once opened, moisture absorption begins. This part is compliant to JEDEC Level 3. UNITS IN A SEALED MOISTURE-PROOF PACKAGE PACKAGE IS OPENED (UNSEALED) PARTS ARE NOT RECOMMENDED TO BE USED NO ENVIRONMENT LESS THAN 30 oC AND LESS THAN 60% RH YES PACKAGE IS OPENED LESS THAN 168 HOURS NO NO PACKAGE IS OPENED LESS THAN 15 DAYS YES PERFORM RECOMMENDED BAKING CONDITIONS 11 YES NO BAKING IS NECESSARY Baking Conditions Chart Baking Conditions Recommended Storage Conditions Storage Temperature 10 °C to 30 °C Relative Humidity Below 60% RH Time from unsealing to soldering After removal from the bag, the parts should be soldered within 7 days if stored at the recommended storage conditions. When MBB (Moisture Barrier Bag) is opened and the parts are exposed to the recommended storage conditions more than 7 days but less than 15 days the parts must be baked before reflow to prevent damage to the parts. Note: To use the parts that exposed for more than 15 days is not recommended. 12 If the parts are not stored per the recommended storage conditions they must be baked before reflow to prevent damage to the parts. Package Temp Time In reels 60 °C ≥ 48hours In bulk 100 °C ≥ 4hours Note: Baking should only be done once. Recommended Reflow Profile MAX 260°C T - TEMPERATURE (°C) 255 R3 230 217 200 180 R2 R4 60 sec to 90 sec Above 217°C 150 R5 R1 120 80 25 0 100 150 Process Zones Symbol DT Maximum DT/Dtime or Duration Heat Up P1, R1 25°C to 150°C 3°C/s Solder Paste Dry P2, R2 150°C to 200°C 100s to 180s Solder Reflow P3, R3 P3, R4 200°C to 260°C 260°C to 200°C 3°C/s -6°C/s Cool Down P4, R5 200°C to 25°C -6°C/s Time maintained above liquidus point , 217°C > 217°C 60s to 90s Peak Temperature 260°C - Time within 5°C of actual Peak Temperature - 20s to 40s Time 25°C to Peak Temperature 25°C to 260°C 8mins P1 HEAT UP 50 P2 SOLDER PASTE DRY 200 P3 SOLDER REFLOW 250 P4 COOL DOWN 300 t-TIME (SECONDS) 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 or duration. The DT/Dtime rates or duration 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-3007 pins are heated to a temperature of 150°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-3007 pins. Process zone P2 should be of sufficient time duration (100 to 180 seconds) to dry the solder paste. The temperature is raised to a level just below the liquidus point of the solder. Process zone P3 is the solder reflow zone. In zone P3, the temperature is quickly raised above the liquidus point of solder to 260°C (500°F) for optimum results. The dwell time above the liquidus point of solder should be between 60 and 90 seconds. This is to assure proper coalescing of the solder paste into liquid solder and the formation of good solder connections. Beyond the recommended dwell time 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 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 ASDL3007 pins to change dimensions evenly, putting minimal stresses on the ASDL-3007. It is recommended to perform reflow soldering no more than twice. 13 Appendix A: ASDL-3007 SMT Assembly Application Note Solder Pad, Mask and Metal Stencil Table 1 Land Pattern Solder Mask PCBA Figure A1. Stencil and PCBA Recommended land pattern + 1.7 0.35 0.50 0.425 Stencil thickness, t (mm) Length, l Width, w 0.127mm 1.7+/-0.05 0.5+/-0.05 Adjacent Land Keepout and Solder Mask Areas 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 0.25mm.It is recommended that two fiducially crosses be placed at mid length of the pads for unit alignment. Note: Wet/Liquid Photo-imaginable solder resist/mask is recommended MOUNTING CENTER 0.10 Aperture size (mm) Metal Stencil For Solder Paste Printing Stencil Aperture 0.75 FIDUCIAL Dimension mm h 0.25 l 1.5 k 3.0 j 8.0 0.85 j Figure A2. Recommended Land Pattern Recommended Metal solder Stencil Aperture h k It is recommended that a 0.127 mm (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 1 below the drawing for combinations of metal stencil aperture and metal stencil thickness that should be used. l SOLDER MASK Apertures As Per Land Dimensions t UNITS: mm Figure A4. Adjacent Land Keepout and Solder Mask Area l Figure A3. Solder stencil aperture 14 w Appendix B: PCB Layout Suggestion The ASDL-3007 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: 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. CX1 is generally a ceramic capacitor of low inductance providing a wide frequency response while CX2 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 : 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. 