SMD LED 18-225A/R6GHW-B01/3T Datasheet - Package 3.2x1.6x1.3mm - Voltage 2.0V/3.3V - High Brightness Red/Green - Technical Documentation

1. Product Overview

The 18-225A series represents a compact, high-performance Surface Mount Device (SMD) LED solution. This datasheet covers two primary chip material variants: R6 (AlGaInP) for high-brightness red emission and GH (InGaN) for high-brightness green emission. The device is encapsulated in white diffused resin. Its core advantage lies in a significantly reduced footprint compared to traditional lead-frame type LEDs, thereby increasing packaging density on the PCB, reducing storage space requirements, and ultimately contributing to the miniaturization of end equipment. Its lightweight construction makes it particularly ideal for applications where space and weight are critical limiting factors.

2. In-depth Analysis of Technical Parameters

2.1 Absolute Maximum Ratings

Operating the device beyond these limits may cause permanent damage. Ratings are specified at an ambient temperature (Ta) of 25°C.

• Reverse Voltage (V_R):5 V (applies to both R6 and GH). Exceeding this value may cause junction breakdown.
• Forward Current (I_F):25 mA (continuous DC for R6 and GH).
• Peak forward current (I_FP):R6 is 60 mA, GH is 100 mA. This value is specified at a duty cycle of 1/10 and a frequency of 1 kHz, applicable for pulse operation.
• Power consumption (P_d):R6 is 60 mW, GH is 95 mW. This is the maximum allowable power that the package can dissipate without exceeding its thermal limits.
• Electrostatic discharge (ESD) human body model (HBM):R6 is 2000 V, GH is 150 V. The GH (InGaN) variant is more sensitive to ESD and requires stricter handling precautions.
• Operating Temperature (T_opr):-40°C to +85°C. This defines the ambient temperature range for reliable operation.
• Storage Temperature (T_stg):-40°C to +90°C.
• Welding temperature (T_sol):Reflow soldering: Peak temperature 260°C, maximum 10 seconds. Hand soldering: 350°C, maximum 3 seconds.

2.2 Electro-Optical Characteristics

These parameters are measured at Ta=25°C, standard test current I_FMeasured at =10mA unless otherwise specified. They define the LED's light output and electrical behavior.

• Luminous intensity (I_v):R6: 28.5 to 72.0 mcd (typ.). GH: 72.0 to 180 mcd (typ.). Under identical drive conditions, the GH chip produces a significantly higher luminous intensity.
• Viewing angle (2θ_1/2):130° (typical). This wide viewing angle is characteristic of the white diffused resin package, providing a near-Lambertian emission pattern suitable for area lighting and indicator applications.
• Peak Wavelength (λ_p):R6: 632 nm (typical). GH: 518 nm (typical). This is the wavelength at which the spectral power distribution reaches its maximum.
• Dominant Wavelength (λ_d):R6: 615-625 nm. GH: 520-535 nm. This is the single wavelength at which the human eye perceives the LED color. Tolerance is ±1nm.
• Spectral Radiant Bandwidth (Δλ):R6: 20 nm (typical). GH: 35 nm (typical). This indicates spectral purity; the smaller the bandwidth, the more saturated the color.
• Forward Voltage (V_F):R6: 1.7-2.4 V (typical 2.0V). GH: 2.7-3.7 V (typical 3.3V). The voltage drop is a function of the semiconductor material bandgap. Tolerance is ±0.10V.
• Reverse current (I_R):R6: Maximum 10 μA at V_R=5V. GH: Maximum 50 μA at V_R=5V.

3. Grading System Description

LEDs are sorted (binned) according to key optical parameters to ensure consistency within production batches and to meet design requirements.

3.1 Luminous Intensity Binning

R6 (Red):

• Grade N: 28.5 - 45.0 mcd
• Gear P: 45.0 - 72.0 mcd

GH (Green):

• Gear Q1: 72.0 - 90.0 mcd
• Gear Q2: 90.0 - 112 mcd
• Gear R1: 112 - 140 mcd
• Gear R2: 140 - 180 mcd

The luminous intensity tolerance is ±11%.

