SMD LED 18-225/B6R6C-C01/3T Datasheet - Size 1.6x0.8x0.7mm - Voltage 2.0-3.3V - Power 60-150mW - Blue & Red - English Technical Document

1. Product Overview

The 18-225 series represents a compact, surface-mount LED solution designed for modern electronic applications requiring miniaturization and high reliability. This series is offered in two distinct color variants: a blue LED based on InGaN chip technology and a brilliant red LED based on AlGaInP chip technology. The primary design philosophy centers on enabling smaller printed circuit board (PCB) footprints, higher component packing density, and ultimately contributing to the development of more compact and lightweight end-user equipment.

1.1 Core Features and Advantages

The device incorporates several key features that enhance its usability and performance in automated manufacturing environments. It is supplied on 8mm tape wound onto 7-inch diameter reels, making it fully compatible with standard automatic pick-and-place assembly equipment. The component is qualified for use with both infrared (IR) and vapor phase reflow soldering processes, which are prevalent in high-volume electronics production. It is constructed as a mono-color type, is lead-free (Pb-free), and complies with major environmental regulations including the EU RoHS directive, REACH regulation, and halogen-free requirements (with Bromine <900 ppm, Chlorine <900 ppm, and their sum <1500 ppm). The inherent small size and lightweight nature of this SMD package make it an ideal choice for applications where space and weight are critical constraints.

1.2 Target Applications

The versatility of the 18-225 LED series allows for deployment across a broad spectrum of applications. Common uses include backlighting for instrument panel dashboards and membrane switches. In telecommunications equipment, it serves effectively as status indicators and keypad backlights in devices such as telephones and fax machines. It is also suitable for providing flat, uniform backlighting for liquid crystal displays (LCDs), switch legends, and symbols. Finally, its general-purpose characteristics make it a reliable choice for a wide array of other indicator and illumination tasks in consumer, industrial, and automotive electronics.

2. Technical Specifications Deep Dive

2.1 Absolute Maximum Ratings

Operating the device beyond these limits may cause permanent damage. The maximum reverse voltage (V_R) is 5V for both color variants. The continuous forward current (I_F) rating is 25 mA for both the B6 (blue) and R6 (red) LEDs. For pulsed operation, the peak forward current (I_FP) at a duty cycle of 1/10 and 1 kHz frequency is 100 mA for the B6 and 60 mA for the R6. The maximum power dissipation (P_d) is 150 mW for B6 and 60 mW for R6. The electrostatic discharge (ESD) withstand voltage, per the Human Body Model (HBM), is 150V for B6 and a significantly higher 2000V for R6. The operating temperature range (T_opr) is from -40°C to +85°C, while the storage temperature range (T_stg) is slightly wider at -40°C to +90°C. The device can withstand soldering temperatures of 260°C for 10 seconds during reflow or 350°C for 3 seconds during hand soldering.

2.2 Electro-Optical Characteristics

All parameters are specified at an ambient temperature (T_a) of 25°C and a forward current (I_F) of 5 mA, unless otherwise noted. The typical luminous intensity (I_v) for both B6 and R6 is 28.5 mcd, with a minimum of 18.0 mcd. The viewing angle (2θ_1/2) is typically 120 degrees. For the B6 (blue) LED, the peak wavelength (λ_p) is 468 nm and the dominant wavelength (λ_d) is 470 nm, with a spectral bandwidth (Δλ) of 35 nm. For the R6 (red) LED, the peak wavelength is 632 nm, the dominant wavelength is 624 nm, and the spectral bandwidth is 20 nm. The forward voltage (V_F) ranges from 2.7V to 3.7V (typical 3.3V) for B6, and from 1.7V to 2.4V (typical 2.0V) for R6. The maximum reverse current (I_R) at V_R=5V is 50 μA for B6 and 10 μA for R6. Important notes include a luminous intensity tolerance of ±11%, a dominant wavelength tolerance of ±1 nm, and a forward voltage tolerance of ±0.10V. Reverse voltage testing is for characterization only; the device should not be operated in reverse bias.

3. Performance Curve Analysis

The datasheet provides a comprehensive set of characteristic curves for both LED types, which are essential for circuit design and thermal management.

