SMD LED 22-21/BHC-AN1P2/2C Blue Datasheet - 2.2x2.1x1.1mm - 3.8V - 20mA - 40mW - English Technical Document

1. Product Overview

The 22-21/BHC-AN1P2/2C is a surface-mount device (SMD) light-emitting diode (LED) emitting blue light. It is designed for modern, compact electronic assemblies requiring reliable indicator or backlighting functionality. The device utilizes an InGaN (Indium Gallium Nitride) chip material encapsulated in a water-clear resin, producing light with a typical dominant wavelength of 468 nm.

The core advantage of this component lies in its miniature footprint. Measuring only 2.2mm x 2.1mm with a height of approximately 1.1mm, it enables significant reductions in printed circuit board (PCB) size and allows for higher packing density compared to traditional leaded LEDs. This miniaturization contributes directly to smaller end-product form factors and reduced storage requirements for components. The device is also lightweight, making it ideal for portable and miniature applications.

The product is compliant with key environmental and safety regulations, including being Pb-free (lead-free), adhering to the EU RoHS (Restriction of Hazardous Substances) directive, complying with EU REACH (Registration, Evaluation, Authorisation and Restriction of Chemicals) regulations, and meeting halogen-free standards (Bromine <900 ppm, Chlorine <900 ppm, Br+Cl < 1500 ppm). It is supplied in industry-standard 8mm tape on 7-inch diameter reels, ensuring compatibility with automated pick-and-place assembly equipment. The component is suitable for both infrared and vapor phase reflow soldering processes.

2. Technical Parameter Deep-Dive

2.1 Absolute Maximum Ratings

These 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 in circuit design.

• Reverse Voltage (V_R): 5 V - The maximum voltage that can be applied in the reverse-biased direction.
• Forward Current (I_F): 20 mA - The maximum continuous DC forward current recommended for reliable operation.
• Peak Forward Current (I_FP): 100 mA - The maximum pulsed forward current, permissible only under specific conditions (duty cycle of 1/10 at 1 kHz frequency).
• Power Dissipation (P_d): 40 mW - The maximum power the device can dissipate, calculated as the product of forward voltage and forward current, considering thermal limitations.
• Electrostatic Discharge (ESD) Human Body Model (HBM): 150 V - The device's sensitivity to electrostatic discharge. Proper ESD handling procedures are mandatory during assembly and handling.
• Operating Temperature (T_opr): -40°C to +85°C - The ambient temperature range over which the device is specified to operate.
• Storage Temperature (T_stg): -40°C to +90°C - The temperature range for storing the device when not powered.
• Soldering Temperature (T_sol): Two profiles are specified: Reflow soldering (260°C peak for a maximum of 10 seconds) and Hand soldering (350°C at the iron tip for a maximum of 3 seconds per terminal).

2.2 Electro-Optical Characteristics

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

• Luminous Intensity (I_v): Ranges from a minimum of 28.5 mcd to a maximum of 72.0 mcd. The typical value is not specified in the table, but the binning system provides categorized ranges. The viewing angle (2θ_1/2) is typically 130 degrees, indicating a wide viewing cone.
• Peak Wavelength (λ_p): Typically 468 nanometers (nm). This is the wavelength at which the spectral power distribution is at its maximum.
• Dominant Wavelength (λ_d): Ranges from 464.5 nm to 476.5 nm. This is the single wavelength perceived by the human eye that matches the color of the emitted light. A tolerance of ±1 nm is noted.
• Spectral Radiation Bandwidth (Δλ): Typically 35 nm. This is the full width at half maximum (FWHM) of the emission spectrum, describing the purity of the color.
• Forward Voltage (V_F): Typically 3.8 V, with a maximum of 4.5 V at I_F = 20 mA. This is the voltage drop across the LED when operating.
• Reverse Current (I_R): Maximum of 50 μA when a reverse voltage (V_R) of 5 V is applied.

3. Binning System Explanation

To ensure color and brightness consistency in production, LEDs are sorted into bins. This device uses two independent binning parameters.

3.1 Luminous Intensity Binning

The luminous output is categorized into four bins (N1, N2, P1, P2), each defining a specific millicandela (mcd) range measured at I_F = 20 mA. The bins ensure that LEDs within a specific order have similar brightness levels. The tolerance for luminous intensity is specified as ±11%.

• Bin N1: 28.5 - 36.0 mcd
• Bin N2: 36.0 - 45.0 mcd
• Bin P1: 45.0 - 57.0 mcd
• Bin P2: 57.0 - 72.0 mcd

3.2 Dominant Wavelength Binning

The color (dominant wavelength) is categorized into four bins (A9, A10, A11, A12), each covering a specific nanometer range. This ensures color uniformity. The tolerance for dominant wavelength is ±1 nm.

