LTE-R38381L-S Infrared Emitter and Detector Datasheet - 940nm Wavelength - 1A Forward Current - 1.8W Power - Technical Documentation

1. Product Overview

Takardar nan tana ba da cikakkiyar ƙayyadaddun fasaha na ɓangaren fitar da hasken infrared mai rabuwa. Na'urar an tsara ta musamman don aikace-aikacen da ke buƙatar tushen hasken infrared mai ƙarfi, amintacce. Tana amfani da guntu na gallium arsenide (GaAs), tana haskakawa a tsayin raƙuman raƙuman 940 nanometers, wanda ke cikin kewayon hasken infrared na kusa, wanda idon ɗan adam ba zai iya gani ba. Babban aikin ɓangaren shine zama tushen fitar da hasken infrared da aka sarrafa a cikin tsarin lantarki daban-daban.

1.1 Core Advantages and Target Market

Bangaren yana ba da fa'idodi masu mahimmanci da yawa don aikace-aikacen infrared. Yana da ƙarfin haske mai ƙarfi, yana ba da damar watsa sigina mai ƙarfi. Ɗabarun sa yana goyan bayan babban ƙarfin tuƙi, wanda ke taimakawa haɓaka ƙarfin fitarwa. Na'urar kuma tana da tsawon rayuwa mai tsawo da ingantaccen aminci. Ta dace da ƙa'idodin muhalli kamar RoHS, kuma samfur ne mai kore. Manufar aikace-aikacen wannan mai fitar da infrared sun faɗaɗa, suna mai da hankali musamman akan masu fitar da infrared don tsarin sarrafa nesa, da kuma firikwensin infrared da aka ɗora akan PCB don ganowa kusa, hango abu, ko canja wurin bayanai.

2. Technical Parameters: In-depth and Objective Interpretation

Sashe mai zuwa yana ba da cikakken, mai ƙima bincike na mahimman ƙayyadaddun fasaha na na'urar bisa ga iyakokin ƙayyadaddun ta.

2.1 Absolute Maximum Ratings

These ratings define the stress limits that may cause permanent damage to the device. Operation at or beyond these limits is not guaranteed and should be avoided in reliable designs.

• Power Dissipation (Pd):1.8 Watts. This is the maximum power the device can dissipate as heat when the ambient temperature (TA) is 25°C. Exceeding this value will cause excessive junction temperature rise.
• Peak Forward Current (IFP):5 Amperes. This is the maximum current allowed under pulse conditions (300 pulses per second, 10 microsecond pulse width). It is significantly higher than the DC rating, utilizing the thermal inertia of the device.
• DC Forward Current (IF):1 Ampere. This is the maximum continuous forward current the device can withstand.
• Reverse Voltage (VR):5 volts. Applying a reverse voltage higher than this value may cause semiconductor junction breakdown.
• Thermal Resistance (RθJ):10 K/W. This parameter indicates the efficiency of heat conduction from the semiconductor junction to the environment. A lower value means better heat dissipation performance.
• Operating Temperature Range:-40°C to +85°C. Ensures the device operates normally within this ambient temperature range.
• Storage Temperature Range:-55°C to +100°C.

2.2 Electrical and Optical Characteristics

These are typical and guaranteed performance parameters measured under specified test conditions (unless noted, TA=25°C).

• Radiant Intensity (I_E):160 mW/sr (min). This parameter measures the optical power emitted per unit solid angle (steradian) along the axis. It defines the intensity of the beam in a specific direction.
• Total Radiant Flux (Φ_e):590 mW (typ). This is the total optical power emitted by the device in all directions (4π steradians).
• Peak Emission Wavelength (λ_P):940 nm (typ). The wavelength at which the emitted optical power reaches its maximum.
• Spectral Line Half-Width (Δλ):50 nm (typical value). This is the spectral bandwidth when the radiation intensity is at least half of its peak value. It describes the purity of the emitted light color (wavelength).
• Forward voltage (V_F):1.8V (typical), 2.3V (maximum), at I_F=1A condition. The voltage drop across the device when conducting the specified forward current.
• Reverse current (I_R):10 μA (maximum), at V_R=5V condition. The small leakage current flowing through the device when it is reverse biased.
• Rise/fall time (t_r/t_f):30 ns (typical). The time required for the optical output to respond to a step current, rising from 10% to 90% (or falling from 90% to 10%) of its final value. This determines the maximum modulation speed.
• Viewing angle (2θ_1/2):90 degrees (typical). The full angle at which the radiant intensity is half of the center (0°) value. A 90° angle indicates a wide beam pattern.

