SMD LED 17-21 Brilliant Yellow Datasheet - Package 1.6x0.8x0.6mm - Voltage 1.75-2.35V - Power 60mW - English Technical Documentation

1. Product Overview

The 17-21 SMD LED is a compact, surface-mount device designed for high-density applications requiring a brilliant yellow light source. Its primary advantage lies in its significantly reduced footprint compared to traditional lead-frame LEDs, enabling smaller printed circuit board (PCB) designs, higher component packing density, and ultimately more compact end-user equipment. The lightweight construction further makes it ideal for miniature and portable applications where weight and space are critical constraints.

This LED is a mono-color type, emitting a brilliant yellow light. It is constructed using AlGaInP (Aluminum Gallium Indium Phosphide) semiconductor material, which is known for its high efficiency and color purity in the yellow to red spectrum. The device is encapsulated in a water-clear resin, allowing for maximum light output. It is fully compliant with RoHS (Restriction of Hazardous Substances), EU REACH regulations, and is halogen-free, meeting stringent environmental standards (Br <900 ppm, Cl <900 ppm, Br+Cl < 1500 ppm). The product is supplied in 8mm tape on 7-inch diameter reels, making it fully compatible with automated pick-and-place assembly equipment and standard infrared or vapor phase reflow soldering processes.

2. Technical Parameter Deep Dive

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 and should be avoided for reliable performance.

• Reverse Voltage (VR): 5 V. Exceeding this voltage in reverse bias can cause junction breakdown.
• Continuous Forward Current (IF): 25 mA. The maximum DC current that can be continuously applied.
• Peak Forward Current (IFP): 60 mA. This is the maximum pulsed forward current, permissible only under a duty cycle of 1/10 at 1 kHz. This rating is useful for multiplexing or brief over-current conditions.
• Power Dissipation (Pd): 60 mW. The maximum power the package can dissipate, calculated as Forward Voltage (VF) multiplied by Forward Current (IF).
• Electrostatic Discharge (ESD) Human Body Model (HBM): 2000 V. This indicates the device's sensitivity to static electricity. Proper ESD handling procedures are mandatory.
• Operating Temperature (Topr): -40 to +85 °C. The ambient temperature range over which the device is specified to operate.
• Storage Temperature (Tstg): -40 to +90 °C.
• Soldering Temperature (Tsol): For reflow soldering, a peak temperature of 260°C for a maximum of 10 seconds is specified. For hand soldering, the iron tip temperature should not exceed 350°C for a maximum of 3 seconds per terminal.

2.2 Electro-Optical Characteristics

These parameters are measured at a junction temperature (Tj) of 25°C and a forward current of 20 mA, which is the standard test condition.

• Luminous Intensity (Iv): Ranges from a minimum of 57.00 mcd to a maximum of 112.00 mcd. The typical value falls within this range. A tolerance of ±11% applies to the luminous intensity.
• Viewing Angle (2θ1/2): The typical full viewing angle at half intensity is 140 degrees, providing a wide emission pattern suitable for backlighting and indicator applications.
• Peak Wavelength (λp): The wavelength at which the spectral power distribution is maximum. The typical value is 591 nm, placing it in the brilliant yellow region.
• Dominant Wavelength (λd): Ranges from 585.50 nm to 591.50 nm. This is the single wavelength perceived by the human eye that matches the color of the LED's output. A tight tolerance of ±1 nm is specified.
• Spectral Bandwidth (Δλ): The typical full width at half maximum (FWHM) of the emission spectrum is 15 nm, indicating a relatively narrow and pure color emission.
• Forward Voltage (VF): Ranges from 1.75 V to 2.35 V at 20 mA. A tolerance of ±0.1 V is specified. This parameter is critical for designing the current-limiting circuitry.
• Reverse Current (IR): Maximum of 10 µA when a reverse voltage of 5V is applied. It is crucial to note that this device is not designed for operation in reverse bias; this test condition is for characterization only.

3. Binning System Explanation

To ensure consistency in production, LEDs are sorted into bins based on key performance parameters. This allows designers to select parts that meet specific requirements for brightness, color, and electrical characteristics.

3.1 Luminous Intensity Binning

Binned at IF=20mA. Three bins are defined: P2 (57.00-72.00 mcd), Q1 (72.00-90.00 mcd), and Q2 (90.00-112.00 mcd). This allows selection based on required brightness levels.

