SMD LED LTST-008TGVFWT Datasheet - White Diffused Lens - Green/Orange Bicolor Light Source - 20-30mA - 68-84mW - Technical Documentation

1. Product Overview

This document details the specifications of a surface-mount device (SMD) LED that utilizes a white scattering lens and integrates two independent light-emitting sources within a single package. The device is specifically designed for automated printed circuit board (PCB) assembly processes and is suitable for critical applications with space constraints. Its compact form factor and compatibility with standard industry processes make it a versatile component in modern electronic products.

1.1 Features

• Compliant with the RoHS (Restriction of Hazardous Substances) directive.
• Packaged in 12mm carrier tape, wound on 7-inch diameter reels for automated handling.
• Compliant with EIA (Electronic Industries Alliance) standard package outline.
• Input compatible with Integrated Circuit (IC) logic levels.
• Designed for compatibility with automated surface-mount assembly equipment.
• Capable of withstanding the infrared (IR) reflow soldering process commonly used in surface-mount technology.
• 已进行预处理，加速达到JEDEC（联合电子设备工程委员会）湿度敏感等级3级，这意味着在密封袋打开后，在<30°C/60% RH条件下的车间寿命为168小时。

1.2 Applications

The dual-color function and diffused lens make this LED suitable for various indication and backlighting purposes. The main application areas include:

• Communication Equipment:Status indicators on routers, modems, and mobile phones.
• Office Automation:Taurari na wutar lantarki, haɗi, ko aiki akan firinta, na'urar sikan, da na'urar nuni.
• Kayan Aikin Gida:Taurari na panel iko akan microwave, na'urar wanki, da tsarin sauti.
• Kayan Aikin Masana'antu:Nuni na yanayin inji ko kuskure akan panel iko.
• Alama da Nuni na Ciki:Hasken ƙarancin haske ko mai nuna launi a cikin allon bayanai.

2. Detailed Technical Specifications

This section provides a detailed and objective analysis of the electrical, optical, and thermal characteristics of the device. Understanding these parameters is crucial for reliable circuit design and achieving the intended performance.

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 design.

• Power Dissipation (P_D):68 mW for the green chip, 84 mW for the orange chip. This is the maximum power the LED can dissipate as heat when the ambient temperature (T_a) is 25°C.
• Peak Forward Current (I_FP):Both colors are rated at 80 mA. This is the maximum current allowed under pulse conditions (1/10 duty cycle, 0.1ms pulse width). It is significantly higher than the DC rating and is suitable for brief, high-intensity flashes.
• DC Forward Current (I_F):Green is 20 mA, orange is 30 mA. This is the maximum continuous current recommended for reliable long-term operation.
• Operating Temperature Range:-40°C to +85°C. The device is guaranteed to operate normally within this ambient temperature range.
• Storage Temperature Range:-40°C to +100°C. The device can be stored unpowered within this range.

2.2 Electrical and Optical Characteristics

These are at T_a=25°C under specified test conditions. They are used for design calculations and performance expectations.

• Luminous flux (Φ_v):Total visible light output measured in lumens (lm).
  • Green light (I_F=5mA): minimum 0.95 lm, maximum 2.30 lm.
  • Orange light (I_F=20mA): minimum 1.25 lm, maximum 3.75 lm.
• Luminous intensity (I_v):Light output in a specific direction, measured in millicandelas (mcd). This is a reference value measured using a CIE human eye response filter.
  • Green light (I_F=5mA): minimum 330 mcd, maximum 775 mcd.
  • Orange light (I_F=20mA): Minimum 450 mcd, maximum 1350 mcd.
• Viewing Angle (2θ_1/2):Approximately 130 degrees (typical). This is the full angle at which the luminous intensity is half of the axial (0 degrees) measurement. The white diffused lens creates a wide, uniform viewing pattern.
• Peak Emission Wavelength (λ_P):The wavelength at which the spectral output is strongest.
  • Green: 518 nm (typical).
  • Orange: 611 nm (typical).
• Dominant Wavelength (λ_d):The single wavelength that best represents the perceived color.
  • Green light: Range from 527 nm to 537 nm, binned (see Section 3).
  • Orange light: 605 nm (typical).
• Spectral line half-width (Δλ):The bandwidth of the emission spectrum at half of its maximum intensity.
  • Green light: 35 nm (typical).
  • Orange light: 20 nm (typical). Orange light sources have a narrower, purer spectral output.
• Forward Voltage (V_F):Voltage drop across the LED when operating at the specified current.
  • Green light (I_F=5mA): Min 2.4V, Max 3.4V.
  • Orange light (I_F=20mA): Min 1.8V, Max 2.8V.
  • According to the note, the tolerance is +/- 0.1V.
• Reverse Current (I_R):At V_R=5V, Max 10 μA. This device is not designed for reverse bias operation; this parameter is for IR test reference only.

