SMD Middle Power Red LED 67-21S Datasheet - PLCC-2 Package - 1.9-2.6V - 70mA - 182mW - English Technical Document

1. Product Overview

The 67-21S is a surface-mount middle power LED designed for general lighting applications. It utilizes a PLCC-2 (Plastic Leaded Chip Carrier) package, offering a compact form factor suitable for automated assembly processes. The primary emitted color is red, achieved through an AlGaInP (Aluminum Gallium Indium Phosphide) chip material encapsulated in water-clear resin. This combination provides a wide viewing angle of 120 degrees, making it suitable for applications requiring broad light distribution.

Key advantages of this LED include its high efficacy, which translates to good luminous output for its power consumption level, and its compliance with environmental standards such as being lead-free (Pb-free) and RoHS compliant. The package is engineered for reliability in various operating conditions.

2. Technical Specifications and In-Depth Analysis

2.1 Absolute Maximum Ratings

The device's operational limits are defined under specific conditions (soldering point temperature at 25°C). The maximum continuous forward current (I_F) is 70 mA. For pulsed operation, a peak forward current (I_FP) of 140 mA is permissible under a duty cycle of 1/10 and a pulse width of 10 ms. The maximum power dissipation (P_d) is 182 mW. The operating temperature range (T_opr) is from -40°C to +85°C, while the storage temperature (T_stg) extends from -40°C to +100°C. The thermal resistance from the junction to the soldering point (R_{th J-S}) is 50 °C/W, which is a critical parameter for thermal management design. The maximum allowable junction temperature (T_j) is 115°C. Soldering must adhere to strict profiles: reflow soldering at 260°C for a maximum of 10 seconds or hand soldering at 350°C for a maximum of 3 seconds. The component is sensitive to electrostatic discharge (ESD), necessitating proper handling procedures.

2.2 Electro-Optical Characteristics

Measured at a soldering point temperature of 25°C and a forward current of 60 mA, the device exhibits a luminous flux (Φ) ranging from a minimum of 9.0 lm to a maximum of 13.0 lm, with a typical tolerance of ±11%. The forward voltage (V_F) ranges from 1.9 V to 2.6 V at the same test current, with a typical tolerance of ±0.1V. The viewing angle (2θ_1/2) is typically 120 degrees. The reverse current (I_R) is specified at a maximum of 50 µA when a reverse voltage (V_R) of 5V is applied. These parameters define the core performance under standard operating conditions.

3. Binning System Explanation

The product is classified into bins to ensure consistency in key parameters. This allows designers to select LEDs that match their specific application requirements for brightness and electrical characteristics.

3.1 Luminous Flux Binning

Luminous flux is categorized into several bin codes (B8, B9, L1, L2, L3) with defined minimum and maximum values measured at I_F=60mA. For example, bin B8 covers 9.0 to 9.5 lm, while bin L3 covers 12.0 to 13.0 lm. The overall tolerance remains ±11%.

3.2 Forward Voltage Binning

Forward voltage is binned using codes from 26 to 32, each representing a 0.1V range starting from 1.9-2.0V (code 26) up to 2.5-2.6V (code 32). The tolerance is ±0.1V.

3.3 Dominant Wavelength Binning

The dominant wavelength, which defines the perceived color of the red light, is binned into two codes: R51 (620-625 nm) and R52 (625-630 nm). The measurement tolerance is ±1 nm.

4. Performance Curve Analysis

The datasheet provides several characteristic graphs that illustrate device behavior under varying conditions.

4.1 Spectrum Distribution

A graph shows the relative luminous intensity versus wavelength, typically peaking within the red spectrum (around 620-640 nm for this device), confirming the dominant wavelength bins.

4.2 Forward Voltage vs. Junction Temperature

Figure 1 shows the forward voltage shift relative to junction temperature. The forward voltage typically decreases as the junction temperature increases, which is a common characteristic of semiconductor diodes.

4.3 Relative Radiometric Power vs. Forward Current

Figure 2 depicts how the light output (relative radiometric power) increases with forward current. The relationship is generally linear at lower currents but may exhibit saturation effects at higher currents.

4.4 Relative Luminous Flux vs. Junction Temperature

Figure 3 illustrates the dependence of light output on junction temperature. Luminous flux typically decreases as the junction temperature rises, highlighting the importance of effective thermal management to maintain consistent brightness.

4.5 Forward Current vs. Forward Voltage (IV Curve)

Figure 4 is the fundamental current-voltage (IV) characteristic curve at an ambient temperature of 25°C. It shows the exponential relationship typical of a diode.

4.6 Maximum Driving Current vs. Soldering Temperature

Figure 5 provides a derating curve, showing the maximum allowable forward current as a function of the soldering point temperature, considering the thermal resistance (R_{th j-s} = 50 °C/W). This is crucial for determining safe operating currents at elevated ambient temperatures.

4.7 Radiation Pattern

Figure 6 is a polar diagram showing the spatial distribution of light intensity (radiation pattern). The wide, Lambertian-like pattern confirms the 120-degree viewing angle.

5. Mechanical and Package Information

5.1 Package Dimensions

A detailed dimensional drawing of the PLCC-2 package is provided. Key dimensions include the overall length, width, and height, as well as the lead (pad) spacing and size. The drawing includes a top view indicating the cathode marking. Unless otherwise specified, the dimensional tolerance is ±0.15 mm.

