HSDL-3002-007

HSDL-3002 IrDA® Data Compliant Low Power 115.2 kbit/s with Remote Control Transmission Infrared Transceiver Data Sheet Description The HSDL-3002 is a small form factor single enhanced infrared (IR) transceiver module that provides the combination of (1) interface between logic and IR signals for through-air, serial, half-duplex IR data link, and (2) IR remote control transmission operating at 940 nm for universal remote control applications. For infrared data communication, the HSDL-3002 provides the flexibility of Low Power SIR applications and remote control applications depending on the application circuit designs as outlined in the Application Circuit section. The transceiver is compliant to IrDA Physical Layer Specifications version 1.4 from 9.6 kbit/s to 115.2 kbit/s and it is IEC 825-Class 1 Eye Safe. The HSDL-3002 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. Features • Guaranteed temperature performance, –20 to 70°C – Critical parameters are guaranteed over temperature and supply voltage • Low power consumption • Small module size – Height: 2.70 mm – Width: 9.10 mm – Depth: 3.65 mm • Withstands >100 mV p-p power supply ripple typically • VCC supply 2.7 to 5.5 volts • Integrated EMI shield • Designed to accommodate light loss with cosmetic windows • IEC 825-class 1 eye safe IrDA Data Features • Fully compliant to IrDA physical layer specifications version 1.4 from 9.6 kbit/s to 115.2 kbit/s – Excellent nose-to-nose operation – Link distance up to 50 cm • Complete shutdown for TXD(IrDA), RXD(IrDA), and PIN diode • Low shutdown current (10 nA typical) • LED stuck-high protection Remote Control Features • High radiant intensity • Spectrally suited to remote control receiver • Typical link distance at 6 m Applications • Mobile data communication and universal remote control – PDAs – Mobile phone Application Support Information The Application Engineering Group is available to assist you with the application designs associated with the HSDL-3002 infrared transceiver module. You can contact them through your local sales representatives for additional details. Ordering Information Part Number Packaging Type Package Quantity HSDL-3002-007 Tape and Reel Front View 2500 Marketing Information The unit is marked with a number “1” and “YWWLL” on the shield for front option. Y = year WW = work week LL = lot information VCC CX2 CX1 GND (8) NC (7) RXD (IrDA) (4) SD (5) RECEIVER VCC (6) HSDL-3002 SHIELD V (RC) (2) IrDA TXD TXD (IrDA) (3) REMOTE CONTROL INPUT (RCI) TRANSMITTER REAR VIEW LEDA (1) R2 R1 8 7 6 5 4 3 2 1 VCC Figure 1. Functional block diagram of HSDL-3002. 2 Figure 2. Rear view diagram with pin-out. I/O Pins Configuration Table Pin Symbol I/O Description Notes 1 LED A I IR and Remote Control LED Anode Tied through external resistor, R1, to regulate VCC from 2.7 to 5.5 Volt 2 V(RC) I Remote Control LED Cathode Connected to an external switching transistor. Do not float the input pin of the swithcing transistor. 3 TXD (IrDA) I IrDA Transmitter Data Input. Active High Logic high turns on the LED. If held high longer than ~50 µs, the LED is turned off. TXD (IrDA) must be driven either high or low. DO NOT leave the pin floating. 