LED SMD 3210 Yellow / Yellow-Green Specification - Dimensions 3.2x1.0x1.48mm - Voltage 1.8-2.4V - Power 48mW - English Technical Document

1. Product Overview

This document details the specifications for a compact, surface-mount LED component. The device is fabricated using a combination of a yellow-green chip and a yellow chip, housed in a miniature 3.2mm x 1.0mm x 1.48mm package. It is designed for general-purpose indicator and display applications where space is at a premium and reliable performance is required.

1.1 Core Advantages

• Extremely Wide Viewing Angle: Features a typical viewing angle (2θ1/2) of 140 degrees, ensuring high visibility from various positions.
• SMT Compatibility: Fully suitable for all standard Surface Mount Technology (SMT) assembly and solder reflow processes.
• Moisture Sensitivity: Classified as Moisture Sensitivity Level (MSL) 3, which defines specific handling and baking requirements prior to reflow soldering.
• Environmental Compliance: The product is compliant with RoHS (Restriction of Hazardous Substances) directives.

1.2 Target Applications

• Status and power indicators in consumer electronics, appliances, and industrial equipment.
• Backlighting for switches, buttons, and symbols on control panels.
• General-purpose illumination and display applications requiring compact, reliable light sources.

2. In-Depth Technical Parameter Analysis

2.1 Electrical & Optical Characteristics

The following parameters are specified at a standard test condition of an ambient temperature (Ts) of 25°C and a forward current (IF) of 20mA, unless otherwise noted.

2.1.1 Optical Parameters

• Dominant Wavelength (λd): Defines the perceived color.
  • Yellow (Y): Available in two bins: Code 2K (585-590 nm) and Code 2L (590-595 nm).
  • Yellow-Green (YG): Available in three bins: Code A20 (562.5-565 nm), B10 (565-567.5 nm), and B20 (567.5-570 nm).
• Spectral Half Bandwidth (Δλ): Approximately 15 nm for both Yellow and Yellow-Green variants, indicating a relatively pure color emission.
• Luminous Intensity (Iv): The light output measured in millicandelas (mcd).
  • Yellow (Y): Offered in three intensity grades: 1AP (90-120 mcd), G20 (120-150 mcd), and 1AW (150-200 mcd).
  • Yellow-Green (YG): Code 1EO specifies an intensity range of 30-50 mcd.

2.1.2 Electrical Parameters

• Forward Voltage (VF): Ranges from 1.8V to 2.4V for both color types at 20mA. The typical value is around the midpoint of this range.
• Reverse Current (IR): Maximum of 10 μA when a reverse voltage (VR) of 5V is applied, indicating good diode characteristics.
• Thermal Resistance (RθJ-S): Junction-to-solder point thermal resistance is specified at 450 °C/W. This parameter is critical for calculating the junction temperature rise during operation.

2.2 Absolute Maximum Ratings

Stresses beyond these limits may cause permanent damage to the device.

• Power Dissipation (Pd): 48 mW
• Continuous Forward Current (IF): 20 mA
• Peak Forward Current (IFP): 60 mA (pulsed, 1/10 duty cycle, 0.1ms pulse width)
• Electrostatic Discharge (ESD) HBM: 2000 V
• Operating Temperature (Topr): -40°C to +85°C
• Storage Temperature (Tstg): -40°C to +85°C
• Maximum Junction Temperature (Tj): 95°C

3. Performance Curve Analysis

The specification includes several characteristic graphs that provide deeper insight into the LED's behavior under different conditions.

3.1 Forward Current vs. Forward Voltage (IV Curve)

The curve shows a typical exponential relationship. The forward voltage increases with current, starting from the threshold voltage. Designers use this to select appropriate current-limiting resistors for their drive circuits.

3.2 Forward Current vs. Relative Luminous Intensity

This graph demonstrates that light output increases approximately linearly with forward current up to the rated maximum. Operating above 20mA yields diminishing returns and risks exceeding thermal limits.