3.2 Dominant Wavelength Binning (GH Green only)

Green LEDs are further binned by dominant wavelength to control color consistency.

• Bin 1: 520 - 525 nm
• Bin 2: 525 - 530 nm
• Gear 3: 530 - 535 nm

The dominant wavelength tolerance is ±1nm.

4. Performance Curve Analysis

4.1 R6 (AlGaInP Red) Characteristics

The provided curves illustrate the key relationships:

• Forward Current vs. Forward Voltage (I-V Curve):It demonstrates an exponential relationship. The forward voltage increases with current and slightly decreases with rising temperature.
• Luminous Intensity vs. Forward Current:Within the normal operating range before saturation effects occur, the light output increases linearly with current.
• Luminous Intensity vs. Ambient Temperature:Light output decreases with increasing ambient temperature due to reduced internal quantum efficiency and increased non-radiative recombination. This derating is crucial for thermal management.
• Forward Current Derating Curve:It specifies the maximum allowable continuous forward current as a function of ambient temperature. Current must be reduced at higher temperatures to stay within power dissipation limits.
• Spectral Distribution:Shows an emission peak near 632 nm, with a typical bandwidth of 20 nm.
• Radiation Pattern:Describes the spatial intensity distribution, confirming a wide viewing angle of 130 degrees approaching a Lambertian pattern.

4.2 GH (InGaN Green) Characteristics

The GH curve shows a similar relationship but with different numerical values:

• Higher forward voltage (typical 3.3V, compared to 2.0V for R6).
• Luminous intensity and forward voltage have different temperature dependencies.
• The spectral center is around 518 nm, with a wider bandwidth of 35 nm.
• Due to their different power dissipation ratings (95 mW vs. 60 mW), they have different forward current derating curves.

5. Mechanical and Packaging Information

5.1 Package Dimensions

SMD package has the following key dimensions (unit: mm, tolerance ±0.1mm unless specified):

• Length: 3.2 mm
• Width: 1.6 mm
• Height: 1.3 mm ±0.2 mm
• Pin width: 0.4 mm ±0.15 mm
• Pin length: 0.7 mm ±0.1 mm
• Pin pitch: 1.6 mm

5.2 Polarity Identification and Pad Design

The cathode is marked. A recommended pad layout is provided with dimensions: pad width 0.8mm, length 0.8mm, and pad spacing 0.4mm. This is a suggestion; pad design should be optimized based on specific PCB fabrication processes and thermal requirements. The document emphasizes that pad dimensions can be modified according to individual needs.

6. Soldering and Assembly Guide

6.1 Welding Process

This device is compatible with infrared and vapor phase reflow processes. The lead-free reflow soldering profile is specified as follows:

• Preheat: 150-200°C, for 60-120 seconds.
• Time above liquidus (217°C): 60-150 seconds.
• Peak temperature: maximum 260°C.
• Time within ±5°C of peak temperature: maximum 10 seconds.
• Heating rate: up to 3°C per second.
• Cooling rate: up to 6°C per second.

Key Precautions:Reflow soldering should not exceed two times. Do not apply stress to the LED body during heating. The PCB should not warp after soldering.

6.2 Storage and Moisture-proof Requirements

Components are packaged in moisture barrier bags with desiccant.

• Before opening:Store at ≤30°C and ≤90% RH.
• After opening:Under conditions of ≤30°C and ≤60% RH, the "floor life" is 1 year. Unused components must be resealed in moisture barrier packaging.
• Baking:If the desiccant indicator changes color or the storage time is exceeded, bake at 60±5°C for 24 hours before use to remove absorbed moisture and prevent the "popcorn" effect during reflow soldering.

7. Packaging and Ordering Information

7.1 Reel and Carrier Tape Specifications

LEDs are supplied in 8mm wide embossed carrier tape, wound on 7-inch diameter reels. The quantity per reel is 3000 pieces. Detailed reel and tape dimensions are provided in the specification.