• Bin A9: 464.5 - 467.5 nm
• Bin A10: 467.5 - 470.5 nm
• Bin A11: 470.5 - 473.5 nm
• Bin A12: 473.5 - 476.5 nm

The product number likely incorporates codes (like \"AN1P2\") that specify which intensity and wavelength bins are included in a particular reel or order.

4. Performance Curve Analysis

While specific graphical curves are not detailed in the provided text, typical electro-optical characteristic curves for such an LED would include:

• Forward Current vs. Forward Voltage (I-V Curve): This non-linear curve shows the relationship between the current through the LED and the voltage across it. A small increase in voltage beyond the turn-on threshold leads to a large increase in current, highlighting the necessity for current-limiting circuitry.
• Luminous Intensity vs. Forward Current: This curve typically shows that light output increases with current but may become sub-linear at higher currents due to thermal and efficiency effects.
• Luminous Intensity vs. Ambient Temperature: The light output of LEDs generally decreases as the junction temperature increases. Understanding this derating is crucial for applications operating at high ambient temperatures.
• Spectral Distribution: A plot of relative intensity versus wavelength, showing the peak at ~468 nm and the ~35 nm FWHM bandwidth.

5. Mechanical and Package Information

5.1 Package Dimensions

The device has a rectangular footprint. Key dimensions (in millimeters, with a typical tolerance of ±0.1mm unless noted) include a body length of 2.2 mm, a body width of 2.1 mm, and a height of approximately 1.1 mm. The datasheet includes a detailed dimensional drawing showing pad layout, terminal sizes, and recommended PCB land pattern to ensure proper soldering and mechanical stability.

5.2 Polarity Identification

The cathode is typically marked, often by a notch, a dot, or a green marking on the package itself or the carrier tape. Correct polarity must be observed during placement to ensure the device functions.

6. Soldering and Assembly Guidelines

6.1 Current Limiting

Critical: An external current-limiting resistor or constant-current driver circuit must be used in series with the LED. The forward voltage has a negative temperature coefficient and a small variation. Without current limiting, a slight increase in supply voltage can cause a large, potentially destructive, increase in forward current.

6.2 Storage and Moisture Sensitivity

The components are packaged in a moisture-resistant barrier bag with desiccant to prevent moisture absorption, which can cause \"popcorning\" (package cracking) during reflow soldering.

• Do not open the bag until ready for use.
• After opening, store unused LEDs at ≤30°C and ≤60% Relative Humidity.
• The \"floor life\" after bag opening is 168 hours (7 days).
• If the floor life is exceeded or the desiccant indicator shows saturation, a bake-out at 60 ±5°C for 24 hours is required before soldering.

6.3 Reflow Soldering Profile

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

• Pre-heating: Ramp from ambient to 150-200°C over 60-120 seconds.
• Soak/Preflow: Maintain above 217°C for 60-150 seconds.
• Reflow: Peak temperature must not exceed 260°C, and the time above 255°C must not exceed 30 seconds. The time at the actual peak (260°C) must be 10 seconds maximum.
• Cooling: Maximum cooling rate of 6°C/second.

Important Restrictions: Reflow soldering should not be performed more than two times on the same device. Avoid mechanical stress on the LED during heating and do not warp the PCB after soldering.

6.4 Hand Soldering and Rework

If hand soldering is unavoidable, use a soldering iron with a tip temperature <350°C, apply heat to each terminal for ≤3 seconds, and use an iron with a power rating ≤25W. Allow a cooling interval of >2 seconds between terminals. Rework is strongly discouraged. If absolutely necessary, use a dual-head soldering iron to simultaneously heat both terminals for removal, and verify device functionality afterwards, as damage is likely.

7. Packaging and Ordering Information

7.1 Packaging Specification

The device is supplied in embossed carrier tape with a width of 8mm, wound on a standard 7-inch (178mm) diameter reel. Each reel contains 2000 pieces. The reel, tape, and cover tape dimensions are provided in the datasheet with tolerances of typically ±0.1mm.

7.2 Label Explanation

The packaging label contains several codes:

• CPN: Customer's Product Number (optional).
• P/N: Manufacturer's Product Number (e.g., 22-21/BHC-AN1P2/2C).
• QTY: Packing Quantity (e.g., 2000).
• CAT: Luminous Intensity Rank (Bin code for brightness).
• HUE: Chromaticity Coordinates & Dominant Wavelength Rank (Bin code for color).
• REF: Forward Voltage Rank.
• LOT No: Manufacturing Lot Number for traceability.