3. Performance Curve Analysis

The datasheet contains multiple graphs illustrating the device's behavior under various conditions. These curves are crucial for understanding nonlinearity and temperature dependence.

3.1 Spectral Distribution

The graph (Figure 1) shows the relationship between relative radiant intensity and wavelength. The curve is centered at 940 nm with a typical half-width of 50 nm. This confirms that the device emits light in the near-infrared region, which is optimal for many sensors and remote controls that filter out visible light.

3.2 Forward Current vs. Forward Voltage (I-V Curve)

The I-V curve (Figure 3) shows the typical exponential relationship of a diode. At the rated current of 1A, the typical forward voltage is 1.8V. Designers must ensure the drive circuit can provide this voltage at the required current.

3.3 Temperature Dependence

Key graphs illustrate the effect of temperature:

• Forward Current vs. Ambient Temperature (Figure 2):It shows how the maximum allowable forward current decreases with increasing ambient temperature due to a fixed power dissipation limit.
• Relative Radiant Intensity vs. Ambient Temperature (Figure 4):It indicates that the optical output power decreases with increasing junction temperature. This is a key factor for maintaining performance consistency.
• Relative radiant intensity vs. forward current (Figure 5):It shows a sublinear relationship between drive current and light output, especially at higher currents, where efficiency may decrease and heat generation increases.

3.4 Radiation Pattern

The radiation pattern (Figure 6) is a polar plot showing the angular distribution of emitted light. The 90° viewing angle is visually confirmed, showing intensity drops to half at ±45° from the central axis. This pattern is important for aligning the emitter with the detector or ensuring sufficient coverage in sensing applications.

4. Mechanical and Packaging Information

4.1 Outline Dimensions

The device uses a standard through-hole package form. The outline drawing specifies body dimensions, lead spacing, and lead diameter. Unless otherwise specified, all dimensions are in millimeters, with a typical tolerance of ±0.1 mm. The cathode is marked on the package, which is crucial for correct orientation during PCB assembly.

4.2 Recommended Pad Dimensions

The diagram provides recommended land pattern (footprint) dimensions for PCB design. Adhering to these recommendations helps ensure reliable solder joints and proper mechanical stability after wave soldering or reflow soldering.

5. Soldering and Assembly Guide

5.1 Soldering Conditions

The datasheet provides clear guidance for two soldering methods:

• Reflow soldering:Recommended for surface mount assembly. The temperature profile must include a preheat phase (150-200°C), a peak temperature not exceeding 260°C, and the time above 260°C should be no longer than 10 seconds. The device can withstand this temperature profile a maximum of two times.
• Hand soldering (soldering iron):The soldering iron tip temperature should not exceed 300°C, and the contact time per lead should be limited to within 3 seconds. This operation should be performed only once.

Provides a JEDEC-compliant reflow temperature profile as a general target reference, emphasizing the need to adhere to both JEDEC limits and the solder paste manufacturer's specifications.

5.2 Storage and Handling

• Storage (sealed bag):Devices should be stored in an environment of ≤30°C and relative humidity (RH) ≤90%. In a moisture barrier bag with desiccant, the shelf life is one year.
• Storage (Opened Bag):After opening, the ambient conditions should not exceed 30°C / 60% RH. Components should be used within one week. For long-term storage outside the original packaging bag, they must be stored in a sealed container with desiccant or in a nitrogen dry box.
• Baking:If devices are exposed to ambient air for more than one week, baking before soldering is recommended, at 60°C for at least 20 hours, to remove absorbed moisture and prevent "popcorn" effect during reflow.

5.3 Cleaning

If cleaning is required after soldering, only alcohol-based solvents such as isopropyl alcohol should be used to avoid damage to the package or lens material.

5.4 Tso tawm txoj kev

A key design note emphasizes that LEDs are current-driven devices. To ensure uniform brightness when driving multiple LEDs in parallel, an independent current-limiting resistor must be connected in series with each LED. This compensates for the slight differences in the forward voltage (V_F) of individual devices, preventing uneven current and inconsistent illumination or output power.