4 RXD (IrDA) O IrDA Receiver Data Output. Active Low Output is at low pulse response when light pulse is seen. 5 SD I Shutdown. Active High Complete shutdown TXD(IrDA), RXD(IrDA), and PIN diode 6 VCC I Supply Voltage Regulated, 2.7 to 5.5 Volt 7 NC - No internal connection 8 GND I Connect to system ground Connect to system ground - SHIELD - EMI Shield 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 Recommended Value R1[1] 2.2 Ω ± 5%, 0.25 Watt for 2.7 ≤ VCC ≤ 3.3 V 2.7 Ω ± 5%, 0.25 Watt for 3.0 ≤ VCC ≤ 3.6 V 6.8 Ω ± 5%, 0.25 Watt for 4.5 ≤ VCC ≤ 5.5 V R2 0 Ω, 0.25 Watt for 4.5 ≤ VCC ≤ 5.5 V CX1[2] 0.47 µF ± 20%, X7R Ceramic CX2[3] 6.8 µF ± 20%, Tantalum Q1 N-Channel Logic Level MOSFET (Philip’s BSH103) with less than 1 Ω ‘ON’ resistance Notes: 1. R1 is used to optimize the performance of the 870 nm LED, while R2 is the current limiting resistor for the 940 nm RC LED. 2. CX1 must be placed within 0.7 cm of HSDL-3002 to obtain optimum noise immunity. 3. In environment with noisy power supplies, supply rejection can be enhanced by including CX2 as shown in Figure 1. 3 Transceiver I/O Truth Table Inputs Outputs Transceiver Mode Shutdown IrDA (TXD) Remote Control Input EI IR LED RC LED RXD Active 0 0 0 High[4] Off Off Low[5] Active 0 0 0 Low Off Off High Active 0 0 1 X Off On Not Valid Active 0 1 0 X On Off Not Valid Active 0 1 1 X On On Not Valid Shutdown 1 X[6] X[6] Low Not Valid Not Valid Not Valid X = Don’t Care EI = In-Band Infrared Intensity at detector Notes: 4. In-Band EI ≤ 115.2 kb/s. 5. Logic Low is a pulsed response. The condition is maintained for duration dependent on the pattern and strength of the incident intensity. 6. To maintain low shutdown current, TXD need to be driven high or low and not left floating. The Remote Control Input should be tied low. CAUTION: The BiCMOS inherent to this 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 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 –20 70 °C LED Supply Voltage VLED 0 7 V Supply Voltage VCC 0 7 V Output Voltage: RXD VO –0.5 7 V LED Current Pulse Amplitude ILED 500 mA Conditions ≤ 90 µs Pulse Width ≤ 20% duty cycle Recommended Operating Conditions Parameter Symbol Min. Max. Units Operating Temperature TA –20 70 °C Supply Voltage VCC 2.7 5.5 V Logic Input Voltage for TXD Logic High VIH 2/3 VCC VCC V Logic Low VIL 0 1/3 VCC V Logic High EIH 0.0081 500 mW/cm2 For in-band signals ≤ 115.2 kbps[7] Logic Low EIL 0.3 mW/cm2 For in-band signals[7] tTPW (SIR) 1.5 1.6 µs 115.2 kbps Receiver Input Irradiance TXD Pulse Width (SIR) Receiver Data Rate 4 9.6 Conditions tPW (TXD) = 1.6 µs at 115.2 kbps Electrical & 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 with VCC set to 3.0 V unless otherwise noted. Parameter Symbol Min. Typ. Max. Units Viewing Angle 2θ1/2 30 Peak Sensitivity Wavelength λp RXD Output Voltage Logic High VOH VCC -0.2 VCC V Logic Low Conditions Receiver ° 875 nm IOH=-200 µA, EI ≤ 0.3 µW/cm2 VOL 0 0.4 V RXD Pulse Width (SIR)[8] tRPW (SIR) 1 7.5 µs θ1/2 ≤ 15°, CL = 9 pF RXD Rise and Fall Times tr, tf 25 100 ns CL = 9 pF Receiver Latency Time[9] tL 25 50 µs EI = 4 µW/cm2 Receiver Wake Up Time[10] tRW 18 100 µs EI = 10 mW/cm2 IR Transmitter IR Radiant Intensity IEH 10 IR Viewing Angle 2θ1/2 30 IR Peak Wavelength λp TXD Logic Levels mW/sr ILEDA = 350 mA, θ1/2 ≤ 15°, TXD ≥ VIH. TA = 25°C, V(RCI) ≤ VIL 40 60 875 ° nm High VIH 2/3 VCC VCC V Low VIL 0 1/3 VCC V High IH 0.02 1 µA VI ≥ VIH Low IL -0.02 1 µA 0 ≤ VI ≤ VIL Shutdown IVLED 20 1000 