Dual Color SMD LED LTST-C235TBKFWT Datasheet - Package Dimensions - Blue/Orange - 3.3V/2.0V - 76mW/75mW - English Technical Document

1. Product Overview

LTST-C235TBKFWT shine-shine, sit-on-top light (SMD) LED make for new-time electric thing use that need small, strong, bright show-light answer. It join two different inside-rock chip in one EIA-rule house: InGaN (Indium Gallium Nitride) chip for blue light and AlInGaP (Aluminum Indium Gallium Phosphide) chip for orange light. This way let one piece place can do many-many sign-work and state-show.

The thing call green thing, meet ROHS (Restriction of Hazardous Substances) follow-rule, make it good for use in sell-place with strong world-care law. It put in 8mm tape on 7-inch round roll, help fast machine pick-and-put-together work that many-many electric make-place use.

1.1 Heart Good-side and Strong-side

• Dual Color Source: Combines blue (InGaN) and orange (AlInGaP) light emission from separate chips.
• High Brightness: Utilizes ultra-bright chip technology for strong luminous intensity.
• Manufacturing Compatibility: Fully compatible with automatic placement equipment and standard infrared (IR) reflow soldering processes.
• IC Compatibility: Can be driven directly by most logic-level outputs.
• Standardized Packaging: EIA standard package ensures broad compatibility with industry designs and assembly lines.

2. Technical Parameter Analysis

This section provides a detailed, objective interpretation of the key electrical and optical parameters specified for the LTST-C235TBKFWT LED. All values are specified at an ambient temperature (Ta) of 25°C.

2.1 Absolute Maximum Ratings

These ratings define the limits beyond which permanent damage to the device may occur. Operation under these conditions is not guaranteed.

• Power Dissipation (Pd): Blue: 76 mW, Orange: 75 mW. This is the maximum power the LED can dissipate as heat under DC operation.
• Peak Forward Current (I_FP): Blue: 100 mA, Orange: 80 mA. This is the maximum allowable instantaneous current under pulsed conditions (1/10 duty cycle, 0.1ms pulse width). Exceeding this can cause catastrophic failure.
• DC Forward Current (I_F): Blue: 20 mA, Orange: 30 mA. This is the recommended maximum continuous forward current for reliable long-term operation.
• Temperature Ranges: Operating: -20°C to +80°C; Storage: -30°C to +100°C.
• Soldering Condition: Withstands infrared reflow soldering at a peak temperature of 260°C for 10 seconds.

2.2 Electrical & Optical Characteristics

These are the typical performance parameters under specified test conditions.

• Luminous Intensity (I_V): Measured in millicandelas (mcd) at I_F = 20 mA. Blue: Min. 18.0, Typ. 45.0, Max. 280.0. Orange: Min. 28.0, Typ. value not stated, Max. not applicable from table. This indicates the perceived brightness of the LED to the human eye.
• Viewing Angle (2θ_1/2): Yawanci digiri 130 ga duka launuka biyu. Wannan shine cikakken kusurwar da ƙarfin haske ya ragu zuwa rabin ƙimar sa akan-axis, yana ayyana yaduwar katako.
• Peak Wavelength (λ_P): Blue: 468 nm (Typ.), Orange: 611 nm (Typ.). Wannan shine tsayin raƙuman ruwa wanda fitarwar bakan ta fi ƙarfi.
• Dominant Wavelength (λ_d): Blue: 470 nm (Typ.), Orange: 605 nm (Typ.). Wannan shine tsayin raƙuman ruwa guda ɗaya wanda ya fi wakiltar launin da ake gani na LED, wanda aka samo daga zanen launi na CIE.
• Spectral Line Half-Width (Δλ): Blue: 25 nm (Typ.), Orange: 17 nm (Typ.). This measures the spectral purity or bandwidth of the emitted light.
• Forward Voltage (V_F): At I_F = 20 mA. Blue: Typ. 3.30V, Max. 3.80V. Orange: Typ. 2.00V, Max. 2.40V. This is the voltage drop across the LED when operating.
• Reverse Current (I_R): Max. 10 μA for both at V_R = 5V. The device is not designed for reverse bias operation; this parameter is for leakage characterization only.

3. Binning System Explanation

The luminous intensity of LEDs can vary from batch to batch. A binning system is used to sort LEDs into groups (bins) based on their measured performance, ensuring consistency for the end-user.

3.1 Luminous Intensity Binning

LTST-C235TBKFWT uses letter codes to denote intensity ranges. The tolerance within each bin is +/-15%.

