Reverse Mount SMD LED Datasheet - Orange - 5mA Forward Current - 2.3V Forward Voltage - Technical Documentation

1. Product Overview

This document details the specifications of a high-brightness, reverse-mount surface-mount device (SMD) light-emitting diode (LED). The device utilizes an aluminum indium gallium phosphide (AlInGaP) semiconductor chip, renowned for its high luminous efficiency and excellent color purity, particularly within the orange to red spectral range. Its primary application is as a compact, reliable indicator light in various electronic assemblies, suitable for space-constrained situations where a reverse-mount configuration is advantageous for design or aesthetics.

The core advantages of this component include compliance with the RoHS (Restriction of Hazardous Substances) directive, making it an environmentally friendly choice. It is packaged using industry-standard 8mm carrier tape wound on 7-inch reels, ensuring compatibility with high-speed automated pick-and-place assembly equipment. Furthermore, the device is designed to withstand the standard infrared (IR) reflow soldering processes commonly used in modern electronics manufacturing, facilitating easy integration into printed circuit board (PCB) assemblies.

2. In-depth Technical Parameter Analysis

.1 Absolute Maximum Ratings

Absolute maximum ratings define stress limits that may cause permanent damage to the device. These values must not be exceeded under any operating conditions.

• Power dissipation (Pd):75 mW. This is the maximum power that the LED package can dissipate in the form of heat without degrading performance or reliability.
• Peak Forward Current (I_F(peak)):80 mA. This is the maximum permissible instantaneous forward current, typically specified under pulse conditions (1/10 duty cycle, 0.1 ms pulse width) to prevent overheating of the semiconductor junction.
• Continuous Forward Current (I_F):30 mA DC. This is the maximum steady-state current that can be applied continuously.
• Reverse Voltage (V_R):5 V. Applying reverse voltage exceeding this value may cause LED breakdown and failure.
• Operating and Storage Temperature:-30°C to +85°C (operating), -40°C to +85°C (storage). These ranges ensure the mechanical and electrical integrity of the LED.
• Soldering Temperature:Can withstand 260°C for 10 seconds, meeting the requirements of the lead-free (Pb-free) soldering profile.

2.2 Electrical and Optical Characteristics

Unless otherwise specified, these parameters are measured at ambient temperature (T_a) measured under standard test conditions of 25°C and forward current (I_F) of 5 mA.

• Luminous intensity (I_V):ranges from a minimum of 11.2 millicandelas (mcd) to a maximum of 71.0 mcd. The actual measured value of a specific unit depends on its assigned bin code (see Section 3).
• Viewing angle (2θ_1/2):130 digiri. Wannan shine kusurwar cikakke inda ƙarfin haske ya ragu zuwa rabin ƙimar da aka auna a tsakiyar axis (0°). Irin wannan faɗin kusurwar gani ya zama ruwan dare ga LED masu amfani da ruwan tabarau mai tsabta, suna samar da nau'in haske mai faɗi da watsawa wanda ya dace da aikace-aikacen nuna alama.
• Peak wavelength (λ_P):Matsakaicin ƙimar 611 nanometers (nm). Wannan shine tsayin raƙuman ruwa inda fitar da ƙarfin bakan ya fi girma.
• Dominant Wavelength (λ_d):Typical value 605 nm. This is the single wavelength perceived by the human eye that defines the color of light, derived from the CIE chromaticity diagram. It is a key parameter for color specification.
• Spectral Bandwidth (Δλ):Typical value 17 nm. This is the Full Width at Half Maximum (FWHM) of the emission spectrum, indicating color purity. A smaller bandwidth indicates better monochromaticity of the light source.
• Forward Voltage (V_F):At 5 mA, ranging from 1.9V (min) to 2.3V (max). This is the voltage drop across the LED when forward current flows. Designers must ensure the drive circuit can provide sufficient voltage.
• Reverse Current (I_R):Maximum 10 µA at 5V reverse voltage. This is the small leakage current that flows when the LED is reverse-biased within its safe limits.
• Capacitance (C):Measured at 0V bias and 1 MHz, the typical value is 40 pF. This parasitic capacitance may need to be considered in high-frequency switching applications.