7.2 Label Description

Lakabin kwanon rufi ya ƙunshi lambobi da yawa:

• P/N: Lambar samfur (misali, 18-225A/R6GHW-B01/3T).
• QTY: Packaging Quantity.
• CAT: Luminous Intensity Grade (Binning Code, e.g., P, R1).
• HUE: Chromaticity coordinates and dominant wavelength grade (e.g., grade 2).
• REF: Forward voltage grade.
• LOT No: Traceable lot number.

8. Application Suggestions

8.1 Typical Application Scenarios

As listed in the specification:

• Backlighting for automotive dashboards and switches.
• Telecommunications equipment: status indicators and keyboard backlighting in telephones and fax machines.
• Flat backlighting for small LCDs, switches, and symbols.
• General indicator and status lights in consumer electronics, industrial control, and appliances.

8.2 Key Design Considerations

Current Limiting:An external current limiting resistor isabsolutely essential.. The forward voltage of an LED has a negative temperature coefficient and tight tolerance. A slight increase in the supply voltage can cause a large, potentially destructive increase in forward current. The resistor value must be selected based on the supply voltage (V_CC), and the typical forward voltage (V_F) and the required forward current (I_F) calculation: R = (V_CC- V_F) / I_F. Thermal management:Although it is a small SMD device, power dissipation (up to 95mW for GH) must be considered, especially at high ambient temperatures. Adhere to the forward current derating curve. Ensure sufficient PCB copper area (using thermal pad design) to conduct heat away from the LED junction.ESD Protection:Implement standard ESD handling procedures, especially for the more sensitive GH (InGaN) variants. If the LED is in a user-accessible area, consider using ESD protection devices on sensitive lines.

9. Technical Comparison and Differentiation

The 18-225A series offers significant advantages over larger through-hole LEDs in terms of PCB space and automated assembly compatibility. Within the realm of SMD LEDs, its primary differentiating features include:

• Wide Viewing Angle (130°):White diffused resin provides a very broad and uniform emission pattern, making it ideal for applications requiring wide-angle visibility rather than a focused beam.
• Dual-chip material options:Offering AlGaInP (R6) and InGaN (GH) within the same package size provides design flexibility for red/green indicator pairs or multi-color applications.
• Detailed binning:Multiple luminous intensity and wavelength bins are provided, enabling designers to select components for applications requiring strict brightness or color consistency.
• Robust Reflow Compatibility:Well-defined Pb-free reflow profiles and moisture handling information support modern, high-volume manufacturing processes.

10. Frequently Asked Questions (Based on Technical Parameters)

Q1: Can I drive this LED directly with a 5V or 3.3V logic power supply?A:No.You must always use a series current-limiting resistor. For example, to drive a green LED (V_F~3.3V), I_F=20mA with a 5V supply: R = (5V - 3.3V) / 0.020A = 85 ohms. Use the next standard value (e.g., 82 or 100 ohms) and verify the actual current and power dissipation.

Q2: Why does the green LED (GH) have a lower ESD rating than the red (R6)?A: This is a fundamental material property. InGaN-based LEDs (blue, green, white) typically have a lower ESD withstand voltage compared to AlGaInP-based LEDs (red, amber). This necessitates more careful handling for the green variants.

Q3: What does the "white diffused" resin color mean for light output?A: The diffuser resin scatters light emitted from the chip, creating a wider, more uniform viewing angle (130°) and giving the unpowered LED a white appearance. It softens the light output, making it less like a point source and more suitable for panel lighting.

Q4: How to interpret the binning codes when ordering?A: Specify the required CAT (luminance) and HUE (color of the green LED) binning codes based on your application's tolerance for brightness variation and color shift. For non-critical indicator lights, a wider binning may be acceptable and cost-effective. For backlight arrays where uniformity is critical, specifying tight binning is essential.

