SMD LED 22-21/GHC-YR1S2/2C Datasheet - Brilliant Green - 2.2x2.1mm - 3.3V - 20mA - English Technical Document

1. Product Overview

The 22-21/GHC-YR1S2/2C is a surface-mount device (SMD) LED designed for modern, compact electronic applications. This brilliant green LED is built using InGaN chip technology and is encapsulated in a water-clear resin. Its primary advantage lies in its miniature footprint, which enables significant reductions in printed circuit board (PCB) size, allows for higher component packing density, and contributes to the overall miniaturization of end-user equipment. The lightweight nature of the package further makes it ideal for portable and space-constrained applications.

The product is fully compliant with contemporary environmental and manufacturing standards. It is lead-free (Pb-free), adheres to the RoHS directive, complies with EU REACH regulations, and meets halogen-free requirements (Br <900 ppm, Cl <900 ppm, Br+Cl < 1500 ppm). It is supplied in industry-standard 8mm tape on 7-inch diameter reels, making it fully compatible with automated pick-and-place assembly equipment and suitable for both infrared and vapor phase reflow soldering processes.

2. Technical Specifications

2.1 Absolute Maximum Ratings

The following ratings define the limits beyond which permanent damage to the device may occur. Operation under or at these conditions is not guaranteed and should be avoided for reliable performance.

• Reverse Voltage (V_R): 5 V
• Continuous Forward Current (I_F): 25 mA
• Peak Forward Current (I_FP): 100 mA (Duty Cycle 1/10 @ 1 kHz)
• Power Dissipation (P_d): 95 mW
• Electrostatic Discharge (ESD) Human Body Model (HBM): 150 V
• Operating Temperature Range (T_opr): -40 °C to +85 °C
• Storage Temperature Range (T_stg): -40 °C to +90 °C
• Soldering Temperature (T_sol): Reflow: 260 °C for 10 seconds max; Hand Soldering: 350 °C for 3 seconds max.

2.2 Electro-Optical Characteristics

These parameters are measured at an ambient temperature (T_a) of 25 °C and a standard forward current (I_F) of 20 mA, unless otherwise specified. They define the typical performance of the LED.

• Luminous Intensity (I_v): Minimum 112 mcd, Typical value not specified, Maximum 285 mcd. Tolerance: ±11%.
• Viewing Angle (2θ_1/2): 130 degrees (typical).
• Peak Wavelength (λ_p): 518 nm (typical).
• Dominant Wavelength (λ_d): Minimum 520 nm, Maximum 535 nm. Tolerance: ±1 nm.
• Spectral Bandwidth (Δλ): 35 nm (typical).
• Forward Voltage (V_F): Minimum 2.7 V, Typical 3.3 V, Maximum 3.7 V at I_F=20mA.
• Reverse Current (I_R): Maximum 50 μA at V_R=5V.

3. Binning System

To ensure color and brightness consistency in production, the LEDs are sorted into bins based on luminous intensity and dominant wavelength.

3.1 Luminous Intensity Binning

LEDs are categorized into four intensity ranks (R1, R2, S1, S2) measured at I_F = 20 mA.

• R1: 112 mcd to 140 mcd
• R2: 140 mcd to 180 mcd
• S1: 180 mcd to 225 mcd
• S2: 225 mcd to 285 mcd

3.2 Dominant Wavelength Binning

LEDs are categorized into three wavelength ranks (X, Y, Z) measured at I_F = 20 mA.

• X: 520 nm to 525 nm
• Y: 525 nm to 530 nm
• Z: 530 nm to 535 nm

4. Performance Curve Analysis

The datasheet provides several characteristic curves that are crucial for circuit design and thermal management. These graphs illustrate the relationship between key parameters under varying conditions.

• Relative Luminous Intensity vs. Ambient Temperature: This curve shows how light output decreases as the junction temperature rises. Designers must account for this derating in high-temperature environments.
• Relative Luminous Intensity vs. Forward Current: This graph demonstrates the non-linear relationship between drive current and light output. Operating above the recommended current leads to diminished efficiency and accelerated aging.
• Forward Voltage vs. Forward Current: The IV curve is essential for selecting the appropriate current-limiting resistor. The typical V_F of 3.3V at 20mA is a key design parameter.
• Forward Current vs. Ambient Temperature: This derating curve indicates the maximum allowable forward current as a function of the ambient temperature to stay within the power dissipation limits.