Blue Chip Bins:
- M: 18.0 - 28.0 mcd
- N: 28.0 - 45.0 mcd
- P: 45.0 - 71.0 mcd
- Q: 71.0 - 112.0 mcd
- R: 112.0 - 180.0 mcd

Orange Chip Bins:
- N: 28.0 - 45.0 mcd
- P: 45.0 - 71.0 mcd
- Q: 71.0 - 112.0 mcd
- R: 112.0 - 180.0 mcd
- S: 180.0 - 280.0 mcd

This system allows designers to select a brightness grade suitable for their application's requirements, whether for high-ambient-light visibility or lower-power indication.

4. Performance Curve Analysis

While specific graphs are referenced in the datasheet (e.g., Fig.1, Fig.5), typical performance curves for such LEDs provide critical design insights.

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

The I-V relationship is exponential. For the blue chip (InGaN, V_F ~3.3V), the curve will have a steeper knee compared to the orange chip (AlInGaP, V_F ~2.0V). This necessitates different current-limiting resistor values when driving from the same voltage source to achieve the same target current (e.g., 20mA).

4.2 Luminous Intensity vs. Forward Current

Luminous intensity is approximately proportional to forward current within the recommended operating range. However, efficiency (light output per unit of electrical input) typically decreases at very high currents due to increased heat generation. Operating at or below the recommended DC forward current ensures optimal efficiency and longevity.

4.3 Temperature Dependence

LED performance is temperature-sensitive. As junction temperature increases:
- Luminous intensity generally decreases.
- Forward voltage typically decreases slightly for a given current.
- The dominant wavelength may shift (usually towards longer wavelengths).
Proper thermal management in the PCB design is crucial for maintaining consistent optical performance over the operating temperature range.

5. Mechanical & Package Information

5.1 Package Dimensions and Pin Assignment

The device conforms to an EIA standard SMD LED footprint. The specific dimensions are provided in the datasheet drawings. The pin assignment is critical for correct operation:
- Pins 1 and 2: Anode and Cathode for the Blue InGaN chip.
- Pins 3 and 4: Anode and Cathode for the Orange AlInGaP chip.
Consulting the package drawing is essential to identify the anode/cathode polarity for each color to avoid incorrect connection during PCB layout.

5.2 Recommended Solder Pad Design

The datasheet includes suggested solder pad dimensions. Following these recommendations ensures a reliable solder joint, proper alignment during reflow, and aids in heat dissipation from the LED package. Deviating significantly from these pad layouts can lead to tombstoning (component standing up), poor solder fillets, or reduced thermal performance.

6. Soldering & Assembly Guidelines

6.1 Reflow Soldering Profile

The datasheet provides a suggested IR reflow profile for lead-free (Pb-free) solder processes. Key parameters include:
- Pre-heat: 150-200°C to gradually heat the board and activate flux.
- Pre-heat Time: Maximum 120 seconds to prevent thermal shock.
- Peak Temperature: Maximum 260°C.
- Time Above Liquidus: The profile on page 3 shows the critical reflow zone; the component should be exposed to temperatures sufficient for solder melting (typically 217°C+ for SnAgCu) for an appropriate time (e.g., 60-90 seconds).
- Cooling Rate: Controlled cooling is recommended to minimize stress on solder joints.

6.2 Hand Soldering

If hand soldering is necessary:
- Yi amfani da guntun ƙarfe mai sarrafa zafin jiki da aka saita zuwa matsakaicin 300°C.
- Iyakance lokacin guntun ƙarfe zuwa matsakaicin dakika 3 a kowane haɗin gwiwa.
- Yi amfani da zafi a kan kushin PCB, ba kai tsaye ga jikin LED ba, don hana lalacewar zafi ga ruwan tabarau na filastik da mutuwar semiconductor.

6.3 Tsaftacewa

Idan ana buƙatar tsaftacewa bayan gudanar da aikin gini:
- Yi amfani da kayan tsaftacewa da aka ƙayyade kawai. Sinadarai da ba a ƙayyade ba na iya lalata ruwan tabarau na LED na epoxy, haifar da hazo ko fashewa.
- Abubuwan da aka ba da shawarar sune barasa na ethyl ko barasa na isopropyl a yanayin daki na yau da kullun.
- Lokacin nutsarwa ya kamata ya kasance ƙasa da minti ɗaya don hana shigar da abubuwan narkewa.

