Surface Mount LED Lamp LTWMR4DZ3KA Datasheet - Package 4.2x4.2x6.9mm - Voltage 2.6-3.3V - White Color - English Technical Document

1. Product Overview

This document details the specifications for a high-brightness surface mount LED lamp. Designed for automated assembly processes, this component offers superior optical performance in a compact package suitable for demanding signage applications.

1.1 Core Advantages and Product Positioning

The primary advantage of this LED is its integrated optical design. The package features a lens that provides a controlled, narrow radiation pattern, eliminating the need for secondary optics in many applications. This results in a more streamlined design and potentially lower system cost. The device is constructed using advanced epoxy materials that provide excellent moisture resistance and UV protection, enhancing its reliability for both indoor and outdoor use. It is fully compliant with RoHS, lead-free, and halogen-free directives.

1.2 Target Market and Applications

This LED is specifically engineered for high-visibility signage. Its key application areas include video message signs, various traffic signs, and general message display boards. The combination of high luminous intensity and a controlled viewing angle makes it ideal for creating bright, legible displays with efficient light utilization.

2. In-Depth Technical Parameter Analysis

A comprehensive analysis of the device's operational limits and performance under standard conditions.

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.

• Power Dissipation (Pd): 100 mW maximum. This is the total power the package can dissipate as heat.
• Forward Current: A DC forward current (IF) of 30 mA is the maximum continuous rating. A peak forward current of 100 mA is permissible only under pulsed conditions (duty cycle ≤ 1/10, pulse width ≤ 10ms).
• Thermal Derating: The maximum DC forward current must be linearly reduced from its 30mA rating at 25°C at a rate of 0.54 mA per degree Celsius for ambient temperatures (TA) above 55°C.
• Temperature Ranges: The device is rated for operation from -40°C to +85°C and can be stored from -40°C to +100°C.
• Reflow Soldering: The package can withstand a peak temperature of 260°C for a maximum of 10 seconds during the reflow soldering process.

2.2 Electro-Optical Characteristics

These parameters are measured at an ambient temperature (TA) of 25°C and a forward current (IF) of 20 mA, unless otherwise specified.

• Luminous Intensity (Iv): Ranges from a minimum of 8500 mcd to a maximum of 21000 mcd, with a typical value of 15000 mcd. The Iv value is binned, and the classification code is marked on the packaging.
• Viewing Angle (2θ1/2): Defined as the full angle at which the luminous intensity is half the axial (on-axis) intensity. The typical value is 35°, with a specified minimum of 30°.
• Forward Voltage (VF): Ranges from 2.6 V (min) to 3.3 V (max) at 20mA.
• Reverse Current (IR): Maximum of 10 μA when a reverse voltage (VR) of 5V is applied. It is critical to note that the device is not designed for operation in reverse bias; this test condition is for characterization only.

3. Binning System Specification

To ensure consistency in application, the LEDs are sorted into bins based on key performance parameters.

3.1 Luminous Intensity Binning

LEDs are classified into three primary bins based on their measured luminous intensity at 20mA:
- Bin Y: 8500 - 11500 mcd
- Bin Z: 11500 - 16000 mcd
- Bin 1: 16000 - 21000 mcd
A tolerance of ±15% applies to the limits of each bin.

3.2 Chromaticity (Hue) Binning

The white color point is controlled through chromaticity coordinate bins defined on the CIE 1931 (x, y) diagram. The datasheet specifies several hue ranks (e.g., 6U, 6L, 7U, 7L, 8U, 8L), each defining a quadrilateral region on the chromaticity chart. This allows designers to select LEDs with tightly controlled color consistency. The measurement allowance for color coordinates is ±0.01.

4. Mechanical and Package Information

4.1 Outline Dimensions

The LED features a rectangular package with a dome lens. Key dimensions include:
- Package Body: 4.2mm ±0.2mm x 4.2mm ±0.2mm.
- Total Height: 6.9mm ±0.5mm.
- Lead spacing and protrusion details are provided in the detailed drawing. All dimensions include imperial equivalents in brackets.

4.2 Polarity Identification and Pinout

The device has three pins (P1, P2, P3). P1 and P3 are designated as the Anode (+), and P2 is designated as the Cathode (-). Correct polarity must be observed during circuit board layout and assembly.

4.3 Recommended Solder Pad Pattern

A land pattern design is suggested for PCB layout. The pattern accounts for the three pins and includes a thermal pad note. The pad associated with pin P3 is specifically recommended for connection to a heat sink or cooling mechanism to aid in thermal management during operation.

5. Assembly, Handling, and Reliability Guidelines

5.1 Moisture Sensitivity and Storage

This component is classified as Moisture Sensitivity Level (MSL) 3 per JEDEC J-STD-020.
- LEDs in an unopened moisture barrier bag can be stored for up to 12 months at <30°C and 90% RH.
- Once the bag is opened, the components must be kept at <30°C and 60% RH and must be soldered within 168 hours (7 days).
- Baking at 60°C ±5°C for 20 hours is required if the humidity indicator card shows >10% RH, if the floor life exceeds 168 hours, or if components are exposed to >30°C and 60% RH. Baking should be performed only once.