3. Bin System Description

To manage natural variations in the semiconductor manufacturing process, LEDs are sorted into different performance bins. This ensures consistency within a production batch. For this product, binning is primarily based on luminous intensity.

The bin code list defines four distinct groups:

• L bin:The luminous intensity ranges from 11.2 mcd to 18.0 mcd.
• M grade:The luminous intensity ranges from 18.0 mcd to 28.0 mcd.
• N grade:Luminous intensity from 28.0 mcd to 45.0 mcd.
• P gear:Luminous intensity from 45.0 mcd to 71.0 mcd.

The intensity value within each bin allows for a +/-15% tolerance. Designers should select the appropriate bin based on the brightness required by their application, understanding that under the same driving conditions, units from a higher bin (e.g., P bin) will be brighter than those from a lower bin (e.g., L bin).

4. Performance Curve Analysis

Although the datasheet references specific graphical curves (e.g., Figure 1 for spectral distribution, Figure 5 for viewing angle), the textual data allows for the analysis of key relationships.

Forward Current vs. Luminous Intensity:Luminous intensity is specified at I_F= 5mA. Typically, for AlInGaP LEDs, luminous intensity increases superlinearly with current at lower levels, then tends to saturate at higher currents due to thermal effects and efficiency droop. Operation significantly above the test current may yield higher output, but must be carefully managed within the absolute maximum ratings for current and power dissipation.

Forward Current vs. Forward Voltage:V_FGiven at a range of 5mA. The forward voltage has a negative temperature coefficient, meaning it decreases as the junction temperature increases. It also increases logarithmically with current.

Temperature Dependence:The light output of an LED decreases as its junction temperature rises. This characteristic is crucial for applications where the LED may operate in high-temperature environments or where significant self-heating occurs due to high drive currents. The specified operating temperature range of -30°C to +85°C defines the environment in which the LED operates within its published specifications.

5. Mechanical and Packaging Information

This device conforms to the EIA (Electronic Industries Alliance) standard package outline. As a reverse-mount type, the LED is designed to be mounted on the side of the PCB opposite the viewing surface, with light emitted through a hole or aperture in the board. This creates a smooth, flush appearance on the user side.

Detailed package dimensions, including body length, width, height, and pin locations, are provided in the datasheet drawings. These critical dimensions are necessary for designing the PCB pad layout, including the lens aperture and pad pattern.

Polarity Identification:The cathode is typically marked, for example, by a notch, a green dot, or a different pin length/shape. Correct polarity must be observed during assembly, as applying a reverse voltage exceeding 5V will damage the device.

Recommended pad dimensions:The datasheet contains recommended PCB land pattern (pad geometry). Following these recommendations helps to form reliable solder joints during reflow, ensure proper alignment and achieve good mechanical strength.

6. Soldering and Assembly Guide

6.1 Reflow Soldering Temperature Profile

Provides a recommended infrared (IR) reflow profile for Pb-free soldering processes. Key parameters of this profile include:

• Preheating zone:Heat up to 150-200°C.
• Soak/Preheat Time:Maximum 120 seconds to allow the PCB temperature to stabilize uniformly.
• Peak Temperature:Maximum 260°C. LED rated to withstand this temperature for up to 10 seconds.
• Time Above Liquidus (TAL):It is necessary to control the time the solder remains in a molten state to ensure proper solder joint formation while avoiding excessive thermal stress on the LED.

This profile is based on JEDEC standards, ensuring compatibility with standard Surface Mount Technology (SMT) assembly lines. Considering PCB thickness, component density, and solder paste type, characterizing a specific temperature profile for a particular PCB design is crucial.

6.2 Manual Soldering

If manual soldering is necessary, extreme caution must be exercised.

• The soldering iron temperature must not exceed 300°C.
• The soldering time for each pin must be limited to a maximum of 3 seconds.
• Soldering should be performed only once to avoid thermal damage to the plastic package and internal wire bonds.

6.3 Cleaning

Only the specified cleaning agents should be used. Recommended solvents include ethanol or isopropyl alcohol (IPA). LEDs should be immersed at room temperature for less than one minute. The use of harsh or unspecified chemicals may damage the epoxy lens and packaging material, leading to discoloration, cracking, or delamination.