11. Design Case Studies

Scenario:Design a compact control panel with multi-state indicator lights.Requirements:Red indicates "Fault", green indicates "Ready". Space is extremely limited. The indicator lights must be clearly visible from a wide angle. The assembly process uses automated SMD placement and reflow soldering.Solution Implementation:

1. Component Selection:Red uses 18-225A/R6, green uses 18-225A/GH. The identical 3.2x1.6mm footprint simplifies PCB layout.
2. Circuit Design:For the 3.3V system power supply:
   • Red LED: R = (3.3V - 2.0V) / 0.010A = 130 ohms. Use a 130Ω or 120Ω resistor. Resistor power dissipation: (1.3V^2)/130Ω ≈ 13mW.
   • Green LED: R = (3.3V - 3.3V) / 0.010A = 0 ohms. This is problematic. The 3.3V supply is exactly at the typical V_Fvalue of the green LED, leaving no voltage headroom for the resistor. Solutions: a) Use a lower current (e.g., 5mA), b) Use a higher supply voltage for the LED circuit, or c) Use a constant current driver.
3. PCB layout:Place the LED near the edge of the panel. Use the recommended or slightly larger pads and connect them to a small copper pour for heat dissipation. Ensure the polarity marking on the silkscreen matches the cathode marking on the LED.
4. Manufacturing:Program the pick-and-place machine for a 3.2x1.6mm component size. Follow the specified reflow profile precisely. Store opened reels in a dry cabinet if not used immediately.
5. Grading:For this panel with multiple identical indicator lights, specify a single brightness grading (e.g., CAT P for red, CAT R1 for green) to ensure a consistent appearance across all units.

12. Introduction to Technical Principles

LED ni diode ya semiconductor inayotoa mwanga kwa njia ya umeme. Wakati voltage chanya inatumika kwenye mpaka wa p-n, elektroni na mashimo huingizwa kwenye eneo lenye uwezo, ambapo huchanganyika. Nishati inayotolewa wakati wa mchakato huu hutoa foton (mwanga). Rangi ya mwanga unaotolewa (urefu wa wimbi) imedhamiriwa na nishati ya pengo la bendi ya nyenzo ya semiconductor inayotumika katika eneo lenye uwezo.

• R6 (AlGaInP):Aluminium Gallium Indium Phosphide ni mfumo wa nyenzo unaotumika kutengeneza LED zenye ufanisi katika anuwai ya wigo nyekundu, machungwa na ya kahawia. Ina pengo la bendi la moja kwa moja linalofaa kwa utoaji wa mwanga wenye ufanisi.
• GH (InGaN):InGaN is the material system used for blue, green, and white LEDs. By altering the indium content, the bandgap can be tuned. Within this material system, achieving high-efficiency green light emission (the "green gap") has been a longstanding historical challenge.

Light from the tiny semiconductor chip is encapsulated within an epoxy or silicone package. The "white diffusive" resin contains scattering particles that randomize the direction of photons, resulting in a broad, uniform emission pattern. The package also provides mechanical protection, electrical contacts, and aids in heat dissipation.

13. Industry Trends

The SMD LED market continues to evolve, driven by demands for miniaturization, higher efficiency, and lower cost. Trends related to devices such as the 18-225A include:

• Efficiency Improvement:Ongoing advancements in epitaxial growth and chip design lead to higher luminous efficacy (more light output per watt of electrical power), enabling brighter indicator lights or lower power consumption.
• Improved Color Consistency:Advances in manufacturing control and more sophisticated binning strategies have enabled tighter color and brightness tolerances, which are crucial for applications such as backlight arrays and full-color displays.
• Color Gamut Expansion:The development of new phosphors and narrow-band emitters, such as quantum dots, has enabled LEDs to achieve more saturated colors, expanding the color space achievable by displays.
• Integration:The trend of integrating multiple LED chips (RGB, RGBW), control ICs, and even passive components into a single package module continues, simplifying the assembly of end products.
• Reliability Focus:As LEDs penetrate into automotive, industrial, and medical markets, increasing emphasis is placed on long-term reliability data, failure mode analysis, and certification under harsh environmental conditions (high temperature, high humidity, thermal cycling).

While newer, smaller package forms exist (e.g., 0201, 01005), the 3.2x1.6mm footprint remains a popular and reliable workhorse for general indicator and backlight applications, offering a good balance between size, brightness, ease of handling, and thermal performance.