6.4 Ajiya da Gudanarwa

• ESD Precautions: LEDs are sensitive to electrostatic discharge (ESD). Use wrist straps, anti-static mats, and properly grounded equipment during handling.
• Moisture Sensitivity: As a surface-mount plastic package, it is moisture-sensitive. If the original sealed moisture-barrier bag is opened, the components should be used within one week or baked (e.g., at 60°C for 20 hours) before reflow to remove absorbed moisture and prevent "popcorning" damage during soldering.
• Long-term Storage: For opened packages, store at ≤30°C and ≤60% relative humidity. For extended storage, use a sealed container with desiccant.

7. Packaging and Ordering

7.1 Tape and Reel Specifications

The standard packaging is 8mm embossed carrier tape on 7-inch (178mm) diameter reels.
- Quantity per Reel: 3000 pieces.
- Minimum Order Quantity (MOQ): 500 pieces for remainder quantities.
- Cover Tape: Empty pockets are sealed with top cover tape.
- Missing Components: A maximum of two consecutive missing LEDs is allowed per the packaging standard (ANSI/EIA 481-1-A-1994).

8. Application Recommendations

8.1 Typical Application Scenarios

• Status Indicators: Dual-color capability allows for multiple statuses (e.g., blue for "on/standby," orange for "fault/charging," both for a third state).
• Consumer Electronics: Power buttons, connectivity status (Wi-Fi/Bluetooth), battery level indicators on laptops, routers, and peripherals.
• Industrial Control Panels: Machine status, operational mode indication.
• Automotive Interior Lighting: Low-power accent or indicator lighting, though specific automotive-grade qualification would be required.

8.2 Design Considerations

• Current Limiting: Always use a series resistor for each LED chip to set the forward current. Calculate resistor value as R = (V_source - V_F) / I_F. Use the maximum V_F from the datasheet for a conservative design that ensures I_F is not exceeded even with component variation.
• Driving Circuit: The LEDs are compatible with microcontroller GPIO pins. Ensure the GPIO can sink/source the required current (20-30mA). For higher currents or multiplexing many LEDs, use transistor drivers or dedicated LED driver ICs.
• Thermal Management: While power dissipation is low, ensure the PCB layout provides adequate copper area around the solder pads to act as a heat sink, especially if operating at high ambient temperatures or maximum current.
• Optical Design: The 130-degree viewing angle provides a wide, diffuse light pattern suitable for direct viewing. For light-piping applications, the wide angle helps couple light into the pipe effectively.

9. Technical Comparison and Differentiation

The LTST-C235TBKFWT offers specific advantages in its class:

• Dual-Chip vs. Single-Chip: Compared to using two separate single-color LEDs, this device saves PCB space, reduces component count, and simplifies assembly.
• Chip Technology: The use of InGaN for blue and AlInGaP for orange represents mature, high-efficiency semiconductor technologies for their respective colors, offering good brightness and reliability.
• Package Standardization: Paket standar EIA memastikan kompatibilitas langsung dengan berbagai jejak PCB dan pustaka desain yang ada, mengurangi risiko desain.
• Kompatibilitas Proses: Kompatibilitas penuh dengan IR reflow dan penempatan otomatis menjadikannya ideal untuk manufaktur volume tinggi yang sensitif terhadap biaya.

10. Frequently Asked Questions (FAQs)

Q1: Can I drive both the blue and orange LEDs simultaneously at their maximum DC current?
A1: Yes, but you must consider the total power dissipation. Simultaneous operation at 20mA (Blue) and 30mA (Orange) results in a power dissipation of approximately (3.3V*0.02A) + (2.0V*0.03A) = 0.126W. This is below the individual maximums but requires checking that the combined thermal load does not exceed the package's ability to dissipate heat in your specific layout.

Q2: Menene bambancin tsakanin tsayin zango mai kololuwa da tsayin zango mai rinjaye?
A2: Tsayin zango mai kololuwa (λ_P) shine tsayin zango na zahiri na madaidaicin madaidaicin ƙarfi a cikin bakan fitarwa. Tsayin zango mai rinjaye (λ_d) ƙima ce da aka ƙididdige bisa ga fahimtar launi na ɗan adam (taswirar CIE) wanda ke ayyana "launi" da muke gani. Ga LEDs masu launi guda ɗaya, galibi suna kusa. Ga LEDs masu faɗin bakan, suna iya bambanta.