3.1 Forward Current vs. Forward Voltage (I-V Curve)

The I-V curves illustrate the relationship between the current flowing through the LED and the voltage drop across it. These curves are non-linear, typical of diode behavior. For the B6 blue LED, the voltage rises sharply after exceeding approximately 2.7V. For the R6 red LED, this turn-on occurs around 1.7V. Designers use these curves to select appropriate current-limiting resistors to ensure stable operation at the desired drive current.

3.2 Luminous Intensity vs. Forward Current

These graphs show how light output increases with drive current. The relationship is generally linear within the recommended operating range but will saturate at very high currents. This data is crucial for determining the required drive current to achieve a specific brightness level.

3.3 Luminous Intensity vs. Ambient Temperature

These curves demonstrate the thermal dependence of light output. Luminous intensity typically decreases as the junction temperature of the LED increases. Understanding this derating is vital for applications that operate over a wide temperature range or in high-ambient-temperature environments, ensuring consistent brightness performance.

3.4 Forward Current Derating Curve

This graph specifies the maximum allowable continuous forward current as a function of the ambient temperature. To prevent overheating and ensure long-term reliability, the drive current must be reduced when operating at elevated temperatures. The curve provides the necessary guidelines for this thermal derating.

3.5 Spectrum Distribution

The spectral plots display the relative radiant power as a function of wavelength. The B6 blue LED shows a primary peak around 468 nm. The R6 red LED shows a primary peak around 632 nm. The width of these peaks, indicated by the spectral bandwidth parameter, affects the color purity of the emitted light.

3.6 Radiation Diagram

The polar radiation patterns depict the spatial distribution of light intensity. The typical 120-degree viewing angle is confirmed by these diagrams, which show the angular width at which the luminous intensity drops to half of its peak value (on-axis). This information is key for optical design, determining how the light will be perceived or collected.

4. Mechanical and Package Information

4.1 Package Dimensions

The 18-225 LED features a compact surface-mount package. Key dimensions include a body length of 1.6 mm, a width of 0.8 mm, and a height of 0.7 mm (with a tolerance of ±0.1 mm). The component has a low profile, with a typical thickness of 0.5 mm. The datasheet provides detailed top, side, and bottom views with all critical measurements clearly labeled. The polarity is indicated by a cathode mark on the package.

4.2 Recommended Soldering Pad Layout

A suggested land pattern (footprint) for PCB design is provided. The pad dimensions are given as a reference: typically 0.8 mm by 0.8 mm for the anode and cathode pads, with a gap of 0.4 mm between them. The documentation explicitly states that this is a suggested layout and should be modified based on individual manufacturing processes, PCB material, and thermal requirements. Adherence to these guidelines promotes reliable solder joint formation and proper thermal dissipation during reflow.

5. Soldering and Assembly Guidelines

5.1 Reflow Soldering Profile

For lead-free soldering, a specific temperature profile is recommended. The pre-heating zone should ramp from ambient to 150-200°C over 60-120 seconds. The time above the solder liquidus temperature (217°C) should be maintained for 60-150 seconds. The peak temperature should not exceed 260°C, and the time within 5°C of this peak should be limited to a maximum of 10 seconds. The maximum ramp-up rate to the peak is 6°C per second, and the maximum cooling rate from the peak is 3°C per second. It is critical that reflow soldering is not performed more than two times on the same device to avoid thermal damage to the internal die and wire bonds.

5.2 Storage and Moisture Sensitivity

The LEDs are packaged in a moisture-resistant barrier bag with desiccant to prevent absorption of ambient humidity. The unopened bag should be stored at 30°C or less and 90% relative humidity (RH) or less. Once the bag is opened, the components have a "floor life" of 1 year when stored at 30°C/60%RH or less. Any unused devices should be resealed in a moisture-proof package. If the desiccant indicator shows saturation or the storage time is exceeded, a baking treatment at 60 ±5°C for 24 hours is required before the components can be subjected to reflow soldering to prevent "popcorning" or delamination.