nA VI(SD) ≥ VIH, TA = 25°C Wakeup Time[11] tTW 30 100 ns Maximum Optical PW[12] tPW(Max) 25 50 µs TXD Rise and Fall Time (Optical) tr, tf 600 ns LED Anode on State Voltage VON(LEDA) 2.2 V TXD Input Current LED Current –1 ILEDA = 350 mA, VI(TXD) ≥ VIH, V(RCI) ≤ VIL RC Transmitter mW/sr ILEDA = 400 mA, θ1/2 ≤ 15°, TXD ≤ VIL, TA = 25°C, V(RCI) ≥ VIH Remote Control (RC) Radiant Intensity[13] IEH 5 20 RC Viewing Angle 2θ1/2 30 RC Peak Wavelength λp 940 High IH 0.01 1 µA VI ≥ VIH Low IL –0.02 1 µA 0 ≤ VI ≤ VIL Shutdown ICC1 0.01 1 µA VSD ≥ VCC - 0.5; TA = 25°C Idle ICC2 290 450 µA VI(TXD) ≤ VIL, EI = 0 Active ICC3 2 8 mA VI(TXD) ≥ VIL 60 ° nm Transceiver Input Current Supply Current 5 –1 Notes: 7. 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. 8. For in band signals 2.4 kbps to 115.2 kbps where 3.6 µW/cm2 ≤ EI ≤ 500 mW/cm2. 9. Latency is defined as the time from the last TXD light output pulse until the receiver has recovered full sensitivity. 10. Receiver Wake up time is measured from VCC power on to valid RXD output. 11. Transmitter wake up time is measured from VCC power on to valid light output in response to a TXD pulse. 12. 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. 13. The VIH and VIL, when used in reference with RCI, depend on the switching transistor used and should obtain from the transistor datasheet. ILED vs. RADIANT INTENSITY (mW/Sr) FOR THE 870 nm LED TEMPERATURE = 25°C VLEDA vs. ILED FOR 870 nm LED TEMPERATURE = 25°C 2.5 70 2.3 50 VLEDA (VOLTS) RADIANT INTENSITY (mW/sr) 2.4 60 40 30 20 2.2 2.1 2.0 1.9 1.8 1.7 10 1.6 1.5 0 50 100 150 200 250 300 350 400 450 500 550 50 100 150 200 250 300 350 400 450 500 550 ILED (mA) ILED (mA) Figure 3. IR LOP vs. ILED. Figure 4. IR VLED vs. ILED. ILED vs. RADIANT INTENSITY (mW/Sr) OF THE 940 nm LED TEMPERATURE = 25°C VLEDA vs. ILED FOR THE 940 nm LED TEMPERATURE = 25°C 2.5 40 2.0 35 VLEDA (VOLTS) RADIANT INTENSITY (mW/sr) 45 30 25 20 15 5 0 50 150 250 350 450 ILED (mA) Figure 5. RC LOP vs. ILED. 6 1.0 0.5 10 0 50 1.5 550 650 150 250 350 450 ILED (mA) Figure 6. RC VLED vs. ILED. 550 650 tpw VOH 90% 50% VOL 10% tf tr Figure 7. RXD output waveform. tpw LED ON 90% 50% 10% LED OFF tr tf Figure 8. LED optical waveform. TXD LED tpw (MAX.) Figure 9. TXD “Stuck ON” protection. SD SD RX LIGHT TXD RXD TX LIGHT tRW Figure 10. Receiver wakeup time definition. 7 tTW Figure 11. Transmitter wakeup time definition. HSDL-3002 Package Outline (with Integrated Shield) 4.55 MOUNTING CENTER 0.885 9.10 ± 0.15 2.70 ± 0.15 1.35 2.65 2.60 ;; ; ;; ; ; ;; ;;;; ;;; ;;; ; 1.25 5.80 1.55 R 1.50 R 1.10 3.65 2.95 1 COPLANARITY: +0.05 TO -0.15 2 3 4 PITCH 1.00 5 6 7 8 0.65 0.80 0.50 ALL DIMENSIONS IN MILLIMETERS (mm). DIMENSION TOLERANCE IS 0.2 mm UNLESS OTHERWISE SPECIFIED. Figure 12. Package outline dimension. 8 HSDL-3002 Tape and Reel Dimensions 4.00 ± 0.10 5.00° (MAX.) 1.75 ± 0.10 1.13 ± 0.10 1.55 ± 0.05 POLARITY PIN 8: GND +0.10 3.46 0 7.50 ± 0.10 16.00 ± 0.30 9.50 ± 0.10 +0.10 3.30 0 PIN 1: VLED 8.00 ± 0.10 0.40 ± 0.10 3.00 ± 0.10 8.00° (MAX.) MATERIAL OF CARRIER TAPE: CONDUCTIVE POLYSTYRENE MATERIAL OF COVER TAPE: PVC 3.40 ± 0.20 METHOD OF COVER: HEAT ACTIVATED ADHESIVE 4.20 ± 0.20 PROGRESSIVE DIRECTION EMPTY (40 mm MIN.) LEADER PARTS MOUNTED (400 mm MIN.) EMPTY (40 mm MIN.) "B" "C" 330 QUANTITY 80 2500 UNIT: mm DETAIL A DIA. 13.00 ± 0.50 R 1.00 B C 2.00 ± 0.50 LABEL 16.40 + 2.00 0 21.00 ± 0.80 DETAIL A Figure 13. Tape and reel dimensions. 