3.3 Temperature Dependence

• Pin Temperature vs. Relative Intensity: Luminous intensity decreases as the pin (and thus junction) temperature increases. This is a fundamental characteristic of LEDs due to increased non-radiative recombination at higher temperatures.
• Pin Temperature vs. Forward Current: Shows the derating of maximum allowable forward current as the ambient/pin temperature rises to keep the junction temperature within the 95°C limit.

3.4 Forward Current vs. Dominant Wavelength

Separate graphs for Yellow and Yellow-Green LEDs show that the dominant wavelength shifts slightly with drive current. For Yellow-Green, wavelength increases from ~567.5nm to ~574.5nm as current rises from 0 to 30mA. For Yellow, it increases from ~587.5nm to ~592.5nm. This shift should be considered in color-critical applications.

4. Mechanical & Package Information

4.1 Package Dimensions

The LED conforms to a 3210 package footprint (3.2mm length x 1.0mm width). The overall height is 1.48mm. Detailed top, side, bottom, and polarity views are provided in the specification drawings. All dimension tolerances are ±0.2mm unless otherwise specified.

4.2 Polarity Identification & Soldering Pattern

The cathode (negative) terminal is clearly marked. A recommended soldering land pattern (footprint) is provided for PCB design, with pad dimensions of 1.30mm x 0.80mm and a spacing (pitch) of 2.00mm between pads. A 0.30mm gap between the pad and the component body is recommended.

5. Soldering & Assembly Guidelines

5.1 SMT Reflow Soldering Instructions

The component is designed for lead-free reflow soldering processes. Due to its MSL 3 rating, the device must be baked according to the relevant IPC/JEDEC standard (typically 125°C for 4-8 hours) if the moisture barrier bag has been opened or the exposure time limit has been exceeded. The specific reflow temperature profile (preheat, soak, reflow peak temperature, and cooling rates) should follow the recommendations for similar SMD components and the PCB assembly specifications. The maximum body temperature during soldering should not exceed the rated storage temperature.

5.2 Handling Precautions

• Always handle LEDs with ESD (Electrostatic Discharge) precautions.
• Avoid mechanical stress on the lens and leads.
• Do not use solvents that may damage the epoxy lens (e.g., ketones) for cleaning.
• Follow the moisture-sensitive packaging procedures strictly.

6. Packaging & Reliability

6.1 Packaging Specification

The LEDs are supplied in embossed carrier tape on reels for automated pick-and-place assembly. The specification includes detailed dimensions for the carrier tape pockets, reel diameter, and hub size. A label specification for the reel is also defined.

6.2 Moisture-Resistant Packing

The reels are packed in moisture barrier bags with desiccant and a humidity indicator card to maintain the MSL 3 integrity during storage and transport.

6.3 Reliability Test Items

The document references standard reliability test conditions, which likely include tests such as:

• High Temperature Storage Life
• Low Temperature Storage
• Temperature Cycling
• Humidity Testing
• Solder Heat Resistance

7. Application Suggestions & Design Considerations

7.1 Circuit Design

• Always use a series current-limiting resistor. Calculate the resistor value using R = (Vsupply - VF) / IF, where VF is the typical or maximum forward voltage from the datasheet to ensure current does not exceed 20mA.
• For constant brightness over temperature or in multi-LED arrays, consider using a constant current driver instead of a simple voltage source with a resistor.
• Account for the forward voltage tolerance when designing for low-voltage supplies to ensure adequate current drive.

7.2 Thermal Management

While the package is small, thermal management is crucial for reliability. The 450 °C/W thermal resistance means that at the full 20mA drive (approx. 48mW power dissipation), the junction temperature will be about 21.6°C above the solder point temperature (48mW * 450°C/W). Ensure the PCB can dissipate this heat, especially in high ambient temperatures or enclosed spaces, to keep Tj below 95°C.

7.3 Optical Design

The 140-degree viewing angle makes this LED suitable for applications requiring wide-angle visibility without secondary optics. For directed light, external lenses or light pipes may be necessary.