5.2 Soldering Process

Reflow Soldering (Recommended):
- Pre-heat: 150-200°C.
- Maximum pre-heat time: 120 seconds.
- Peak temperature: 260°C maximum.
- Time above 260°C: 10 seconds maximum.
- The device is designed for reflow soldering and is not suitable for dip soldering. Reflow should not be performed more than two times.
Hand Soldering (Iron):
- Maximum iron temperature: 315°C.
- Maximum soldering time per pin: 3 seconds.
- This should be done one time only.

5.3 Cleaning

If cleaning is necessary after soldering, only alcohol-based solvents such as isopropyl alcohol (IPA) should be used.

6. Packaging and Ordering Information

6.1 Tape and Reel Packaging

The LEDs are supplied in embossed carrier tape on reels for automated pick-and-place assembly. The tape dimensions are specified to ensure compatibility with standard SMT equipment. Each full reel contains 1,000 pieces. The reel and tape are labeled to indicate the presence of Electrostatic Sensitive Devices (ESD), requiring safe handling procedures.

7. Application Notes and Design Considerations

7.1 Typical Application Circuits

In a typical application, the LED is driven by a constant current source to ensure stable luminous output and longevity. A simple series resistor can be used for basic applications, calculated based on the supply voltage (Vcc), the LED's forward voltage (VF), and the desired forward current (IF): R = (Vcc - VF) / IF. For example, with a 5V supply, a VF of 3.0V, and a target IF of 20mA, the resistor value would be (5V - 3.0V) / 0.02A = 100 Ohms. The power rating of the resistor must also be considered (P = (Vcc - VF) * IF). For high-reliability or precision applications, dedicated LED driver ICs are recommended.

7.2 Thermal Management

Although the power dissipation is relatively low (max 100mW), effective thermal management is crucial for maintaining performance and lifespan, especially in high-ambient-temperature environments or densely packed arrays. The recommended connection of the thermal pad (P3) to a copper pour on the PCB acts as a heat spreader. For designs requiring multiple LEDs, ensuring adequate spacing and possibly using metal-core PCBs (MCPCBs) should be considered to manage the collective thermal load.

7.3 Optical Integration

The integrated 35° viewing angle lens is a key feature. Designers should verify that this beam pattern meets their application's requirements for brightness uniformity and viewing cone. For wider viewing angles, a different LED model or secondary diffuser would be necessary. The narrow beam is advantageous for directing light efficiently onto a specific area, such as a sign face, with minimal spill.

8. Technical Comparison and Differentiation

Compared to standard SMD LEDs (e.g., PLCC packages), this device offers significantly higher luminous intensity in a through-hole lamp style form factor with a pre-collimated beam. This eliminates the cost and alignment complexity of adding a separate optical lens. Compared to other high-power LEDs, it operates at a lower current (20mA vs. 350mA+), simplifying driver design and reducing system thermal challenges while still delivering high brightness suitable for signage.

9. Frequently Asked Questions (FAQ)

Q: What is the difference between the Y, Z, and 1 intensity bins?
A: They represent different ranges of minimum luminous output. Bin 1 has the highest output (16000-21000 mcd), followed by Bin Z (11500-16000 mcd), and then Bin Y (8500-11500 mcd). Selection depends on the brightness requirement of the application.

Q: Can I drive this LED at 30mA continuously?
A: Yes, 30mA is the maximum rated DC forward current. However, at elevated ambient temperatures (above 55°C), the current must be derated as specified. For optimal longevity and stable performance, operating at or below the typical 20mA is recommended.

Q: Why is there a 168-hour floor life after opening the bag?
A: The MSL 3 rating indicates the package absorbs moisture from the air. After 168 hours at factory floor conditions (<30°C/60% RH), the absorbed moisture may reach a level that could cause package damage (like cracking or delamination) during the high-temperature reflow soldering process. Exceeding this time requires baking to remove the moisture.

Q: Is an anti-static (ESD) precaution necessary?
A> Yes. The packaging is marked as containing Electrostatic Sensitive Devices. Standard ESD handling precautions, such as the use of grounded wrist straps and workstations, should be followed during manual handling to prevent damage from electrostatic discharge.

10. Operational Principles and Technology

This is a white LED based on InGaN (Indium Gallium Nitride) semiconductor technology. It generates blue light from the InGaN chip. This blue light then excites a phosphor layer inside the package. The phosphor down-converts a portion of the blue light into longer wavelengths (yellow, red), and the mixture of the remaining blue light and the phosphor-emitted light results in the perception of white light. The specific mix of phosphors determines the correlated color temperature (CCT) and chromaticity coordinates, which are controlled through the hue binning process. The water-clear epoxy package acts as both a protective enclosure and a primary optical element, shaping the light output into the specified viewing angle.