9 2.00 ± 0.50 Moisture Proof Packaging Baking Conditions All HSDL-3002 options are shipped in moisture proof package. Once opened, moisture absorption begins. If the parts are not stored in dry conditions, they must be baked before reflow to prevent damage to the parts. This part is compliant to JEDEC Level 4. Package Temp. In reels 60°C ≥ 48 hours In bulk 100°C ≥ 4 hours 125°C ≥ 2 hours 150°C ≥ 1 hour UNITS IN A SEALED MOISTURE-PROOF PACKAGE Baking should only be done once. Recommended Storage Conditions PACKAGE IS OPENED (UNSEALED) ENVIRONMENT LESS THAN 25°C, AND LESS THAN 60% RH? YES PERFORM RECOMMENDED BAKING CONDITIONS Figure 14. Baking conditions chart. 10 Storage Temperature 10°C to 30°C Relative Humidity below 60% RH YES NO BAKING IS NECESSARY NO PACKAGE IS OPENED MORE THAN 72 HOURS Time NO Time from Unsealing to Soldering After removal from the bag, the parts should be soldered within three days if stored at the recommended storage conditions. Reflow Profile MAX. 245°C T – TEMPERATURE – (°C) 230 R4 R3 200 183 170 150 R2 90 sec. MAX. ABOVE 183°C 125 R1 100 R5 50 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 15. Reflow graph. Process Zone Symbol ∆T Maximum DT/Dtime Heat Up P1, R1 25°C to 125°C 4°C/s Solder Paste Dry P2, R2 125°C to 170°C 0.5°C/s Solder Reflow P3, R3 170°C to 230°C (245°C at 10 seconds max.) 4°C/s P3, R4 230°C to 170°C –4°C/s P4, R5 170°C to 25°C –3°C/s Cool Down The reflow profile is a straightline 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-3602 castellation I/O pins are heated to a temperature of 125°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-3602 castellation I/O pins. 11 Process zone P2 should be of sufficient time duration (>60 seconds) to dry the solder paste. The temperature is raised to a level just below the liquidus point of the solder, usually 170°C (338°F). Process zone P3 is the solder reflow zone. In zone P3, the temperature is quickly raised above the liquidus point of solder to 230°C (446°F) for optimum results. The dwell time above the liquidus point of solder should be between 15 and 90 seconds. It usually takes about 15 seconds to assure proper coalescing of the solder balls into liquid solder and the formation of good solder connections. Beyond a dwell time of 90 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 170°C (338°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 -3°C per second maximum. This limitation is necessary to allow the PC board and HSDL-3602 castellation I/O pins to change dimensions evenly, putting minimal stresses on the HSDL3602 transceiver. Appendix A : SMT Assembly Application Note 1.0 Solder Pad, Mask and Metal Stencil METAL STENCIL FOR SOLDER PASTE PRINTING STENCIL APERTURE LAND PATTERN SOLDER MASK PCBA Figure 16. Stencil and PCBA. 1.1 Recommended Land Pattern 2.65 3.05 MOUNTING CENTER 1.175 1.10 0.50 0.715 2.30 1.20 8 7 0.725 Figure 17. Land pattern. 12 6 5 4 1.00 3 2 1 0.65 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 3.05 mm x 1.1 mm as per land pattern. 