LTWMH4DSAKR LED Lamp Datasheet - Dimensions 4.2x4.2x6.2mm - Voltage 3.2V - Power 85mW - White Water Clear Package - English Technical Document

1. Product Overview

The LTWMH4DSAKR is a high-brightness, surface-mount LED lamp designed for demanding lighting applications. It is a white LED utilizing InGaN technology, packaged in a water-clear epoxy resin. The primary design focus is on providing a smooth radiation pattern and controlled viewing angles suitable for sign board applications without the need for additional secondary optics, offering a cost-effective and compact solution compared to standard SMD or PLCC packages.

1.1 Core Advantages and Target Market

This device offers several key advantages that make it suitable for professional lighting designs. It features high luminous intensity output combined with low power consumption, resulting in high efficiency. The package is constructed using advanced epoxy technology, which provides superior moisture resistance and UV protection, enhancing long-term reliability in various environments. The device is fully compliant with RoHS, lead-free, and halogen-free directives. Its primary target markets include video message signs, traffic signs, and general message signage where consistent, bright illumination and reliability are critical.

2. Technical Parameter Deep Dive

The following section provides a detailed analysis of the electrical, optical, and thermal characteristics of the LTWMH4DSAKR LED.

2.1 Absolute Maximum Ratings

These ratings define the limits beyond which permanent damage to the device may occur. They are specified at an ambient temperature (TA) of 25°C. The maximum power dissipation is 85 mW. The DC forward current should not exceed 25 mA. For pulsed operation, a peak forward current of 60 mA is permissible under specific conditions: duty cycle ≤ 1/10 and pulse width ≤ 10 ms. The device can operate within a temperature range of -40°C to +85°C and can be stored between -40°C and +100°C. For assembly, it can withstand reflow soldering with a peak temperature of 260°C for a maximum of 10 seconds. The DC forward current derates linearly at a rate of 0.55 mA per degree Celsius above 55°C.

2.2 Electrical and Optical Characteristics

These are the typical operating parameters measured at TA=25°C. The luminous intensity (Iv) ranges from a minimum of 3000 mcd to a maximum of 6000 mcd at a forward current (IF) of 20 mA. It is important to note that the Iv guarantee includes a ±15% testing tolerance. The viewing angle (2θ1/2) is typically 110°/50°, defined as the off-axis angle where intensity is half the axial value. The forward voltage (VF) typically measures 3.2V, with a range from 2.8V to 3.4V at IF=20mA. The reverse current (IR) is a maximum of 10 μA when a reverse voltage (VR) of 5V is applied. The chromaticity coordinates are typically x=0.32, y=0.33 on the CIE 1931 diagram. The device is classified as Moisture Sensitivity Level 3 (MSL3).

3. Binning System Explanation

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

3.1 Luminous Intensity Binning

The luminous output is categorized into two bins: Bin Code 'U' for intensities between 3000 mcd and 4200 mcd, and Bin Code 'V' for intensities between 4200 mcd and 6000 mcd. The tolerance for each bin limit is ±15%.

3.2 Forward Voltage Binning

The forward voltage is binned into three categories: Bin Code '2E' (2.8V to 3.0V), '3E' (3.0V to 3.2V), and '4E' (3.2V to 3.4V). A measurement allowance of ±0.1V is applied.

3.3 Chromaticity (Hue) Binning

The color coordinates are defined within specific regions on the CIE chromaticity diagram. Two hue ranks are specified: BB3 and BB4, each defining a quadrilateral area of acceptable x, y coordinates. A measurement allowance of ±0.01 is applied to the color coordinates.

4. Mechanical and Package Information

4.1 Outline Dimensions

The package has a body size of 4.2mm ±0.2mm in length and width. The total height is 6.2mm ±0.5mm. Key features include a protruded resin under the flange with a maximum height of 1.0mm. The lead spacing is measured where the leads emerge from the package body. All dimensions are in millimeters, with a general tolerance of ±0.25mm unless otherwise specified.

4.2 Polarity Identification

The device has three pins: P1 is designated as the Anode (+), P2 is the Cathode (-), and P3 has no electrical polarity. Correct identification is crucial for proper circuit operation.

5. Soldering and Assembly Guidelines

5.1 Storage and Handling

As an MSL3 device, specific handling procedures are required. LEDs in a sealed moisture barrier bag can be stored at <30°C and 90% RH for up to 12 months. After opening the bag, components must be kept under <30°C and 60% RH and must complete soldering 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 floor life exceeds 168 hours, or if exposed to >30°C and 60% RH. Baking should be performed only once. Unused LEDs should be re-sealed with desiccant.

5.2 Soldering Parameters

For reflow soldering, a peak temperature of 260°C maximum for 10 seconds maximum is allowed (maximum two reflow cycles). A pre-heat stage of 150-200°C for up to 120 seconds is recommended. For hand soldering with an iron, the temperature should not exceed 315°C, with a soldering time of 3 seconds maximum (one time only).