5. Mechanical and Package Information

5.1 Package Outline Dimensions

The 22-21 SMD LED has a compact rectangular package. The nominal dimensions are 2.2 mm in length and 2.1 mm in width, with a height typically around 1.0-1.2 mm (exact height should be confirmed from the dimensional drawing). The package features two anode/cathode terminals on the bottom. All unspecified tolerances are ±0.1 mm. A suggested pad layout is provided for PCB design, but engineers are advised to modify it based on their specific assembly process and thermal requirements.

5.2 Polarity Identification

The cathode is typically marked, often by a green dot, a notch in the package, or a chamfered corner. Correct polarity must be observed during assembly to prevent reverse bias damage.

6. Soldering and Assembly Guidelines

6.1 Reflow Soldering Profile

A lead-free (Pb-free) reflow profile is recommended:

• Pre-heating: 150–200°C for 60–120 seconds.
• Time Above Liquidus (217°C): 60–150 seconds.
• Peak Temperature: 260°C maximum, held for a maximum of 10 seconds.
• Heating Rate: Maximum 6°C/second.
• Time Above 255°C: Maximum 30 seconds.
• Cooling Rate: Maximum 3°C/second.

6.2 Hand Soldering

If hand soldering is necessary, extreme care must be taken. The soldering iron tip temperature should be below 350°C, and contact time with each terminal should not exceed 3 seconds. Use a low-power iron (≤25W) and allow a cooling interval of at least 2 seconds between soldering each terminal. Avoid applying mechanical stress to the LED body during heating.

6.3 Storage and Handling

The LEDs are packaged in moisture-sensitive barrier bags with desiccant.

• Before Opening: Store at ≤30°C and ≤90% Relative Humidity (RH).
• After Opening (Floor Life): 1 year at ≤30°C and ≤60% RH. Unused parts should be resealed in the moisture-proof bag.
• Baking: If the desiccant indicator changes color or the storage time is exceeded, bake at 60 ±5 °C for 24 hours before use.

7. Packaging and Ordering Information

7.1 Tape and Reel Specifications

The product is supplied in embossed carrier tape with a width of 8 mm, wound on a standard 7-inch (178 mm) diameter reel. Each reel contains 2000 pieces. Detailed reel and carrier tape dimensions are provided for compatibility with automated feeders.

7.2 Label Information

The reel label contains critical information for traceability and correct application:

• CPN: Customer's Product Number
• P/N: Manufacturer's Product Number (e.g., 22-21/GHC-YR1S2/2C)
• QTY: Packing Quantity
• CAT: Luminous Intensity Rank (e.g., S2)
• HUE: Chromaticity/Dominant Wavelength Rank (e.g., Y)
• REF: Forward Voltage Rank
• LOT No: Manufacturing Lot Number

8. Application Notes and Design Considerations

8.1 Typical Applications

This LED is suitable for a wide range of low-power indicator and backlighting functions:

• Telecommunications: Status indicators and keypad backlighting in telephones and fax machines.
• Consumer Electronics: Flat backlighting for small LCD panels, backlighting for switches and symbols on control panels.
• General Purpose Indication: Power status, mode indication, and other visual feedback in various electronic devices.

8.2 Critical Design Considerations

Current Limiting is Mandatory: An external current-limiting resistor must always be used in series with the LED. The forward voltage has a negative temperature coefficient and a tight tolerance range. A slight increase in supply voltage can cause a large, potentially destructive increase in forward current if not properly limited. The resistor value can be calculated using Ohm's Law: R = (V_supply - V_F) / I_F. Always use the maximum V_F from the datasheet for a conservative design.

Thermal Management: While the power dissipation is low, ensuring adequate PCB copper area around the LED pads helps dissipate heat, maintaining luminous output and longevity, especially in high ambient temperature conditions.

ESD Protection: Although rated for 150V HBM, standard ESD handling precautions should be followed during assembly and handling.