6. Kev kho qhov chaw thiab kev nias khoom

6.1 Cov ntaub ntawv kho qhov chaw thiab cov khoom nias

Detailed mechanical drawings specify the dimensions of the carrier tape, the cavities that hold the components, and the overall reel (mentioning a diameter of 7 inches). The carrier tape is sealed with a cover tape to protect the components during transportation and automated assembly.

6.2 Cov ntaub ntawv kho qhov chaw

Key packaging details include:

• Reel size: 7 inches.
• Yawa: 600 a kowane nadi.
• Inganci: Matsakaicin adadin abubuwan da suka ɓace a cikin tef ɗin jigilar kaya shine biyu.
• Ma'auni: Marufi ya dace da ƙa'idar ANSI/EIA 481-1-A-1994.

7. Application Recommendations and Design Considerations

7.1 Typical Application Scenarios

Dangane da ƙayyadaddun sa, wannan mai fitar da infrared ya dace sosai don amfani a:

• Infrared Remote Control:For televisions, audio systems, and other consumer electronics. The 940nm wavelength is standard for most infrared receivers.
• Proximity and Object Sensing:Paired with a photodiode or phototransistor to detect the presence, absence, or distance of an object by reflecting its infrared light.
• Optical Switches and Encoders:Interrupting the light beam between an emitter and a detector to create a contactless switch or to measure rotation/position.
• Short-Range Data Transmission:Used for applications like IrDA or simple wireless data links, utilizing its fast rise/fall times for modulation.

7.2 Design Considerations

• Thermal Management:With a power dissipation of 1.8W and a thermal resistance of 10 K/W, driving the device at maximum DC current generates significant heat. For continuous operation, especially at high ambient temperatures, sufficient PCB copper area (thermal pad) or a heatsink may be required.
• Current Drive Circuit:Use a constant current driver or a voltage source with a series resistor to set the current. Avoid driving directly from a logic pin or an unregulated voltage source.
• Optical Design:Consider the 90° viewing angle. For long-distance or directional beams, a lens may be needed to collimate the light. For wide-area illumination, the native angle may be sufficient.
• Pairing with Detector:Ensure the selected photodetector (PIN photodiode, phototransistor) is sensitive to the 940nm region. Using a detector with a daylight blocking filter will improve the signal-to-noise ratio under ambient light conditions.

8. Technical Comparison and Differentiation

While a direct comparison requires specific competitor data, according to its own datasheet, the key differentiating features of this device include:

• High Power Capability:A 1A DC forward current and 5A pulsed current rating indicate its robust chip and package design, enabling high output.
• Wide Viewing Angle:A 90° angle provides broad coverage, suitable for sensing applications with less stringent alignment requirements or requiring area illumination.
• Fast Switching Speed:Typical 30ns rise/fall times enable high-frequency modulation, allowing for faster data transmission rates in communication applications compared to slower devices.
• Proven Reliability:Referencing JEDEC standards and detailed soldering/moisture sensitivity guidelines indicates the component is designed for robust manufacturing processes.

9. Frequently Asked Questions (Based on Technical Parameters)

9.1 Can I drive this LED directly with a 5V microcontroller pin?

No, this is not recommended and could damage the LED or the microcontroller.This LED has a typical forward voltage drop of 1.8V at 1A. A microcontroller pin cannot supply 1A, and connecting it directly to 5V without current limiting would attempt to draw a destructively high current. You must use a driver circuit (transistor/MOSFET) with a series resistor to limit the current to the desired value.

9.2 Why does the output decrease at high temperatures?

Ingantaccen kayan semiconductor don canza wutar lantarki zuwa haske (ingancin quantum na ciki) yana raguwa yayin da zafin jiki ya tashi. Wannan wani siffa ce ta asali ta zahiri. Hoton da ke cikin Figure 4 yana ƙididdige wannan raguwa, wanda dole ne a yi la'akari da shi a cikin ƙirar da ke aiki a cikin kewayon zafin jiki mai faɗi, don tabbatar da daidaiton aikin gani.