6.4 Storage and Operation

• ESD (Electrostatic Discharge) Precautions:LEDs are sensitive to static electricity. Appropriate ESD control measures must be taken, including the use of grounded wrist straps, anti-static mats, and conductive containers.
• Moisture Sensitivity:This package has a Moisture Sensitivity Level (MSL). For devices removed from the original moisture barrier packaging (with desiccant), it is recommended to complete infrared reflow soldering within 672 hours (28 days) under storage conditions not exceeding 30°C and 60% relative humidity. If this window is exceeded, baking at approximately 60°C for at least 20 hours is required before soldering to remove absorbed moisture and prevent "popcorn" effect (package cracking) during reflow.

7. Packaging and Ordering Information

This product is supplied in carrier tape reel form compatible with automated assembly equipment.

• Carrier Tape Width:8 millimeters.
• Reel diameter:7 inches.
• Quantity per roll:3000 pieces.
• Minimum Order Quantity (MOQ):Minimum order quantity starts from 500 pieces.
• Packaging Standard:Compliant with ANSI/EIA-481 specification. Carrier tape pockets are sealed with cover tape. Maximum of two consecutive empty pockets (missing components) allowed.

Part NumberLTST-C230KFKT-5AUnique identifier for this specific model: reverse mount, water clear lens, AlInGaP chip, orange.

8. Application Notes and Design Considerations

Typical Application:This LED is suitable for general indicator purposes in consumer electronics, office equipment, communication devices, and home appliances. Its reverse-mount design is ideal for front panels, control interfaces, and status displays where a clean, aperture-based appearance is required.

Current Limiting:When driving an LED from a voltage source, an external current-limiting resistor is almost always required. The resistor value (R) can be calculated using Ohm's law: R = (V_{Power Supply}- V_F) / I_F. Use the maximum V from the datasheet_F(2.3V) to ensure sufficient current drive under all conditions. For example, to drive an LED from a 5V supply at 5mA: R = (5V - 2.3V) / 0.005A = 540 ohms. A standard 560-ohm resistor would be a safe choice.

Thermal Management:Although power consumption is low, continuous operation at high current (e.g., near the 30mA maximum) in high ambient temperatures will increase the junction temperature. This reduces light output and may affect long-term reliability. Ensure sufficient PCB copper area or thermal vias around the pads to aid heat dissipation, especially for designs using multiple LEDs or high drive currents.

Optical Design:A 130-degree viewing angle provides wide scattering. For applications requiring a more focused beam, secondary optics (e.g., a lens mounted above the PCB opening) are needed. The water-clear lens does not diffuse light internally, so the beam pattern will be defined by the chip geometry and the primary lens of the package.

9. Technical Comparison and Differentiation

The key differentiating feature of this component is itsReverse mountingConfiguration. Compared to standard top-emitting SMD LEDs, this design allows the PCB itself to act as a light guide and bezel, providing unique aesthetics and potentially saving vertical space behind the panel.

UsingAlInGaPSemiconductor technology is another significant advantage for orange/red light. Compared to older technologies such as Gallium Arsenide Phosphide (GaAsP), AlInGaP LEDs typically offer higher luminous efficiency and better temperature stability. This results in brighter, more consistent color output throughout the device's lifespan and across its operating temperature range.

Its compatibility with standardIR reflow soldering和Automatic placementIts compatibility makes it as easy to assemble as any other SMD component, minimizing production complexity despite its unique placement method.

10. Frequently Asked Questions (FAQ)

Q: What does "reverse mounting" mean?
A: Reverse mount LEDs are designed to be installed on the side of the PCB opposite the viewing surface. Light is emitted through a hole in the PCB, allowing the LED body to be hidden behind the panel for a seamless appearance.

Q: Can I drive this LED without a current-limiting resistor?
A: A'a. Haɗa LED kai tsaye zuwa tushen wutar lantarki da ya wuce ƙarfinsa na gaba zai haifar da wuce gona da iri na halin yanzu, yana lalata kayan aiki cikin sauri. Dole ne a yi amfani da resistor a jere ko direban halin yanzu na dindindin.