8.3 Application Restrictions

This component is designed for commercial and general industrial applications. It is not specifically qualified or guaranteed for use in high-reliability or safety-critical systems such as military/aerospace equipment, automotive safety systems (e.g., airbags, braking), or life-support medical equipment. For such applications, components with appropriate qualifications and reliability data should be sourced.

9. Technical Comparison and Positioning

The 22-21 package represents a balance between miniaturization and ease of handling. Compared to larger leaded LEDs (e.g., 3mm or 5mm), it offers a dramatically smaller footprint and is suited for automated assembly. Compared to smaller chip-scale packages (CSP), it provides better handling characteristics for standard SMT processes and often has a more defined viewing angle due to its molded lens. The brilliant green color, achieved with InGaN technology, offers higher luminous efficiency and better color saturation compared to older technologies like GaP, making it ideal for vivid indicator applications.

10. Frequently Asked Questions (FAQ)

Q: What is the difference between peak wavelength and dominant wavelength?
A: Peak wavelength (λ_p) is the wavelength at which the spectral power distribution is maximum. Dominant wavelength (λ_d) is the single wavelength of monochromatic light that matches the perceived color of the LED. λ_d is more relevant for color specification.

Q: Can I drive this LED without a resistor if my power supply is exactly 3.3V?
A: No. This is extremely dangerous. The forward voltage varies from unit to unit (2.7V to 3.7V) and decreases with temperature. A 3.3V supply could easily overdrive an LED with a low V_F, leading to rapid failure. Always use a series resistor.

Q: How do I interpret the bin codes (e.g., S2/Y) when ordering?
A> The bin code specifies the performance grade. \"S2/Y\" means the LED is from the highest luminous intensity bin (225-285 mcd) and the middle dominant wavelength bin (525-530 nm). Specifying bins allows for tighter consistency in your product's appearance.

Q: Is cleaning after soldering required?
A: The water-clear resin is generally resistant to common cleaning solvents, but compatibility should be verified. Avoid ultrasonic cleaning as it may damage the internal wire bonds.

11. Design and Usage Case Study

Scenario: Designing a Status Indicator for a Portable Device
A designer is creating a compact Bluetooth speaker. A bright, reliable power-on indicator is needed. The 22-21 brilliant green LED is selected for its small size and high visibility.
Design Steps:
1. The device uses a 5V USB power rail.
2. Target forward current (I_F) is set to 15 mA for a balance of brightness and power consumption.
3. Using the maximum V_F of 3.7V for a conservative design: R = (5V - 3.7V) / 0.015A = 86.7 Ω. The nearest standard value of 91 Ω is selected.
4. Power in the resistor: P = I²R = (0.015)² * 91 = 0.0205 W. A standard 1/10W or 1/8W resistor is sufficient.
5. The PCB layout includes modest thermal relief pads connected to a small ground plane for heat dissipation.
6. The BOM specifies the LED with bin code \"S1/Y\" to ensure consistent bright green color across all production units.
This approach ensures a robust, long-lasting indicator that meets the aesthetic and functional requirements of the product.

12. Operating Principle

This LED is a semiconductor photonic device. It is based on an Indium Gallium Nitride (InGaN) chip. When a forward voltage exceeding the diode's junction potential is applied, electrons and holes are injected into the active region from the n-type and p-type semiconductor layers, respectively. These charge carriers recombine, releasing energy in the form of photons (light). The specific composition of the InGaN alloy determines the bandgap energy, which directly defines the wavelength (color) of the emitted light—in this case, brilliant green around 518-535 nm. The water-clear epoxy resin encapsulant protects the chip, acts as a lens to shape the light output into a 130-degree viewing angle, and may contain phosphors or diffusers (though for this mono-color type, it is likely clear).

13. Technology Trends

The 22-21 package is part of a long-term industry trend towards miniaturization, increased efficiency, and improved manufacturability in optoelectronics. The use of InGaN materials for green LEDs represents a significant advancement over older technologies, offering higher efficiency and better color stability. Future developments in this class of device may focus on further increasing luminous efficacy (lumens per watt), improving color rendering for broader spectrum applications, and enhancing reliability under higher temperature and humidity conditions. The drive for halogen-free and environmentally friendly materials will continue to be a strong regulatory and market influence. Integration with intelligent drivers for dimming and color control is also a growing area, though typically implemented at the system level rather than within the discrete LED package itself.