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. APERTURES AS PER LAND DIMENSIONS t w l Figure 18. Solder stencil aperture. Aperture size(mm) Stencil thickness, t (mm) length, l width, w 0.152 mm 2.60 ± 0.05 0.55 ± 0.05 0.127 mm 3.00 ± 0.05 0.55 ± 0.05 10.1 0.2 3.85 3.2 SOLDER MASK UNITS: mm It is recommended that two fiducial crosses be placed at midlength of the pads for unit alignment. Note: Wet/Liquid PhotoImageable solder resist/mask is recommended. 13 Figure 19. Adjacent land keepout and solder mask areas. Appendix B : PCB Layout Suggestion The following shows an example of a PCB layout 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. 2. The shield trace is a wide, low inductance trace back to the system ground. 3. The AGND pin should be connected to the ground plane and not to the shield tab. 4. C1 and C2 are optional supply filter capacitors; they may be left out if a clean power supply is used. 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 current limiting resistor R2. In a noisy environment, supply rejection can be enhanced by including C2 as well. The layout corresponds to the following application circuit diagram. Top View Bottom View VCC CX2 GND CX1 RECEIVER NC RxD DIP SWITCH SD R1 RC Q1 TRANSMITTER TxD VCC R2 Figure 20. PCB layout suggestion. 14 R2 is the current limiting resistor, while R1 is a weak pull down resistor for the input of the switching transistor. Do not float the input of the switching MOSFET. The DIP switch is used to select between driving the 875 nm or 940 nm LED. Appendix C : General Application Guide for the HSDL-3002 Infrared IrDA® Compliant 115.2 Kb/s Transceiver computing market such as PDAs, as well as small embedded mobile products such as digital cameras and cellular phones. It also includes a 940 nm LED to support universal remote control applications. It is fully compliant to IrDA 1.4 low power specification from 9.6 kb/s to 115.2 kb/s, and supports most remote control codes. The design of the HSDL- Description The HSDL-3002, a wide voltage operating range infrared transceiver is a low-cost and small form factor device that is designed to address the mobile 3002 also includes the following unique features: • An additional spectrally suited 940 nm LED • 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 Conditions 2.2 Ω 3.0 V 40 mW/sr 350 mA Turn on 870 nm LED only TxD ≥ VIH, V(RC) ≤ VIL 20 mW/sr 400 mA Turn on 940 nm LED only TXD ≤ VIL, V(RC) ≥ VIH The resistor value chosen above is for optimal IrDA operation. For optimized remote control performance, it is recommended to turn on both the 870 nm and 940 nm LEDs. Moreover, separate power control feature can be incorporated for remote control operation by implementing device as shown in Figure 3. Interface to Recommended I/O Chips The HSDL-3002’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 V(RC), pin 2, in conjunction with TxD (IrDA), pin 3, can be used to send remote control codes. Pin 2 is driven through a switching FET transistor with a very low onresistance capable of driving 400 mA of current for remote control operation. The block diagram below shows how the IrDA port fits into a mobile phone and PDA platform. SPEAKER AUDIO INTERFACE DSP CORE MICROPHONE ASIC CONTROLLER RF INTERFACE TRANSCEIVER MOD/ DE-MODULATOR IR RC MICROCONTROLLER USER INTERFACE HSDL-3002 MOBILE PHONE PLATFORM Figure 21. IR layout in mobile phone platform. 