5.3 Cleaning

If cleaning is necessary, alcohol-based solvents such as isopropyl alcohol should be used.

6. Packaging and Ordering Information

6.1 Packing Specification

The LEDs are supplied on embossed carrier tape. The tape dimensions are specified, with pockets designed to hold the device securely. One reel contains 1,000 pieces. The reel is then placed in a moisture barrier bag along with a desiccant and a humidity indicator card.

6.2 Carton Packaging

Three moisture barrier bags (3,000 pcs total) are packed per inner carton. Ten inner cartons (30,000 pcs total) are packed per outer carton. The label \"ATTENTION: Electrostatic Sensitive Devices - Safe Handling Required\" is present on the packaging.

7. Application Suggestions

7.1 Typical Application Scenarios

This LED is well-suited for both indoor and outdoor signage applications, including video message signs, traffic signs, and general information displays. Its controlled viewing angle and high brightness make it ideal for applications requiring good visibility without excessive light spill.

7.2 Design Considerations

Designers should consider the forward voltage and current requirements to select appropriate current-limiting resistors or drivers. Thermal management is important; while the device has a derating curve, ensuring adequate PCB copper area for heat sinking will maximize lifetime and maintain light output. The MSL3 rating mandates strict adherence to the storage and baking guidelines before assembly to prevent popcorn cracking or other moisture-related damage during reflow.

8. Technical Comparison and Differentiation

Compared to standard SMD LEDs (like 3528 or 5050 packages) or PLCC packages, this device offers a key advantage: its integrated lens design provides a specific, narrow viewing angle (110°/50°) without requiring an external secondary optic. This simplifies the mechanical design of the final product, reduces part count, and can lower overall system cost. The water-clear package maximizes light extraction efficiency for the white phosphor-converted LED.

9. Frequently Asked Questions (Based on Technical Parameters)

Q: What is the typical operating current for this LED?

A: The electrical/optical characteristics are specified at IF=20mA, which is the standard test condition and a common operating point.

Q: How do I interpret the luminous intensity bin code?

A: The bin code (U or V) is marked on the packing bag and indicates the guaranteed minimum and maximum intensity range for that batch of LEDs, including a ±15% test tolerance.

Q: Can I drive this LED with a constant voltage source?

A: No. LEDs are current-driven devices. The forward voltage has a range (2.8V-3.4V). Driving with a constant voltage can lead to excessive current and device failure. Always use a constant current driver or a current-limiting resistor in series with a voltage source.

Q: What does MSL3 mean for my production process?

A: Moisture Sensitivity Level 3 means the components can be exposed to factory floor conditions (≤30°C/60% RH) for up to 168 hours (7 days) after the bag is opened before they require baking. You must plan your assembly schedule accordingly.

10. Design and Usage Case Study

Consider a design for an outdoor traffic information sign. The sign requires bright, white pixels that are clearly visible in daylight. The LTWMH4DSAKR's high luminous intensity (up to 6000 mcd) meets the brightness requirement. Its 110°/50° viewing angle ensures the light is directed towards the viewer on the road without wasting energy illuminating areas above or below the sign. The superior moisture resistance of the package is critical for long-term reliability in an outdoor, weather-exposed environment. The designer would create a PCB layout accommodating the 4.2x4.2mm footprint, implement a constant-current driver circuit set for 20mA per LED, and ensure the production line follows the MSL3 handling procedures to prevent yield loss during reflow soldering.

11. Operating Principle Introduction

The LTWMH4DSAKR is a white LED based on InGaN (Indium Gallium Nitride) semiconductor technology. The core of the device is a semiconductor chip that emits blue light when electrical current passes through it in the forward direction (electroluminescence). This blue light then strikes a phosphor coating inside the package. The phosphor absorbs a portion of the blue light and re-emits it as light of longer wavelengths (yellow, red). The combination of the remaining blue light and the phosphor-converted yellow/red light mixes to produce white light to the human eye. The water-clear epoxy lens surrounding the chip and phosphor is designed to efficiently extract this light while providing the desired beam angle.

12. Technology Trends and Context

The development of high-brightness white LEDs like the LTWMH4DSAKR is part of the broader solid-state lighting revolution. Key trends in this field include continuous improvements in luminous efficacy (lumens per watt), leading to lower power consumption for the same light output. There is also a focus on improving color rendering index (CRI) and color consistency (tighter binning). Packaging technology advances, as seen in this device's moisture-resistant epoxy and controlled lens geometry, aim to enhance reliability and optical performance while enabling miniaturization. The drive towards lead-free, halogen-free, and RoHS-compliant manufacturing reflects global environmental regulations and sustainability goals. Surface-mount technology itself allows for automated, high-volume assembly, reducing manufacturing costs for end products.