8. Technical Comparison & Differentiation

The primary differentiators of this component are its compact 3210 footprint combined with a relatively high luminous intensity for its size, particularly in the Yellow version. The availability of precise wavelength and intensity bins (e.g., YG A20/B10/B20) allows for better color consistency in batch production compared to LEDs with wider bins. The MSL 3 rating offers a balance between moisture protection and the need for pre-baking before assembly, which is common for many SMD packages.

9. Frequently Asked Questions (Based on Technical Parameters)

9.1 Can I drive this LED at 30mA for more brightness?

Answer: No. The Absolute Maximum Rating for continuous forward current is 20mA. Exceeding this rating will cause excessive junction temperature, leading to accelerated lumen depreciation and potentially catastrophic failure. Use the pulsed current rating (60mA) only for very short duty cycles as specified.

9.2 Why does the luminous intensity of the Yellow-Green LED seem lower than the Yellow?

Answer: This is related to the spectral sensitivity of the human eye (photopic response). The eye is most sensitive to green light (~555 nm). Yellow-Green (565-570 nm) is close to peak sensitivity, so less radiant power is needed to achieve a given perceived brightness (luminous intensity in mcd). The Yellow light (585-595 nm) is in a region of lower eye sensitivity, requiring more radiant power to achieve the same perceived brightness, hence the higher mcd ratings for similar chip technology and drive current.

9.3 How do I select the correct bin for my application?

Answer: For color-critical applications (e.g., status indicators that must match a specific corporate color or other LEDs on a panel), specify the tightest wavelength bin that meets your cost target (e.g., YG B10 instead of the wider A20 range). For general indication where absolute color is less critical, the standard or wider bins are acceptable. Similarly, select the intensity bin based on the required brightness and the drive current you plan to use.

10. Practical Use Case Example

Scenario: Designing a compact IoT sensor module with a multi-color status LED. Space is extremely limited on the PCB.

Implementation: The 3210 package is ideal. A Yellow-Green LED (e.g., bin B20, 567.5-570nm) could be used for a "power-on/active" indicator. A Yellow LED (bin 2L, 590-595nm) could indicate a "warning" or "standby" state. Both can be driven from the microcontroller's GPIO pins (3.3V) using separate current-limiting resistors. Calculation for the Yellow LED (assuming VF typ=2.1V, target IF=15mA for longer life): R = (3.3V - 2.1V) / 0.015A = 80 Ohms. Use the next standard value (82 Ohms). The actual current will be slightly lower, and the intensity will be proportionally lower than the 20mA rating, which is acceptable for a status indicator.

11. Operating Principle

This LED operates on the principle of electroluminescence in semiconductor materials. When a forward voltage exceeding the diode's threshold is applied, electrons and holes are injected into the active region of the semiconductor chip(s). Their recombination releases energy in the form of photons (light). The specific materials (e.g., Aluminum Gallium Indium Phosphide - AlGaInP for yellow/red, or Gallium Phosphide - GaP variants for green) determine the bandgap energy and thus the wavelength (color) of the emitted light. The package incorporates an epoxy lens that shapes the light output and provides environmental protection.

12. Technology Trends

The market for SMD LEDs like the 3210 continues to demand: Increased Efficiency: Higher luminous efficacy (more light output per electrical watt) to enable brighter indicators or lower power consumption. Miniaturization: Even smaller packages (e.g., 2016, 1515) while maintaining or improving optical performance. Improved Color Consistency: Tighter binning tolerances for both wavelength and intensity to reduce color variation in end products without manual sorting. Enhanced Reliability: Improved materials and packaging techniques to withstand higher reflow temperatures (for lead-free processes) and harsher operating environments. Integrated Solutions: Growth of LED components with built-in current regulation (constant current LED drivers) or control circuitry (addressable RGB LEDs), though the basic indicator LED described here remains a fundamental and widely used component.