8. Application Suggestions

8.1 Typical Application Scenarios

• Backlighting: Illumination for instrument panel dashboards, membrane switches, and control panels.
• Telecommunication Equipment: Status indicators and keypad backlighting in telephones, fax machines, and networking devices.
• LCD Backlighting: Edge-lighting or direct backlighting for small monochrome or color LCD displays.
• General Indication: Power-on indicators, status lights, and decorative lighting in consumer electronics.

8.2 Design Considerations

• Thermal Management: While power dissipation is low, ensuring adequate PCB copper area or thermal vias under the LED pad can help maintain lower junction temperature, preserving luminous output and longevity.
• Current Drive: Always design for constant current drive or use a series resistor calculated based on the maximum forward voltage (V_F) to guarantee the current never exceeds the absolute maximum rating under worst-case conditions (e.g., low V_F device, high supply voltage).
• ESD Protection: Implement ESD protection on input lines if the LED is user-accessible, and follow ESD-safe handling during assembly.

9. Technical Comparison and Differentiation

The primary differentiation of the 22-21 package compared to larger SMD LEDs (e.g., 3528, 5050) or traditional through-hole LEDs is its ultra-miniature size, enabling design in space-constrained applications. Compared to other blue LEDs, its specific combination of typical wavelength (~468 nm), wide viewing angle (130°), and defined binning structure offers predictable color and brightness for consistent product appearance. Its compliance with halogen-free and RoHS standards makes it suitable for environmentally conscious designs required in global markets.

10. Frequently Asked Questions (Based on Technical Parameters)

Q: Why is a current-limiting resistor mandatory?
A: The LED's I-V characteristic is exponential. A small change in forward voltage causes a large change in current. Without a resistor, variations in supply voltage or the LED's own V_F could drive the current beyond the 20mA maximum, leading to rapid overheating and failure.

Q: Can I drive this LED with a 3.3V supply?
A: Possibly, but with caution. The typical V_F is 3.8V, which is higher than 3.3V. At 3.3V, the LED may not turn on, or will be very dim. You need a supply voltage higher than the maximum V_F (4.5V) plus the voltage drop across your current-limiting resistor. A boost converter or higher voltage supply (e.g., 5V) is typically used.

Q: What does the 130-degree viewing angle mean?
A> It means the angle at which the luminous intensity is half of the intensity measured directly on-axis (0 degrees). A 130-degree angle is considered \"wide viewing,\" meaning the light is spread out and visible from a broad side angle, suitable for indicator lights that need to be seen from different positions.

Q: How do I interpret the bin codes (e.g., AN1P2) in my order?
A> The bin codes specify the guaranteed ranges for luminous intensity and dominant wavelength for all LEDs in that batch. \"AN1\" likely refers to a specific dominant wavelength bin (e.g., A11), and \"P2\" refers to the luminous intensity bin (57.0-72.0 mcd). This ensures visual consistency across all units in your production run.

11. Practical Design and Usage Case

Scenario: Designing a backlit push-button switch. The switch has a small translucent icon. The designer selects this 22-21 blue LED for its compact size. A 5V supply rail is available on the PCB. To limit the current to 15 mA (a safe value below the 20mA max for longer life), a series resistor is calculated: R = (V_supply - V_F) / I_F. Using the maximum V_F of 4.5V ensures enough current even for a \"high V_F\" LED: R = (5V - 4.5V) / 0.015A ≈ 33.3 Ohms. A standard 33 Ohm resistor is chosen. The PCB land pattern is designed exactly per the datasheet's recommended footprint. During assembly, the moisture-sensitive devices are used within the 7-day floor life after the bag is opened, and the board undergoes a single reflow pass using the specified temperature profile.

12. Operating Principle Introduction

This LED operates on the principle of electroluminescence in a semiconductor p-n junction. The active region is composed of InGaN. When a forward voltage exceeding the diode's turn-on threshold is applied, electrons from the n-type region and holes from the p-type region are injected into the active region. When these charge carriers recombine, they release energy in the form of photons (light). The specific composition of the InGaN alloy determines the bandgap energy, which in turn dictates the wavelength (color) of the emitted light—in this case, blue. The water-clear epoxy resin encapsulant protects the semiconductor chip, acts as a lens to shape the light output (creating the 130° viewing angle), and provides mechanical stability.

13. Technology Trends

The development of efficient blue LEDs based on InGaN was a foundational achievement in solid-state lighting, enabling the creation of white LEDs (via phosphor conversion) and full-color displays. The trend for components like the 22-21 continues towards further miniaturization, increased efficiency (higher luminous intensity per mA), and tighter binning tolerances for superior color and brightness uniformity. Integration with onboard control circuitry (like integrated driver ICs in LED packages) is also a growing trend, though for simple indicator LEDs, the discrete, cost-effective approach represented by this component remains highly relevant for a vast array of applications.