5.3 Critical Usage Precautions

Over-current Protection: LEDs are current-driven devices. An external current-limiting resistor is mandatory in series with the LED. Even a small increase in forward voltage can cause a large, potentially destructive increase in current if not properly limited. The circuit design must account for the power supply's voltage tolerance and the LED's forward voltage variation.
Handling: Standard ESD (electrostatic discharge) precautions should be observed during handling and assembly, especially for the B6 variant which has a lower ESD rating.

6. Packaging and Ordering Information

6.1 Reel and Tape Specifications

The components are delivered in embossed carrier tape with a width of 8 mm, wound onto a standard 7-inch (178 mm) diameter reel. Each reel contains 3000 pieces. Detailed dimensions for the carrier tape pockets, cover tape, and reel hub are provided to ensure compatibility with automated feeding equipment.

6.2 Label Explanation

The reel label contains several key identifiers: the Customer's Product Number (CPN), the manufacturer's Product Number (P/N), the Packing Quantity (QTY), and the Lot Number (LOT No.). It also includes binning information for critical parameters: Luminous Intensity Rank (CAT), Chromaticity Coordinates & Dominant Wavelength Rank (HUE), and Forward Voltage Rank (REF). This binning allows for the selection of LEDs with tightly grouped characteristics for applications requiring color or brightness consistency.

7. Application Design Considerations

7.1 Circuit Design

The fundamental design task is to calculate the series resistor (R_s) value. The formula is R_s = (V_supply - V_F) / I_F, where V_F is the forward voltage of the LED at the desired current I_F. The power rating of the resistor must be sufficient: P_resistor = (I_F)^2 * R_s. Designers must use the maximum V_F from the datasheet to ensure the current does not exceed the maximum rating even under worst-case conditions. For example, driving the R6 red LED at 20 mA from a 5V supply: Using max V_F=2.4V, R_s = (5V - 2.4V) / 0.020A = 130 Ohms. The nearest standard value (e.g., 130 or 120 Ohms) would be selected, and its power rating checked.

7.2 Thermal Management

While the package is small, effective thermal management is still important for longevity and stable output. The power dissipated in the LED is P_LED = V_F * I_F. This heat must be conducted away through the solder pads and into the PCB copper. Using the recommended or larger pad sizes, and connecting them to copper pour areas (thermal reliefs), can significantly improve heat dissipation, especially when operating at higher currents or in warm environments.

7.3 Optical Integration

The wide 120-degree viewing angle makes this LED suitable for applications requiring broad, diffuse illumination. For more directed light, secondary optics such as lenses or light pipes may be employed. The package dimensions and radiation pattern data are essential for designing these optical elements.

8. Technical Comparison and Selection Guidance

The 18-225 series offers two distinct technologies in one package footprint. The B6 (InGaN) blue LED provides a shorter wavelength, higher forward voltage, and higher power dissipation capability but has a lower ESD tolerance. The R6 (AlGaInP) brilliant red LED offers a longer wavelength, lower forward voltage, and superior ESD robustness but has a lower maximum power dissipation. The choice between them is primarily driven by the required color. For applications where both colors might be used on the same board, the differing forward voltages necessitate separate current-limiting resistor calculations for each color channel to achieve uniform current and thus controlled brightness.

9. Frequently Asked Questions (FAQ)

Q: Can I drive this LED directly from a microcontroller GPIO pin?
A: Generally, no. Most microcontroller pins cannot source or sink the 20-25 mA typical operating current of these LEDs. An external current-limiting resistor and often a transistor driver are required.
Q: Why is the ESD rating different for the blue and red versions?
A> The difference stems from the inherent material properties of the InGaN (blue) and AlGaInP (red) semiconductor chips. AlGaInP structures are typically more robust against electrostatic discharge.
Q: What does \"water clear\" resin color mean?
A: It indicates the encapsulating lens of the LED is transparent, not diffused or tinted. This allows the true chip color (blue or red) to be emitted, often resulting in higher perceived brightness and more saturated color compared to a diffused package.
Q: How do I interpret the binning codes (CAT, HUE, REF) on the label?
A: These codes correspond to specific ranges of luminous intensity, dominant wavelength/chromaticity, and forward voltage, respectively. They allow manufacturers to group LEDs with similar performance. For critical applications, consult the manufacturer's detailed binning document to select the appropriate code for your needs.