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) Top Layer 15 Bottom Layer Appendix C: General Application Guide for the ASDL-3007 Infrared IrDA® Compliant 115.2kb/s Transceiver Description Selection of Resistor R1 The ASDL-3007, a wide-voltage operating range infrared transceiver, is a low-cost and ultra 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 spectrally suited to universal remote control transmission function. It is fully compliant to IrDA 1.4 low power specification from 9.6kb/s to 115.2kb/s, and support most remote control codes. The design of ASDL-3007 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 on page 4 under “Recommended Application circuit components”. • Spectrally suited to transmission function; universal remote control • Low passive component count; • Shutdown mode for low power consumption requirement; Interface to the Recommended I/O chip The ASDL-3007’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 115.2kb/s is available at RXD pin. The TXD_RC, pin6, is used to select the remote control transmit mode. Alternatively, the TXD_IR, pin3, is used for infrared transmit selection. Figures C1 and C2 show how ASDL-3007 fits into a mobile phone and PDA platform respectively. Speaker Audio Interface DSP Core Microphone ASIC Controller Transceiver Mod/De-modulator RF Interface IR Microcontroller User Interface Figure C1. Mobile Application Platform RC IR LCD Panel RAM ROM CPU for embedded application Touch Panel PCMCIA Controller RS232C Driver Figure C2. PDA Platform 16 COM Port RC Remote Control Operation The ASDL-3007 is spectrally suited to universal remote control transmission function. Remote control applications are not governed by any standards, owing to which there are numerous remote codes in market. Each of those standards results in receiver modules with different sensitivities, depending on the carries frequencies and responsively to the incident light wavelength. nication commonly known as Infrared Communications Port (ICP). The remote control commands can be sent through one of the available General Purpose IO pins (GPIO). It is not recommended to turn on both IrDA data transmission and Remote control transmission simultaneously to prevent mixing and corruption of data. During IrDA data transmission, TxD_RC pin should be pull-down but not letting it floating. Same condition applied for Remote control transmission, which TxD_IR pin should not be left floating. Figure C3 illustrate a reference interfacing circuit to implement both IrDA and RC functionality using ASDL3007. The transceiver is directly interface with the microprocessor provided it has support for infrared commuVCC CX1 GND CX2 (5) V CC (8) GND (6) TXD_RC GPIO IR_RXD (4) RXD GPIO (2) SD IR_TXD 100Kohm (3) TXD_IR VLED R1 (7) NC (1) LEDA 100Kohm GND A SDL -3007 CX3 GND GND Figure C3. Reference design circuit for IrDA+RC transceiver 17 Appendix D: Window Design for ASDL-3007 Window Dimension 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. OPAQUE MATERIAL Aperture Width (x, mm) Max min 10.09 7.42 11.24 7.95 12.40 8.49 13.55 9.02 14.71 9.56 15.86 10.09 17.02 10.63 18.17 11.17 19.33 11.70 20.48 12.24 Module Depth (z) mm 0 1 2 3 4 5 6 7 8 9 IR Transparent Window Aperture Height (y, mm) Max Min 4.99 2.32 6.14 2.85 7.30 3.39 8.45 3.92 9.61 4.46 10.76 4.99 11.92 5.53 13.07 6.07 14.23 6.60 15.38 7.14 25 Y K Z X OPAQUE MATERIAL A Aperture Width (x) mm 20 IR Transparent Window 15 10 5 Xmax Xmin D 0 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-3007 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 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-3007, 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: 18 1 2 3 4 5 Module Depth (z) mm 6 7 8 9 Figure D2. Aperture Height (x) vs. Module Depth (z) 18 16 14 Aperture Height (Y) mm Figure D1. Window Design for ASDL-3007 0 12 10 8 6 4 Ymax Ymin 2 0 0 1 2 3 4 5 Module Depth (z) mm 6 7 8 9 Figure D3. Aperture Height (y) vs. Module Depth (z) 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 acount of the assembly tolerance is defined as: X (min + assembly tolerance) = Xmin + 2*(assembly tolerance) (Dimensions are in mm) Y (min + assembly tolerance) = Ymin + 2*(assembly tolerance) (Dimensions are in mm) Window Material Shape of the Window 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. 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. Recommended Plastic Materials: Material # Light Transmission Haze 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) 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. AV02-0454EN - June 21, 2007