3. Binning System Description

To ensure color and brightness consistency in production, LEDs are sorted into different bins based on key parameters. This device uses a combined binning system.

3.1 Rarraba Ƙarfin Haskakawa (I_V)

Ana raba LED bisa ga fitowar haskensu a daidai gwargwadon ƙayyadaddun igiyar gwaji.

Hasken kore (@ 5mA):
G1: 0.95-1.26 lm (330-440 mcd)
G2: 1.26-1.70 lm (440-585 mcd)
G3: 1.70-2.30 lm (585-775 mcd)

Hasken lemu (@ 20mA):
O1: 1.25-1.80 lm (450-650 mcd)
O2: 1.80-2.60 lm (650-930 mcd)
O3: 2.60-3.75 lm (930-1350 mcd)

The tolerance for each luminous intensity grade is +/- 11%.

3.2 Green Dominant Wavelength (WD) Binning

Wavelength grading is applied only to green light sources to control hue variation.
AQ: 527 - 532 nm
AR: 532 - 537 nm
The tolerance for each grade is +/- 1 nm.

3.3 Composite Binning Code

The single alphanumeric code on the product label combines two luminous intensity bins. For example, code "A1" corresponds to green light G1 bin and orange light O1 bin. This cross-reference table (A1-A9) allows precise selection of brightness combinations for two colors within the same package.

4. Mechanical and Packaging Information

4.1 Device Dimensions and Pin Configuration

The SMD package has specific pad dimensions critical for PCB layout. Unless otherwise specified, all dimensions are in millimeters with a standard tolerance of ±0.2 mm. The pin assignment for LTST-008TGVFWT is as follows: Pins (0,1) and 2 are assigned to the green (InGaN) light source. Pins 3 and 4 are assigned to the orange (AlInGaP) light source. Pins 5, 6, and 7 are No Connect (NC). Designers must refer to the detailed dimension drawings in the original datasheet for accurate pad pitch, component height, and lens dimensions to ensure proper mounting and soldering.

4.2 Recommended PCB Solder Pads

Recommended pad patterns (land patterns) are provided to ensure reliable solder joint formation during reflow soldering. Using this pattern helps achieve proper solder fillets, mechanical stability, and heat dissipation. The pad design considers solder mask and solder paste application.

4.3 Carrier Tape and Reel Packaging

Components are supplied in embossed carrier tape for automated assembly. Key packaging specifications include:
- Carrier tape width: 12 mm.
- Reel diameter: 7 inches.
- Quantity per reel: 4000 pieces.
- Minimum order quantity remainder: 500 pieces.
- Packaging complies with ANSI/EIA-481 specification.
- The carrier tape is covered and sealed to protect components, allowing a maximum of two consecutive empty pockets.

5. Soldering and Assembly Guide

5.1 Infrared Reflow Soldering Profile

This device is compatible with lead-free (Pb-free) soldering processes. A recommended infrared reflow profile compliant with J-STD-020B is provided. Key parameters include:
- Preheat Temperature:150-200°C.
- Preheat Time:Maximum 120 seconds.
- Peak Package Body Temperature:Maximum 260°C.
- Time above liquidus:Control should be based on the graph to ensure proper solder joint formation while avoiding thermal damage to the LED.

5.2 Hand Soldering (If Necessary)

If manual rework is required:
- Soldering iron temperature: Max. 300°C.
- Soldering time per pad: Max. 3 seconds.
- Important: Hand soldering should be limited to a single attempt to prevent excessive thermal stress.