15 LCD PANEL RC RAM IR HSDL-3002 CPU FOR EMBEDDED APPLICATION ROM PCMCIA CONTROLLER TOUCH PANEL RS232C DRIVER COM PORT PDA PLATFORM Figure 22. IR layout in PDA platform. The link distance testing was done using typical HSDL-3002 units with National Semiconductor’s PC87109 3 V Super I/O controller and SMC’s FDC37C669 and FDC37N769 Super I/O controllers. An IrDA link distance of up to 100 cm was demonstrated. 16 Remote Control Operation HSDL-3002 comes with an additional spectrally suited 940 nm LED for remote control applications. Remote control applications are not governed by any standards, owing to which there are numerous remote control codes in the market. Each of these standards results in receiver modules with different sensitivities, depending on the carrier frequencies and responsivity to the incident light wavelength. Based on a survey of some commonly used remote control receiver modules, the irradiance is found to be in the range of 0.05~0.07 µW/cm2. Based on a typical irradiance of 0.075 µW/ cm2 and turning on both 870 nm and 940 nm LEDs, a typical link distance of 6 m is achieved. For a more exhaustive note on implementing remote control using HSDL-3002, please refer to the application note. Appendix D : Window Designs for HSDL-3002 Optical port dimensions for HSDL-3002 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-3002 to the back of the window. The distance from the center of the LED lens to the center of the photodiode lens, K, is 5.8 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-3002, D, is 8.6 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: ;;;;;;;; ;;;;;; ;;;;;;;;; ;;;;;; ;;;;;;;; ;;; ;;;;; ;; OPAQUE MATERIAL IR TRANSPARENT WINDOW Y X IR TRANSPARENT WINDOW OPAQUE MATERIAL K Z A D Figure 23. Window design diagram. 17 Aperture Height (y, mm) Module Depth (z) mm Max. Min. Max. Min. 0 15.73 10.41 9.93 4.61 1 16.89 10.94 11.09 5.14 2 18.04 11.48 12.24 5.68 3 19.19 12.02 13.39 6.22 4 20.35 12.55 14.55 6.75 5 21.5 13.09 15.7 7.29 6 22.66 13.62 16.86 7.82 7 23.81 14.16 18.01 8.36 8 24.97 14.7 19.17 8.90 9 26.12 15.23 20.32 9.43 APERTURE WIDTH (X) vs. MODULE DEPTH APERTURE HEIGHT (Y) vs. MODULE DEPTH 30 25 APERTURE HEIGHT (Y) – mm APERTURE WIDTH (X) – mm Aperture Width (x, mm) 25 20 15 10 X MAX. X MIN. 5 0 0 1 2 3 4 5 6 7 8 9 20 15 10 5 0 Y MAX. Y MIN. 0 1 MODULE DEPTH (Z) – mm 2 3 4 5 6 7 8 9 MODULE DEPTH (Z) – mm Figure 24. Aperture width (X) vs. module depth. Figure 25. Aperture height (Y) vs. module depth. Window Material 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. Almost any plastic material will work as a window material. Polycarbonate is recommended. The surface finish of the plastic should be smooth, without any Recommended Plastic Materials Material # Light Transmission Haze Refractive Index Lexan 141L 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 141L. Recommended Dye: Violet #21051 (IR transmissant above 625 nm) The recommended plastic materials for use as a cosmetic window are available from General Electric Plastics. 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 Flat Window (First choice) Figure 26. Shape of windows. 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. Curved Front and Back (Second choice) Curved Front, Flat Back (Do not use) For company and product information, please go to our web site: WWW.liteon.com or http://optodatabook.liteon.com/databook/databook.aspx Data subject to change. Copyright © 2007 Lite-On Technology Corporation. All rights reserved.