9.3 What is the difference between radiant intensity and total radiant flux?

Ƙarfin radiation (mW/sr)shineJagorancima'auni: ikon da aka fitar zuwa takamaiman kusurwar sararin samaniya (yawanci tare da tsakiya). Wannan yana da mahimmanci ga aikace-aikacen da aka sanya na'urar ganowa a wani takamaiman wuri.Total Radiant Flux (mW)是总The integrated power emitted in all directions (over the entire sphere). It represents the total "brightness" of the emitter regardless of direction. A device may have a high total flux but low axial intensity if the light is spread very wide.

9.4 Yaya muhimmanci ne lokacin amfani na mako ɗaya bayan buɗe jakar?

This is very important for reliable soldering. Plastic packages absorb moisture from the air. During the high-temperature reflow process, this trapped moisture rapidly vaporizes, causing internal delamination, cracking, or "popcorning," which damages the component. The 1-week limit and baking requirements are based on the package's Moisture Sensitivity Level (MSL) to prevent these failures.

10. Ayyukan ƙira da amfani na ainihi

Case: Designing a Multi-Emitter Object Detection Barrier
A system requires an infrared light curtain to detect objects passing through a 50 cm wide channel. Five pairs of emitter-detectors will be used.

1. Circuitu mai gudanarwa:Kowane mai fitarwa zai kasance yana gudanar da MOSFET na N-channel na musamman, wanda aka sarrafa ta hanyar siginar PWM na microcontroller da aka raba don daidaita hasken infrared (misali, a 38kHz). Za a lissafta resistor mai iyakancewar kwarara ga kowane reshen LED: R = (V_{Wutar lantarki}- V_{F_LED}) / I_F. Ana ɗauka wutar lantarki ta 5V, V_F=1.8V, kuma I_F=500mA (don rage darajar aminci), R = (5 - 1.8) / 0.5 = 6.4Ω (amfani da daidaitaccen darajar 6.2Ω). Ƙarfin da resistor ya kware dole ne ya kasance aƙalla I²R = (0.5)²*6.2 ≈ 1.55W, so a 2W or 3W resistor is required.
2. Thermal Management:The power consumption of each LED P = V_F* I_F= 1.8V * 0.5A = 0.9W. The PCB should have large copper pour areas connected to the LED cathode and anode pads to act as a heat sink, keeping the junction temperature within a safe range.
3. Optical Alignment:The 90° viewing angle simplifies alignment with the corresponding detector across the gap. Small tubular light shields can be placed around the emitter and detector to limit ambient light interference without overly restricting the beam.
4. Modulation:Drive the emitter with a 38kHz square wave, allowing the detector to be tuned to the same frequency, effectively filtering out constant ambient infrared light (such as from sunlight or lamps), thereby greatly improving detection reliability.

11. Taƙaitaccen bayani na aikin

This device is a light-emitting diode (LED) that operates in the infrared spectrum. Its core is a semiconductor chip made of gallium arsenide (GaAs). When a forward voltage is applied across the chip's P-N junction, electrons from the N-type material recombine with holes from the P-type material. This recombination process releases energy. In standard silicon diodes, this energy is primarily released as heat. However, in materials like GaAs, a significant portion of this energy is released as photons (light particles). The specific bandgap of the GaAs material determines the wavelength of these photons, which in this case is centered around 940 nm, placing it in the near-infrared region. The intensity of the emitted light is proportional to the recombination rate, which is controlled by the forward current flowing through the diode.

12. Trends na fasaha (hangen nesa na haƙiƙa)

The field of infrared emitters is evolving alongside broader optoelectronics trends. There is a constant drive towards higher power density and efficiency, allowing for brighter output with smaller packages or lower power consumption. This enables more compact sensor designs and longer battery life in portable devices. Integration is another key trend, where components combine the emitter, driver circuitry, and sometimes a basic detector or monitor photodiode into a single module or IC package, simplifying system design. Furthermore, advancements in materials, such as developing more efficient epitaxial structures or using new semiconductor compounds, aim to improve performance parameters like electro-optical conversion efficiency (light output per unit of electrical input) and temperature stability. Demand for devices supporting higher modulation speeds also persists, driven by applications in faster data communication and LiDAR (Light Detection and Ranging) systems. These trends focus on enhancing performance, reliability, and ease of use for system designers.