3.2 Dominant Wavelength Binning

Binned at IF=20mA. Two bins are defined: D3 (585.50-588.50 nm) and D4 (588.50-591.50 nm). This tight control ensures minimal color variation within an application.

3.3 Forward Voltage Binning

Binned at IF=20mA. Three bins are defined: 0 (1.75-1.95 V), 1 (1.95-2.15 V), and 2 (2.15-2.35 V). Selecting LEDs from the same voltage bin can help achieve more uniform brightness when driven by a constant voltage source or simplify current-limiting resistor calculations.

4. Performance Curve Analysis

While specific graphical curves are not detailed in the provided text, typical electro-optical characteristics for such LEDs would include several key relationships. The Current vs. Voltage (I-V) curve would show the exponential relationship, with the forward voltage increasing with current and temperature. The Luminous Intensity vs. Forward Current (I-L) curve would typically be nearly linear within the operating range, showing that light output is directly proportional to current. The Luminous Intensity vs. Ambient Temperature curve would show a decrease in output as temperature rises, a characteristic of all LEDs. The Spectral Distribution plot would show a single peak around 591 nm with a FWHM of approximately 15 nm, confirming the narrowband yellow emission. Understanding these curves is essential for thermal management and driving circuit design to maintain consistent performance over the operating temperature range.

5. Mechanical and Package Information

5.1 Package Dimensions

The 17-21 SMD LED has a compact surface-mount package. Key dimensions (with a standard tolerance of ±0.1 mm unless otherwise noted) include a length of 1.6 mm, a width of 0.8 mm, and a height of 0.6 mm. The package features a cathode mark for correct polarity identification during assembly. Precise land pattern (footprint) recommendations should be derived from the detailed dimensioned drawing to ensure proper soldering and alignment.

5.2 Polarity Identification

Correct polarity is essential for device operation. The package includes a distinct cathode mark. Placing the LED in reverse polarity will prevent it from illuminating and, if the reverse voltage exceeds the absolute maximum rating of 5V, may cause permanent damage.

6. Soldering and Assembly Guidelines

6.1 Reflow Soldering Profile

The device is compatible with lead-free (Pb-free) reflow soldering processes. The recommended temperature profile includes: a pre-heating stage between 150-200°C for 60-120 seconds; a time above liquidus (217°C) of 60-150 seconds; a peak temperature not exceeding 260°C, held for a maximum of 10 seconds; and maximum ramp-up and cool-down rates of 6°C/sec and 3°C/sec respectively. Reflow soldering should not be performed more than two times. Stress on the LED body during heating and warping of the PCB after soldering must be avoided.

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. A low-power iron (\u003c25W) is recommended. Allow an interval of at least 2 seconds between soldering each terminal. Hand soldering poses a higher risk of thermal damage.

6.3 Storage and Moisture Sensitivity

The LEDs are packaged in moisture-resistant barrier bags with desiccant. The bag must not be opened until the components are ready for use. After opening, unused LEDs should be stored at 30°C or less and 60% relative humidity or less. The \"floor life\" after opening is 168 hours (7 days). If this time is exceeded or if the desiccant indicator shows saturation, the components must be baked at 60 ± 5°C for 24 hours before use to remove absorbed moisture and prevent \"popcorning\" during reflow.

7. Packaging and Ordering Information

The standard packaging consists of 3000 pieces per reel. The carrier tape and reel dimensions are specified to ensure compatibility with automated assembly equipment. The packaging label contains critical information for traceability and correct application: Customer Product Number (CPN), Product Number (P/N), Packing Quantity (QTY), Luminous Intensity Rank (CAT), Chromaticity/Dominant Wavelength Rank (HUE), Forward Voltage Rank (REF), and Lot Number (LOT No).

8. Application Recommendations

8.1 Typical Application Scenarios

• Backlighting: Ideal for dashboard indicators, switch backlighting, and flat backlighting for LCDs and symbols due to its wide viewing angle and uniform light output.
• Telecommunication Equipment: Suitable as status indicators and keypad backlights in telephones and fax machines.
• General Indication: Can be used in a wide variety of consumer electronics, industrial controls, and appliances where a bright yellow indicator is required.