5.3 Storage and Handling

Sealed packaging:Store at ≤30°C and ≤70% relative humidity (RH). The shelf life is one year when stored in the original moisture barrier bag with desiccant.
Opened packaging:For components removed from sealed bags, the storage environment should not exceed 30°C and 60% RH. It is strongly recommended to complete the infrared reflow soldering process within 168 hours (1 week) after exposure. For storage exceeding 168 hours, components should be rebaked at approximately 60°C for at least 48 hours before soldering to remove absorbed moisture and prevent the "popcorn" effect during reflow.

5.4 Cleaning

If post-weld cleaning is required, use only approved solvents. Immersing the LED in ethanol or isopropyl alcohol at room temperature for less than one minute is acceptable. Do not use unspecified chemical cleaners, as they may damage the epoxy lens or package.

6. Application Notes and Design Considerations

6.1 Current Limiting

An external current-limiting resistor must be used to drive an LED. The resistor value (R) can be calculated using Ohm's Law: R = (V_supply- V_F) / I_F. For conservative design, always use the maximum V_Ffrom the datasheet to ensure the current does not exceed the required I_F. For a green LED (V_{F_max}=3.4V @5mA) with a 5V supply: R = (5V - 3.4V) / 0.005A = 320Ω. A standard 330Ω resistor is suitable. For pulsed operation at peak current (80mA), ensure the drive circuit can safely deliver the required pulse.

6.2 Thermal Management

Although SMD LEDs are efficient, they still generate heat. Exceeding the maximum junction temperature will reduce light output and lifespan. Precautions:
- Do not exceed the absolute maximum power dissipation (68/84 mW).
- Ensure the PCB pad design provides sufficient heat dissipation, especially when operating at high ambient temperatures or near maximum current.
- Avoid placing other heat-generating components nearby.

6.3 Optical Design

The white diffuser lens provides a wide, Lambertian-like emission pattern (130° viewing angle). This is ideal for applications requiring wide-angle visibility without secondary optics. For directional light, external lenses or light guides are needed. When both color chips are illuminated, the diffuser lens also helps mix light from the two discrete color chips for a more uniform appearance.

7. Technical Comparison and Differentiation

The device offers specific advantages in particular application scenarios:
Compared to monochrome SMD LEDs:The primary advantage is the integration of two distinct colors (green and orange) within a single package. Compared to using two separate LEDs, this saves PCB space, reduces component count, and simplifies assembly. It enables dual-status indication from a single point (e.g., green for "ON/Normal," orange for "Standby/Warning").
Compared to RGB LEDs:This is not an RGB LED. It provides only two specific, saturated colors (green and orange), potentially offering higher efficiency and a simpler two-channel drive circuit compared to a three-channel RGB driver. It is a solution for applications specifically requiring only these two indicator colors.
Key Differentiators:将White diffuser lens与Colored chip light sourceThe combination is noteworthy. Compared to transparent lenses that may show distinct chip images, scattering lenses soften the appearance of discrete light-emitting chips, creating a more uniform and aesthetically pleasing illuminated area.

8. Frequently Asked Questions (Based on Technical Parameters)

Q1: Can I drive the green and orange LEDs at their maximum DC current simultaneously?
A: The datasheet provides ratings for each color source. The power dissipation ratings (68mW for green, 84mW for orange) are independent. Therefore, you can drive both at their respective maximum I_F(20mA for green, 30mA for orange) simultaneously, provided the package and PCB can dissipate the total heat generated. Typically, derating and operating below absolute maximum ratings is good practice for enhanced reliability.

Q2: Why are the test currents different for the green (5mA) and orange (20mA) light sources?
A: This reflects the typical operating points chosen to achieve the target brightness levels and efficiency for each semiconductor material (InGaN for green, AlInGaP for orange). The specified luminous intensity values are valid only at these test currents. Interpolating or extrapolating performance to other currents requires reference to the typical characteristic curves.

