SMD LED 12-21/BHC-ZL1M2RY/2C Datasheet - Size 2.0x1.25x0.8mm - Voltage 2.5-3.1V - Blue Color - English Technical Document

1. Product Overview

The 12-21/BHC-ZL1M2RY/2C is a surface-mount device (SMD) light-emitting diode (LED) designed for modern, compact electronic applications. This component represents a significant advancement over traditional lead-frame type LEDs, offering substantial benefits in terms of board space utilization and design flexibility.

1.1 Core Advantages and Product Positioning

The primary advantage of this LED is its miniature footprint. The 12-21 package is significantly smaller than conventional through-hole components. This reduction in size enables designers to achieve higher component packing density on printed circuit boards (PCBs), ultimately leading to smaller overall equipment size. The lightweight nature of the SMD package further makes it ideal for portable and miniature applications where weight is a critical factor.

This LED is a mono-color type, emitting blue light, and is constructed using lead-free (Pb-free) materials. It complies with major international environmental and safety regulations, including the EU's RoHS (Restriction of Hazardous Substances) directive, REACH regulation, and is classified as halogen-free, with bromine (Br) and chlorine (Cl) content kept below specified limits.

1.2 Target Market and Applications

This component is targeted at a broad range of consumer, industrial, and communication electronics. Its key application areas include:

• Backlighting: Ideal for illuminating dashboards, switches, and keypads.
• Telecommunication Equipment: Serves as status indicators and backlighting for devices such as telephones and fax machines.
• Display Technology: Suitable for flat backlighting units behind liquid crystal displays (LCDs) and for illuminating symbols.
• General Purpose Indication: Can be used in a wide variety of electronic devices requiring a compact, reliable visual indicator.

The product is supplied in industry-standard 8mm tape on 7-inch diameter reels, making it fully compatible with high-speed automated pick-and-place assembly equipment. It is also designed to withstand standard infrared and vapor phase reflow soldering processes.

2. In-Depth Technical Parameter Analysis

A thorough understanding of the electrical and optical specifications is crucial for reliable circuit design and optimal performance.

2.1 Absolute Maximum Ratings

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

• Reverse Voltage (V_R): 5V. Exceeding this voltage in reverse bias can cause immediate junction breakdown.
• Continuous Forward Current (I_F): 10 mA. This is the maximum DC current that can be applied continuously.
• Peak Forward Current (I_FP): 100 mA. This pulsed current rating (at 1/10 duty cycle, 1kHz) is useful for brief, high-intensity flashing applications but must not be used for continuous operation.
• Power Dissipation (P_d): 40 mW. This limit, combined with the forward voltage, dictates the maximum allowable continuous current under specific thermal conditions.
• Electrostatic Discharge (ESD) Human Body Model (HBM): 150V. This is a relatively low ESD tolerance, indicating the device is sensitive to static electricity. Proper ESD handling procedures are mandatory during assembly and handling.
• Operating Temperature (T_opr): -40°C to +85°C. The device is rated for industrial temperature ranges.
• Storage Temperature (T_stg): -40°C to +90°C.
• Soldering Temperature: The device can withstand reflow soldering with a peak temperature of 260°C for up to 10 seconds. For hand soldering, the iron tip temperature must not exceed 350°C, and contact time per lead should be limited to 3 seconds.

2.2 Electro-Optical Characteristics

These parameters are measured at a standard test condition of 25°C ambient temperature and a forward current (I_F) of 5 mA, unless otherwise specified.

• Luminous Intensity (I_v): Ranges from a minimum of 11.5 mcd to a maximum of 28.5 mcd. The typical value is not specified, indicating performance is managed through a binning system (detailed later).
• Viewing Angle (2θ_1/2): 120 degrees. This wide viewing angle makes the LED suitable for applications requiring broad illumination or visibility from multiple angles.
• Peak Wavelength (λ_p): Typically 468 nm, placing it in the blue region of the visible spectrum.
• Dominant Wavelength (λ_d): Specified between 465 nm and 475 nm. This is the wavelength perceived by the human eye and is also managed through binning.
• Spectral Bandwidth (Δλ): Typically 25 nm, indicating the spread of the emitted light around the peak wavelength.
• Forward Voltage (V_F): Ranges from 2.5V to 3.1V at 5 mA. This parameter is critical for designing the current-limiting resistor in series with the LED. The voltage binning system helps designers select LEDs with consistent voltage drops.
• Reverse Current (I_R): Maximum of 50 μA when a 5V reverse bias is applied. Important Note: The datasheet explicitly states that reverse voltage condition is for test purposes only, and the device must not be operated in reverse bias in an actual circuit.