8.2 Design Considerations

Current Limiting: An external current-limiting resistor is absolutely mandatory. LEDs are current-driven devices, and a small change in forward voltage can cause a large change in current, potentially leading to thermal runaway and failure. The resistor value (R) can be calculated using Ohm's Law: R = (Vsupply - VF) / IF, where VF is the forward voltage of the LED at the desired current IF. Always design for the maximum specified VF to ensure the current does not exceed the limit. Thermal Management: While the power dissipation is low, maintaining a low junction temperature is key to long-term reliability and stable light output. Ensure adequate PCB copper area or thermal vias if operating at high ambient temperatures or near maximum current. ESD Protection: Implement appropriate ESD protection measures in the circuit and during handling, as the device is rated for 2000V HBM.

9. Technical Comparison and Differentiation

The primary differentiation of the 17-21 LED lies in its combination of a very small form factor (1.6x0.8mm) with the performance characteristics of AlGaInP technology. Compared to older through-hole yellow LEDs, it offers a massive reduction in board space and weight. Compared to other SMD yellow LEDs, its specific binning structure for luminous intensity (P2, Q1, Q2), dominant wavelength (D3, D4), and forward voltage (0, 1, 2) provides designers with a high degree of control over the consistency of their end product's visual and electrical performance. The wide 140-degree viewing angle is a key advantage for backlighting applications over narrower-angle devices.

10. Frequently Asked Questions (FAQs)

Q: What is the primary cause of LED failure in application?
A: The most common cause is over-current due to inadequate or missing current-limiting circuitry or driving the LED from an unregulated voltage source. Thermal overstress from excessive soldering heat or high ambient temperature operation is another major factor.

Q: Can I drive this LED directly from a 3.3V or 5V logic supply?
A: No. You must always use a series current-limiting resistor. For example, with a 5V supply and a typical VF of 2.0V at 20mA, the required resistor would be (5V - 2.0V) / 0.02A = 150 Ohms. Always calculate for the maximum VF to ensure safe current.

Q: Why is the storage and baking information so important?
A: SMD packages can absorb moisture from the air. During the high-temperature reflow soldering process, this trapped moisture can vaporize rapidly, creating internal pressure that can crack the epoxy resin package (\"popcorning\"), leading to immediate or latent failure.

Q: How do I interpret the bin codes on the label?
A: The CAT code corresponds to the luminous intensity bin (e.g., Q1), the HUE code to the dominant wavelength bin (e.g., D4), and the REF code to the forward voltage bin (e.g., 1). Selecting parts from the same bin codes ensures minimal variation within a production batch.

11. Practical Design and Usage Case

Case: Designing a status indicator panel with uniform brightness. A designer is creating a control panel with 20 yellow LED indicators. To ensure all LEDs appear equally bright, they specify LEDs from the same luminous intensity bin (e.g., all from Q1 bin: 72-90 mcd). To simplify the driver circuit design and ensure consistent current, they also specify LEDs from the same forward voltage bin (e.g., all from bin 1: 1.95-2.15V). They calculate a single current-limiting resistor value using the maximum VF from that bin (2.15V) to guarantee no LED exceeds 20mA even with supply voltage tolerances. The wide 140-degree viewing angle ensures the indicators are visible from various operator positions. The small 17-21 package allows them to place the indicators very close together on a dense PCB.

12. Operating Principle Introduction

Light Emitting Diodes (LEDs) are semiconductor devices that emit light through electroluminescence. When a forward voltage is applied across the p-n junction, electrons from the n-type material recombine with holes from the p-type material in the active region. For this specific brilliant yellow LED, the semiconductor material is AlGaInP. The energy bandgap of this compound semiconductor determines the wavelength (color) of the emitted photons. In this case, the bandgap is engineered to produce photons with a wavelength centered around 591 nm, which the human eye perceives as brilliant yellow. The water-clear epoxy resin encapsulant protects the semiconductor chip and acts as a lens, shaping the light output into the specified 140-degree viewing angle.

13. Technology Trends

The trend in indicator and backlight LEDs continues towards higher efficiency (more light output per unit of electrical power), smaller package sizes to enable ever-more compact devices, and improved color consistency and stability over temperature and lifetime. There is also a strong drive towards broader adoption of environmentally friendly materials and manufacturing processes, as evidenced by this product's RoHS, REACH, and halogen-free compliance. Integration, such as incorporating the current-limiting resistor or protection diodes within the LED package itself, is another ongoing trend to simplify circuit design and save board space. For yellow LEDs, AlGaInP remains the dominant high-performance material technology, with ongoing refinements to its epitaxial growth processes to yield better efficiency and tighter wavelength control.