Q3: What does "binning" mean for my design?
A: Binning yana tabbatar da daidaito. Idan zaninku yana buƙatar takamaiman launin kore ko mafi ƙarancin haske, dole ne ku ƙayyade lambar binning da ta dace (misali, AR yana nufin tsawon raƙuman kore, G3/O3 yana nufin mafi girman haske). Don aikace-aikacen da ba su da ƙarfi sosai, faɗin binning ko "kowane" bin na iya zama abin karɓa, wanda zai iya rage farashi.

Q4: Ana buƙatar diode na kariya ta baya?
A: Takaddun ƙayyadaddun bayanai sun bayyana cewa na'urar ba a ƙirƙira ta don aiki na baya ba, kuma sun ƙayyade kwararar baya (I_R) kawai don gwajin tunani. A cikin da'irori inda za a iya samun saurin canjin ƙarfin lantarki na baya (misali, nauyin inductive, cirewa mai zafi), ana ba da shawarar amfani da kariya ta waje, kamar haɗa diode a jere tare da LED ko a layi daya tare da diode TVS, don hana lalacewa.

9. Practical Design Case Studies

Yanayi:Zana alamar yanayin don mai sauya hanyar sadarwa. Bukatu: Alamar da za ta iya nuna jihohi uku: kashewa (babu haɗi), kore mai dorewa (haɗin 1 Gbps), walƙiya orange (aikin haɗin 100 Mbps).
Aiwatarwa ta amfani da LTST-008TGVFWT:
1. PCB kunshe:Amfani da shafin gwangwani da aka ba da shawarar. Karkatar da igiyoyin zuwa allurar haske mai kore (misali, fil 0,1) da haske mai ruwan lemo (fil 3,4).
2. Da'irar turawa:Amfani da fil biyu na GPIO na microcontroller. Kowane fil yana turawa transistor ko tashar turawa ta LED ta musamman. Yi lissafin resistor mai iyakancewar kwarara don haske mai kore (manufa ~5-10mA) da haske mai ruwan lemo (manufa ~15-20mA) daban.
3. Firmware:Control status: GPIO_Green=HIGH for steady green; GPIO_Orange toggles via timer for blinking orange.
4. Advantages:Saves space compared to two separate LEDs. The diffuser lens creates a clean, uniform indication point. Distinct green and orange colors are easy to differentiate.

10. Working Principle

A light-emitting diode (LED) is a semiconductor device that emits light through electroluminescence. When a forward voltage is applied across the p-n junction, electrons from the n-type material recombine with holes from the p-type material. This recombination releases energy in the form of photons (light). The specific wavelength (color) of the emitted light is determined by the energy band gap of the semiconductor material used.
-Green LightGenerated by indium gallium nitride (InGaN) semiconductor. Its energy band gap corresponds to photons in the green wavelength region (~518-537 nm).
-Orange LightGenerated by aluminum indium gallium phosphide (AlInGaP) semiconductor, which has a small band gap and is suitable for orange/red wavelengths (~605-611 nm).
该White diffuser lensMade from epoxy or silicone materials doped with scattering particles. It does not change the color but spatially diffuses light from the small, bright semiconductor chip, creating a broader, more uniform, and less glaring emission pattern.

11. Technology Trends

The SMD LED field continues to evolve. General trends observable in the industry that provide context for devices like this one include:
Efficiency Improvement:Ongoing improvements in material science and chip design lead to higher lumens per watt (lm/W), enabling brighter output at lower currents or reduced power consumption.
Miniaturization:The drive for smaller end products is pushing LED package sizes to continuously shrink (e.g., from 0603 to 0402 to 0201 metric sizes) while maintaining or improving optical performance.
Enhanced Color Mixing and Control:Multi-chip packages (like this bicolor LED) are becoming more sophisticated, ensuring color consistency through tighter binning and integrating drivers for better color mixing in RGB or tunable white applications.
Improved Reliability and Thermal Performance:Advances in packaging materials (such as high-temperature silicones and ceramic substrates) enhance the ability to withstand higher reflow temperatures and improve long-term lumen maintenance, especially for high-power applications.
Smart Integration:A growing trend is the integration of control circuitry (like constant current drivers or simple logic) into the LED package itself, simplifying system design for the end user.