3. Binning System Explanation

To ensure consistency in mass production, LEDs are sorted into performance bins. This allows designers to select components that meet specific minimum criteria for their application.

3.1 Luminous Intensity Binning

LEDs are categorized into four intensity bins (L1, L2, M1, M2) based on their measured output at 5 mA.

• L1: 11.5 – 14.5 mcd
• L2: 14.5 – 18.0 mcd
• M1: 18.0 – 22.5 mcd
• M2: 22.5 – 28.5 mcd

A tolerance of ±11% is applied to the luminous intensity.

3.2 Dominant Wavelength Binning

The color (hue) of the blue light is controlled through wavelength binning. Two bins are defined:

• Bin X: 465 – 470 nm
• Bin Y: 470 – 475 nm

A tighter tolerance of ±1 nm is specified for the dominant wavelength.

3.3 Forward Voltage Binning

To aid in power supply design and ensure uniform brightness in parallel strings, LEDs are binned by forward voltage at 5 mA.

• Bin 9: 2.5 – 2.7 V
• Bin 10: 2.7 – 2.9 V
• Bin 11: 2.9 – 3.1 V

The tolerance for forward voltage is ±0.1V.

4. Mechanical and Packaging Information

4.1 Package Dimensions

The 12-21 SMD LED has a compact rectangular package. Key dimensions (in millimeters) include a typical body length of 2.0 mm, a width of 1.25 mm, and a height of 0.8 mm. The datasheet provides a detailed dimensional drawing showing the lead spacing, pad sizes, and overall tolerances, which are typically ±0.1 mm unless otherwise noted. This drawing is essential for creating the correct PCB footprint to ensure proper soldering and alignment.

4.2 Polarity Identification

The component features a polarity marker, typically a notch or a dot on the package, to identify the cathode. Correct orientation during placement is critical for circuit functionality.

4.3 Tape and Reel Packaging

The LEDs are supplied in moisture-resistant packaging. They are loaded into carrier tape with pockets sized to hold the 12-21 package. The standard reel contains 2000 pieces. Reel dimensions (such as hub diameter, reel width, and flange diameter) are provided to ensure compatibility with automated assembly machinery. The packaging includes a desiccant and is sealed within an aluminum moisture-proof bag to protect the devices from ambient humidity during storage and transport.

4.4 Label Explanation

The packaging labels contain critical information for traceability and identification:

• P/N: Product Number (e.g., 12-21/BHC-ZL1M2RY/2C).
• QTY: Packing Quantity per reel.
• CAT: Luminous Intensity Rank (corresponds to the L1, M2, etc., bin code).
• HUE: Chromaticity Coordinates & Dominant Wavelength Rank (corresponds to the X, Y bin code).
• REF: Forward Voltage Rank (corresponds to the 9, 10, 11 bin code).
• LOT No: Manufacturing Lot Number for quality control.

5. Soldering and Assembly Guidelines

Proper handling and soldering are vital for reliability. The LED is sensitive to thermal and mechanical stress.

5.1 Storage and Moisture Sensitivity

The product is moisture-sensitive. Key precautions include:

• Do not open the moisture-proof bag until the components are ready for use.
• After opening, unused LEDs should be stored at ≤30°C and ≤60% relative humidity.
• The "floor life" after opening the bag is 168 hours (7 days). If not used within this time, components must be re-baked at 60±5°C for 24 hours and re-bagged with desiccant.

5.2 Reflow Soldering Profile

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

• Pre-heating: 150–200°C for 60–120 seconds.
• Time Above Liquidus (TAL): 60–150 seconds above 217°C.
• Peak Temperature: Maximum of 260°C, held for no more than 10 seconds.
• Heating/Cooling Rates: Maximum heating rate of 6°C/sec to 255°C, and maximum cooling rate of 3°C/sec.
• Reflow soldering should not be performed more than two times on the same component.

5.3 Hand Soldering Precautions

If hand soldering is necessary, extreme care is required:

• Use a soldering iron with a tip temperature ≤350°C.
• Limit contact time per terminal to ≤3 seconds.
• Use a low-power iron (≤25W).
• Allow a cooling interval of at least 2 seconds between soldering each terminal.
• Avoid applying mechanical stress to the LED body during heating.