Q: Kewayon ƙarfin haske yana da faɗi (11.2 zuwa 71.0 mcd). Ta yaya zan san abin da zan samu?
A: Takamaiman ƙarfin yana ƙayyade ta lambobin rarrabuwa (L, M, N, P). Dole ne a ƙayyade rarrabuwar da ake buƙata lokacin yin oda. Idan ba a yi odar takamaiman rarrabuwa ba, kuna iya karɓar kowane rarrabuwa a cikin kewayon samfurin.

Q: Is this LED suitable for outdoor use?
A: The operating temperature range is -30°C to +85°C, covering many environments. However, the datasheet does not specify an IP rating for dust and water resistance. For outdoor use, additional sealing (such as conformal coating, gaskets) is required to protect the LED and its solder joints from moisture and contaminants.

Q: How to identify the anode and cathode?
A: Please refer to the package marking diagram in the datasheet. Typically, the cathode is marked. If in doubt, use the diode test mode of a multimeter; when forward biased (positive to anode, negative to cathode), the LED will glow faintly.

11. Practical Design Examples

Scenario:Design a status indicator light for the network router. The indicator should be a small orange dot on the front panel, flush with the surface.

1. PCB layout:On the component (bottom) side of the PCB, design the pad pattern using the pad dimensions recommended in the datasheet. On the top (user side), create a small opening aligned with the LED lens position in the solder mask and any overlay. The aperture should be slightly larger than the lens to avoid blocking the light.
2. Circuit design:The microcontroller of the router operates at 3.3V. To drive the LED conservatively at 5mA, calculate the series resistor: R = (3.3V - 2.3V) / 0.005A = 200 ohms. Use a standard 200-ohm or 220-ohm resistor, placed in series with the LED on the same PCB layer.
3. Assembly:The PCB is assembled using a standard lead-free reflow soldering process. The LED is automatically placed from a carrier tape reel onto the bottom pad. It is soldered into place during the reflow process.
4. Final Assembly:The PCB is installed into the router chassis. The front panel features a small window aligned with the PCB aperture. When powered on, an orange light emits through the aperture and the front panel window, creating a clean, modern indicator light.

12. Technical Principles

LED wani na'urar semiconductor ce da ke haskakawa ta hanyar wani tsari da ake kira electroluminescence. Lokacin da ake amfani da wani ƙarfin lantarki mai kyau a kan mahaɗin p-n, electrons daga yankin n-type da kuma ramuka daga yankin p-type ana shigar da su cikin yankin mai aiki. Sa’ad da waɗannan masu ɗaukar kaya suka haɗu, ana fitar da makamashi a cikin nau’in photon (haske). Takamaiman tsawon raƙuman hasken da ake fitarwa (launi) yana ƙayyade ta hanyar makamashin tazarar band na kayan semiconductor da ake amfani da su a yankin mai aiki.

Wannan takamaiman LED yana amfani daAluminum Indium Gallium Phosphide (AlInGaP)Compound semiconductors. By precisely controlling the proportions of aluminum, indium, gallium, and phosphorus during crystal growth, engineers can adjust the bandgap to efficiently generate light within the yellow, orange, and red spectral ranges. Compared to alternative materials for these colors, the AlInGaP material system is renowned for its high internal quantum efficiency and excellent high-temperature performance.

13. Industry Trends

The LED industry continues to advance towards higher efficiency, smaller size, and greater integration. For indicator-type LEDs like these, the trends include:

• Miniaturization:Develop smaller package sizes (e.g., 0402, 0201 metric) to save PCB space in increasingly compact devices.
• Higher Brightness at Lower Current:Chip design and material improvements allow for sufficient brightness at extremely low drive currents (e.g., 1-2 mA), thereby reducing overall system power consumption, which is crucial for battery-powered IoT devices.
• Improved color consistency:Tighter binning specifications and advanced manufacturing controls result in smaller variations in color and brightness within production batches, which is important for applications using multiple LEDs (e.g., light strips, arrays).
• Enhanced reliability:Continuous improvement of packaging materials (epoxy, silicone) to better withstand higher reflow soldering temperatures, harsher environmental conditions, and provide longer service life.
• Integrated Solutions:LEDs with built-in resistors or driver ICs are growing, simplifying circuit design by reducing the number of external components.

Reverse mounting configuration itself is part of a broader trend in consumer electronics and industrial electronics towards lighting solutions that are more aesthetically integrated and mechanically robust.