6. Soldering and Assembly Guidelines

The datasheet specifies two soldering methods. For reflow soldering, the maximum peak temperature should not exceed 260°C, and the time above 260°C should be limited to 10 seconds. For hand soldering, the iron tip temperature should not exceed 350°C, and contact time should be limited to 3 seconds per lead. These limits are essential to prevent damage to the plastic package and the internal wire bonds. The device is sensitive to moisture; therefore, if the packaging has been opened, baking may be required before soldering if the exposure time exceeds the specified level (not detailed in this excerpt).

7. Packaging and Ordering Information

7.1 Moisture Resistant Packing

The LEDs are supplied in moisture-resistant packaging. They are typically loaded into carrier tapes, which are then wound onto reels. A common configuration is 4000 pieces per reel. The packaging includes a desiccant and is sealed within an aluminum moisture-proof bag with appropriate labels.

7.2 Label Explanation

The reel label contains several key fields: CPN (Customer's Product Number), P/N (Product Number), QTY (Packing Quantity), CAT (Luminous Intensity Rank, corresponding to flux bin), HUE (Dominant Wavelength Rank), REF (Forward Voltage Rank), and LOT No (Lot Number for traceability).

7.3 Reel and Tape Dimensions

Detailed drawings specify the dimensions of the reel (diameter, width, hub size) and the carrier tape (pocket dimensions, pitch, tape width). Tolerances are typically ±0.1 mm unless stated otherwise.

8. Application Suggestions

The datasheet lists primary application areas: Decorative and Entertainment Lighting, Agriculture Lighting, and General Use. The wide viewing angle and good efficacy make it suitable for ambient lighting, signage, horticultural lighting for specific plant growth stages, and decorative fixtures where red accent lighting is desired. When designing a driver circuit, the forward voltage bin and maximum current ratings must be considered. An external current-limiting resistor or constant-current driver is mandatory to prevent over-current damage, as stated in the precautions.

9. Reliability Testing

A comprehensive reliability test plan is outlined, demonstrating product robustness. Tests are conducted with a 90% confidence level and an LTPD (Lot Tolerance Percent Defective) of 10%. The test items include: Reflow Soldering (260°C/10s), Thermal Shock (-10°C to +100°C), Temperature Cycle (-40°C to +100°C), High Temperature/Humidity Storage (85°C/85% RH), High Temperature/Humidity Operation (85°C/85% RH, 35mA), Low/High Temperature Storage, and various High/Low Temperature Operation Life tests under different current and temperature conditions. Sample size for each test is 22 pieces with an accept/reject criterion of 0/1.

10. Precautions for Use

The most critical precaution is protection against over-current. The LED must be driven with a series resistor or a proper constant-current circuit. Exceeding the absolute maximum ratings for current, voltage, power, or temperature will likely cause permanent damage. Proper ESD handling practices must be followed during assembly. The thermal resistance value must be used to calculate the junction temperature under expected operating conditions to ensure it remains below 115°C.

11. Technical Comparison and Differentiation

As a middle power LED in a PLCC-2 package, this device sits between low-power indicator LEDs and high-power illumination LEDs. Its key differentiators are its balance of good luminous output (up to 13 lm) with a relatively modest power consumption (max 182 mW) and the standardized PLCC-2 footprint which simplifies PCB design and sourcing. The detailed binning system offers predictability for volume production.

12. Frequently Asked Questions (Based on Technical Parameters)

Q: What driver current should I use?
A: The device is characterized at 60mA. You can operate it up to the maximum continuous current of 70mA, but you must ensure the junction temperature does not exceed 115°C by considering ambient temperature, thermal design, and using the derating curve (Fig. 5).
Q: How do I identify the cathode?
A: The package has a visual marker (typically a notch or a green dot) on the top side near the cathode lead. Refer to the package dimension drawing.
Q: Can I use it for pulsed operation?
A: Yes, but the peak current must not exceed 140mA under a 1/10 duty cycle and 10ms pulse width. The average current must still respect the continuous rating.
Q: Why is the luminous flux given as a range?
A: Due to manufacturing variations, LEDs are binned. You select a bin (e.g., L2 for 11-12 lm) to guarantee a minimum performance level for your design.

13. Design and Usage Case Study

Consider designing a decorative LED strip for ambient red lighting. The designer selects the 67-21S LED in bin L2 (11-12 lm) and voltage bin 28 (2.1-2.2V) for consistency. The strip operates at 12V DC. To drive each LED at 60mA, a series resistor value is calculated: R = (V_supply - V_F) / I_F. Using the maximum V_F of 2.2V for safety, R = (12V - 2.2V) / 0.060A ≈ 163 ohms. A standard 160-ohm resistor would be chosen. Multiple such LED+resistor pairs are connected in parallel across the 12V rail. The PCB layout ensures adequate copper area for heat dissipation from the LED solder pads, considering the thermal resistance to ambient.

14. Operating Principle

This LED operates on the principle of electroluminescence in a semiconductor p-n junction. When a forward voltage exceeding the diode's threshold (around 1.9-2.6V for this AlGaInP material) is applied, electrons and holes are injected across the junction. Their recombination releases energy in the form of photons (light). The specific composition of the AlGaInP semiconductor alloy determines the bandgap energy, which defines the wavelength (color) of the emitted light, in this case, red. The water-clear resin encapsulation protects the chip and aids in light extraction.

15. Industry Trends

The middle-power LED segment continues to evolve towards higher efficacy (more lumens per watt), improved color consistency, and lower cost. There is a trend for more sophisticated binning and tighter tolerances to meet the demands of applications requiring uniform appearance, such as video walls and linear lighting. Packaging technology is also advancing to offer better thermal performance from the same footprint, allowing for higher drive currents or longer lifespan. The move towards standardized footprints like PLCC-2 facilitates design reuse and supply chain flexibility.