Reverse Mount SMD LED Yellow 588nm - Package Dimensions 3.2x1.6x1.1mm - Forward Voltage 2.4V - Power Dissipation 75mW - English Technical Document

1. Product Overview

This document details the specifications for a high-brightness, reverse-mount Surface Mount Device (SMD) Light Emitting Diode (LED). The device utilizes an Aluminum Indium Gallium Phosphide (AlInGaP) semiconductor chip to produce yellow light, encapsulated in a water-clear lens package. Its primary design is for automated assembly processes, being supplied on 8mm tape wound onto 7-inch reels. Key features include compliance with RoHS directives, compatibility with infrared and vapor phase reflow soldering, and suitability for use in a wide range of electronic applications where reliable, bright indicator lighting is required.

2. Technical Parameters Deep Objective Interpretation

2.1 Absolute Maximum Ratings

The device's operational limits are defined at an ambient temperature (Ta) of 25°C. The maximum continuous DC forward current is 30 mA. The peak forward current, permissible under pulsed conditions (1/10 duty cycle, 0.1ms pulse width), is 80 mA. The maximum power dissipation is 75 mW. For ambient temperatures above 50°C, the allowable forward current must be derated linearly at a rate of 0.4 mA per degree Celsius. The maximum reverse voltage that can be applied is 5 V. The device can operate within an ambient temperature range of -30°C to +85°C and can be stored between -40°C and +85°C. The infrared soldering condition is specified as a peak temperature of 260°C for a maximum of 5 seconds.

2.2 Electro-Optical Characteristics

Measured at Ta=25°C and a forward current (IF) of 20 mA, the key performance parameters are as follows. The luminous intensity (Iv) has a typical value, but is binned from a minimum of 28.0 mcd to a maximum of 450.0 mcd. The viewing angle (2θ1/2), defined as the full angle at which intensity drops to half its axial value, is 70 degrees. The peak emission wavelength (λP) is 588.0 nm. The dominant wavelength (λd), which defines the perceived color, is 587.0 nm. The spectral line half-width (Δλ) is 17 nm. The forward voltage (VF) typically measures 2.4 V, with a maximum of 2.4 V at the test condition. The reverse current (IR) is a maximum of 10 µA at a reverse voltage (VR) of 5 V. The junction capacitance (C) is 40 pF measured at zero bias and 1 MHz.

3. Binning System Explanation

The luminous output of the LEDs is categorized into bins to ensure consistency in application. The binning is based on the minimum and maximum luminous intensity measured at 20 mA. The bin codes and their corresponding ranges are: N (28.0-45.0 mcd), P (45.0-71.0 mcd), Q (71.0-112.0 mcd), R (112.0-180.0 mcd), S (180.0-280.0 mcd), and T (280.0-450.0 mcd). A tolerance of +/-15% is applied to each intensity bin. This system allows designers to select components appropriate for the required brightness level in their design.

4. Performance Curve Analysis

The datasheet references typical performance curves which are essential for design analysis. These curves, plotted against ambient temperature unless noted, would typically illustrate the relationship between forward current and luminous intensity, the variation of forward voltage with temperature, and the relative radiant power versus wavelength (spectral distribution). Analyzing the IV curve helps in designing the current-limiting circuitry, while the temperature derating curve is critical for ensuring reliability under varying thermal conditions. The spectral distribution curve confirms the monochromatic nature of the light output centered around 588 nm.

5. Mechanical and Packaging Information

5.1 Package Dimensions and Polarity

The LED conforms to a standard EIA package outline. Key dimensions include the overall length, width, and height. The cathode is typically identified by a visual marker such as a notch or a green marking on the package. Detailed dimensioned drawings are provided in the datasheet, with all measurements in millimeters and a standard tolerance of ±0.10 mm unless otherwise specified.

5.2 Tape and Reel Specifications

For automated pick-and-place assembly, the components are supplied in embossed carrier tape. The tape width is 8 mm. The components are loaded into pockets and sealed with a top cover tape. They are wound onto reels with a 7-inch (178 mm) diameter. Each full reel contains 3000 pieces. For quantities less than a full reel, a minimum packing quantity of 500 pieces applies for remainders. The packaging conforms to ANSI/EIA 481-1-A-1994 specifications, with a maximum allowance of two consecutive missing components in the tape.

6. Soldering and Assembly Guidelines

6.1 Reflow Soldering Profiles

Two suggested infrared (IR) reflow profiles are provided: one for standard (tin-lead) solder process and one for lead-free (Pb-free) solder process. The lead-free profile is specifically recommended for use with SnAgCu solder paste. The profiles define critical parameters including preheat temperature and time, time above liquidus, peak temperature, and cooling rate. Adherence to these profiles, particularly the maximum peak temperature of 260°C for 5 seconds, is crucial to prevent thermal damage to the LED package and semiconductor die.

6.2 Cleaning and Storage

If cleaning is necessary after soldering, only specified solvents should be used. Immersing the LED in ethyl alcohol or isopropyl alcohol at normal temperature for less than one minute is acceptable. Unspecified chemicals may damage the epoxy lens. For storage, LEDs should be kept in an environment not exceeding 30°C and 70% relative humidity. Components removed from their original moisture-barrier bag should be reflow-soldered within one week. For longer storage outside the original packaging, they must be stored in a sealed container with desiccant or in a nitrogen ambient and require a baking procedure (approximately 60°C for 24 hours) before assembly to remove absorbed moisture.

7. Application Suggestions

7.1 Typical Application Circuits

LEDs are current-driven devices. To ensure uniform brightness when driving multiple LEDs, it is strongly recommended to use a series current-limiting resistor for each LED, as shown in the datasheet's "Circuit model A." Driving multiple LEDs in parallel directly from a voltage source ("Circuit model B") is discouraged because small variations in the forward voltage (Vf) characteristic of individual LEDs can lead to significant differences in current and, consequently, brightness. The series resistor stabilizes the current through each LED independently.

7.2 Electrostatic Discharge (ESD) Protection

The LED is sensitive to electrostatic discharge. ESD damage can manifest as high reverse leakage current, low forward voltage, or failure to illuminate at low currents. Preventive measures are mandatory during handling and assembly: personnel should wear conductive wrist straps or anti-static gloves; all equipment, workstations, and storage racks must be properly grounded. An ionizer can be used to neutralize static charge that may accumulate on the plastic lens. Verifying for ESD damage involves checking for illumination and measuring Vf at low current levels.

8. Design Considerations and Cautions

The device is intended for general electronic equipment. Applications requiring exceptional reliability, especially where failure could risk life or health (e.g., aviation, medical devices), require prior consultation. The drive method must respect absolute maximum ratings for current and power, incorporating necessary derating for elevated ambient temperatures. Thermal management on the PCB should be considered if operating near maximum ratings. The soldering pad layout must follow the suggested dimensions to ensure proper mechanical alignment and solder joint formation during reflow.

9. Technology Introduction and Trends

This LED uses AlInGaP technology, which is known for high efficiency and stability in producing red, orange, and yellow light. The "reverse mount" design indicates the light-emitting surface is on the side opposite the mounting pads, which can be advantageous for specific optical designs or space-constrained layouts where side-emitting light is required. The trend in SMD LEDs continues towards higher luminous efficacy (more light output per electrical watt), improved color consistency through tighter binning, and enhanced reliability under harsh environmental conditions, including higher temperature soldering profiles required for lead-free assembly.