Q3: Yaya za a fassara lambar bin lokacin yin oda?
A3: Lambar bin (misali, "P" don shuɗi, "Q" don lemu) tana ƙayyadaddun ƙayyadaddun madaidaicin ƙarfi mai haske da kewayon madaidaicin ƙarfi na wannan rukuni. Dole ne ku ƙayyade bin(s) da ake so lokacin yin oda don tabbatar da daidaiton haske a cikin samarwar ku. Idan ba a ƙayyade ba, za ku iya karɓar abubuwan da aka samo daga kowane bin da ke akwai a cikin gabaɗayan kewayon samfurin.

Q4: Shin wannan LED ya dace don amfani a waje?
A4: Oke ọwọ ọwọ ọwọ (-20°C si +80°C) fẹrẹ ọpọlọpọ awọn ipo ita. Sibẹsibẹ, igba pipẹ ita ifihan nilo iwadi awọn ohun afikun ti ko fẹrẹ ninu iwe data yii: UV igbẹkẹle ti awọn lens (lati ṣe idiwọ yellowing), igbẹkẹle si ọwọ ọwọ ayika, ati aabo lodi si omi wiwọle. Fun awọn ohun elo ita pataki, bẹwẹ olupilẹṣẹ fun itẹwọgba igbẹkẹle data tabi ro awọn ọja pataki ti o jẹ idaniloju fun ita lilo.

11. Apẹrẹ ati Lilo Case Iwadi

Scenario: Apẹrẹ a Dual-Status Agbara Bọtini fun a Network Switch
A designer needs an LED to indicate both power state (On/Off) and network activity (Active/Idle) on a single button.

Implementation:
1. The LTST-C235TBKFWT is placed behind a translucent button cap.
2. The microcontroller drives the LEDs:
- Solid Orange: Power is ON, device is booting/idle.
- Solid Blue: Power is ON, device is fully operational and idle.
- Blinking Blue: Power is ON, network activity is detected.
- Off: Power is OFF.
3. Current-limiting resistors are calculated separately for each color. For a 3.3V MCU rail: R_Blue = (3.3V - 3.3V) / 0.02A = 0Ω (theoretical). In practice, a small resistor (e.g., 10Ω) is used to limit inrush current and account for MCU pin voltage drop. R_Orange = (3.3V - 2.0V) / 0.02A = 65Ω (a 68Ω standard value is used).
4. The wide 130-degree viewing angle ensures the button is evenly illuminated from various viewing angles.

Outcome: A clean, compact user interface with clear, multi-state feedback using only one component footprint, simplifying PCB layout and assembly.

12. Technology Principle Introduction

Light Emission Principle: LEDs ni diodes za semiconductor. Wakati voltage ya mbele inatumika, elektroni huvuka makutano ya p-n na kujumuika tena na mashimo katika eneo lenye shughuli. Ujumuishaji huu hutoa nishati kwa njia ya fotoni (mwanga). Wavelength maalum (rangi) ya mwanga imedhamiriwa na nishati ya bandgap ya nyenzo ya semiconductor inayotumiwa.

Sayansi ya Nyenzo:
- InGaN (Indium Gallium Nitride): This material system allows for the tuning of the bandgap to produce light from ultraviolet through green and blue. The blue chip in this LED uses this technology.
- AlInGaP (Aluminum Indium Gallium Phosphide): This material system is used for high-brightness LEDs in the yellow, orange, and red spectrum. The orange chip in this LED uses this technology.

The combination of these two mature material technologies in one package provides a reliable solution for dual-color applications.

13. Industry Trends and Developments

The field of SMD LEDs continues to evolve. General trends relevant to components like the LTST-C235TBKFWT include:

• Increased Efficiency (lm/W): Ongoing improvements in epitaxial growth and chip design lead to higher luminous efficacy, meaning more light output for the same electrical input power.
• Miniaturization: While this product uses a standard package, the industry pushes for smaller footprints (e.g., 0402, 0201) for space-constrained applications like mobile devices.
• Improved Color Consistency: Tighter binning tolerances and advances in manufacturing control yield LEDs with more consistent chromaticity and brightness from batch to batch.
• Higher Reliability and Lifetime: Enhancements in packaging materials (epoxy, lead frames) and chip structures aim to extend operational lifetime and improve performance under high-temperature and high-humidity conditions.
• Integration: Beyond dual-color, there is a trend towards integrating more functions, such as RGB (Red, Green, Blue) LEDs in a single package, or even combining LEDs with control ICs (like driver or sequencer chips) into more complex modules.

LTST-C235TBKFWT yana wakiltar ingantaccen bayani, amintaccen mafita a cikin wannan yanayin da ke ci gaba, yana ba da daidaiton aiki, farashi, da kera don manyan aikace-aikacen nuna alamar launi biyu.