5.4 Circuit Design Protection

Over-current Protection: An external current-limiting resistor is absolutely mandatory. The forward voltage has a negative temperature coefficient, meaning as the LED heats up, V_F drops, which can lead to a rapid, uncontrolled increase in current if driven by a voltage source without a series resistor. This will result in thermal runaway and device failure.

6. Application Design Considerations and Restrictions

6.1 Design Considerations

• Current Driving: Always drive the LED with a constant current or use a voltage source with a series resistor calculated based on the worst-case V_F (minimum) from the binning range to ensure the current never exceeds the absolute maximum rating.
• Thermal Management: While the package is small, ensuring adequate PCB copper area around the thermal pads can help dissipate heat, especially when operating near the maximum current or at high ambient temperatures.
• ESD Protection: Implement ESD protection on input lines if the LED is connected to user-accessible ports, given its low 150V HBM rating.

6.2 Application Restrictions

The datasheet includes a critical disclaimer regarding high-reliability applications. This product, as specified, may not be suitable for applications where failure could lead to serious injury, loss of life, or significant property damage. This explicitly includes:

• Military and aerospace systems
• Automotive safety and security systems (e.g., airbags, braking systems)
• Medical life-support equipment

For such applications, components with different qualifications, testing, and reliability guarantees are required. Engineers must consult with the manufacturer for products designed for these critical use cases.

7. Technical Comparison and Differentiation

The 12-21/BHC-ZL1M2RY/2C differentiates itself primarily through its package size and performance consistency via binning.

• vs. Larger SMD Packages (e.g., 3528, 5050): It offers a much smaller footprint, enabling higher-density designs but typically at a lower total light output per device.
• vs. Through-Hole LEDs: It eliminates the need for drilling holes in the PCB, simplifies automated assembly, reduces weight, and allows for smaller product form factors.
• vs. Non-Binned LEDs: The comprehensive binning system for intensity, wavelength, and voltage provides designers with predictable performance, which is crucial for applications requiring color or brightness uniformity across multiple LEDs.

8. Frequently Asked Questions (FAQ)

Q: What resistor value should I use to drive this LED at 5 mA from a 5V supply?

A: Using Ohm's Law: R = (V_supply - V_F) / I_F. For worst-case design (ensuring current never exceeds 5 mA even with the lowest V_F), use the minimum V_F from Bin 9 (2.5V). R = (5V - 2.5V) / 0.005A = 500 Ω. A standard 510 Ω resistor would be a safe choice, resulting in a current slightly below 5 mA.

Q: Can I pulse this LED at 50 mA?

A: Yes, but only under specific conditions. The datasheet allows a Peak Forward Current (I_FP) of 100 mA at a 1/10 duty cycle and 1 kHz frequency. Pulsing at 50 mA with a similar or lower duty cycle would generally be acceptable, but you must verify the average current and power dissipation do not exceed the continuous ratings.

Q: Why is the storage time after opening the bag limited to 7 days?

A> SMD LEDs can absorb moisture from the air. During the high-temperature reflow soldering process, this trapped moisture can rapidly expand, causing internal delamination or "popcorning," which cracks the package and destroys the device. The 7-day limit is based on the moisture sensitivity level (MSL) of the component.

Q: The viewing angle is 120 degrees. How is this measured?

A> The viewing angle (2θ_1/2) is the full angle at which the luminous intensity drops to half of its maximum value (measured at 0 degrees, directly on-axis). A 120-degree angle means the LED emits light effectively over a very wide cone.

9. Operating Principle and Technology

This LED is based on InGaN (Indium Gallium Nitride) semiconductor technology. When a forward voltage exceeding the diode's turn-on threshold (approximately 2.5-3.1V) is applied, electrons and holes are injected into the active region of the semiconductor junction. Their recombination releases energy in the form of photons (light). The specific composition of the InGaN alloy determines the bandgap energy, which directly corresponds to the wavelength (color) of the emitted light—in this case, blue (~468 nm). The "water clear" resin lens is used to maximize light extraction from the semiconductor chip.

10. Industry Trends and Context

The 12-21 package is part of a long-term industry trend towards miniaturization of electronic components. The drive for smaller, lighter, and more power-efficient devices in consumer electronics, wearables, and IoT sensors continues to push the development of ever-smaller LED packages. Furthermore, the emphasis on environmental compliance (RoHS, halogen-free) and supply chain management through detailed binning and traceability (lot numbers) reflects broader industry standards for quality and sustainability. The move to Pb-free soldering, for which this component is qualified, is now a global norm in electronics manufacturing.