SMD LED 19-217/T7D-CT2V1N/3T Datasheet - Package 2.0x1.25x0.8mm - Voltage 2.7-3.7V - Power 110mW - Pure White - English Technical Document

1. Product Overview

The 19-217/T7D-CT2V1N/3T is a compact, surface-mount LED designed for modern electronic applications requiring reliable indicator or backlighting functionality. This mono-color, Pure White LED utilizes an InGaN chip encapsulated in a yellow diffused resin. Its primary advantage lies in its significantly reduced footprint compared to traditional lead-frame components, enabling higher packing density on PCBs, reduced storage requirements, and ultimately contributing to the miniaturization of end equipment. The lightweight construction further makes it ideal for portable and space-constrained applications.

1.1 Core Features and Compliance

The device is supplied in 8mm tape on 7-inch diameter reels, ensuring compatibility with standard automated pick-and-place assembly equipment. It is designed for use with both infrared and vapor phase reflow soldering processes. The product adheres to several critical environmental and safety standards: it is Pb-free, compliant with the EU RoHS directive, meets EU REACH requirements, and is classified as Halogen-Free, with Bromine (Br) and Chlorine (Cl) content each below 900 ppm and their sum below 1500 ppm. This makes it suitable for use in markets with stringent environmental regulations.

1.2 Target Applications

The LED is versatile and finds use in multiple sectors. Common applications include backlighting for automotive dashboards and switches, indicator and backlighting functions in telecommunication devices such as telephones and fax machines, flat backlighting for LCDs, switches, and symbols, and general-purpose indicator use where a small, bright white light source is required.

2. Technical Parameters: In-Depth Objective Interpretation

This section provides a detailed breakdown of the electrical, optical, and thermal limits and characteristics of the LED, which are fundamental for reliable circuit design and system integration.

2.1 Absolute Maximum Ratings

The Absolute Maximum Ratings define the stress limits beyond which permanent damage to the device may occur. These values are not for continuous operation. The key ratings are: a maximum reverse voltage (VR) of 5V, a continuous forward current (IF) of 30mA, and a peak forward current (IFP) of 40mA permissible only under pulsed conditions (duty cycle 1/10 at 1kHz). The maximum power dissipation (Pd) is 110mW. The device can withstand an Electrostatic Discharge (ESD) of 150V per the Human Body Model (HBM). The operating temperature range (Topr) is from -40°C to +85°C, and the storage temperature (Tstg) ranges from -40°C to +90°C. Soldering temperature limits are specified for two processes: reflow soldering at 260°C for 10 seconds and hand soldering at 350°C for a maximum of 3 seconds.

2.2 Electro-Optical Characteristics

The Electro-Optical Characteristics are measured at a standard test condition of Ta=25°C and an IF of 20mA. The luminous intensity (Iv) has a typical range from 360.0 mcd to 900.0 mcd, with a tolerance of ±11%. The viewing angle (2θ1/2) is 130 degrees, providing a wide beam of light. The forward voltage (VF) ranges from 2.70V to 3.70V. The reverse current (IR) is specified at a maximum of 50 μA when a reverse voltage (VR) of 5V is applied. It is crucial to note that the device is not designed for operation in reverse bias; the VR rating is for IR testing purposes only.

3. Binning System Explanation

To ensure consistency in production, LEDs are sorted into performance bins. This system allows designers to select components that meet specific minimum performance criteria for their application.

3.1 Luminous Intensity Binning

The luminous output is categorized into four bin codes (T2, U1, U2, V1) based on minimum and maximum intensity values measured at IF=20mA. For example, bin code T2 covers intensities from 360.0 mcd to 450.0 mcd, while bin code V1 covers the highest range from 715.0 mcd to 900.0 mcd. Designers must account for the ±11% tolerance within each bin.

3.2 Forward Voltage Binning

The forward voltage is binned into five codes (10, 11, 12, 13, 14), each representing a 0.2V range. Code 10 spans 2.70V to 2.90V, and code 14 spans 3.50V to 3.70V. A tolerance of ±0.1V applies. Selecting LEDs from a specific voltage bin can help in designing more consistent current-limiting circuits, especially in parallel LED arrays.

3.3 Chromaticity Coordinate Binning

The color consistency of the Pure White light is controlled through chromaticity coordinate binning on the CIE 1931 diagram. The datasheet defines four bin codes (1, 2, 3, 4), each as a quadrilateral area on the (x, y) coordinate plane. For instance, Bin 1 is bounded by the points (0.274, 0.226), (0.274, 0.258), (0.294, 0.286), and (0.294, 0.254). The tolerance for these coordinates is ±0.01. This ensures the emitted white light falls within a predictable and narrow color range.

4. Performance Curve Analysis

While the PDF references typical electro-optical characteristic curves and a CIE Chromaticity Diagram on specific pages, the exact graphical data (e.g., IV curves, relative intensity vs. current, intensity vs. temperature) is not provided in the text content. In a complete datasheet, these curves are critical for understanding device behavior under non-standard conditions. Designers typically use such curves to extrapolate performance at different drive currents or ambient temperatures, to understand the spectral power distribution, and to visualize the color point on the chromaticity diagram relative to the defined bins and the Planckian locus.

5. Mechanical and Package Information

5.1 Package Dimensions

The LED has a compact SMD (Surface Mount Device) package. The dimensional drawing indicates key measurements including length, width, and height, with a standard tolerance of ±0.1mm unless otherwise noted. The specific dimensions define the footprint required on the PCB and the clearance needed above the board.

5.2 Polarity Identification and Pad Design

The package includes markings or structural features (like a chamfered corner or a dot) to indicate the cathode (negative) terminal, which is essential for correct orientation during assembly. The recommended land pattern (pad layout) on the PCB is typically provided to ensure proper soldering and mechanical stability.

6. Soldering and Assembly Guidelines

Proper handling and soldering are critical to maintaining LED performance and reliability.

6.1 Reflow Soldering Parameters

The device is rated for Pb-free reflow soldering with a peak temperature of 260°C for 10 seconds. A recommended temperature profile should be followed to gradually heat and cool the device, minimizing thermal shock. Reflow soldering should not be performed more than two times on the same device.

6.2 Storage and Moisture Sensitivity

The LEDs are packaged in moisture-resistant barrier bags with desiccant. The bag must not be opened until the components are ready for use. After opening, unused LEDs should be stored at ≤30°C and ≤60% Relative Humidity (RH) and used within 168 hours (7 days). If this window is exceeded or if the desiccant indicator shows saturation, a baking treatment at 60 ±5°C for 24 hours is required before use to remove absorbed moisture and prevent "popcorning" during reflow.

6.3 Hand Soldering and Repair Precautions

If hand soldering is necessary, the iron tip temperature must be below 350°C, and contact time per terminal should not exceed 3 seconds. A low-power iron (≤25W) is recommended. A cooling interval of at least 2 seconds should be observed between soldering each terminal. Repair after initial soldering is strongly discouraged. If unavoidable, a specialized double-head soldering iron should be used to simultaneously heat both terminals, preventing mechanical stress on the LED die. The potential for characteristic degradation due to repair must be evaluated beforehand.

7. Packaging and Ordering Information

7.1 Reel and Tape Specifications

The components are supplied on 7-inch diameter reels with 8mm wide carrier tape. Each reel contains 3000 pieces. Detailed reel dimensions and carrier tape pocket dimensions are provided to ensure compatibility with automated assembly equipment feeders.

7.2 Label Explanation

The packaging label contains several codes: CPN (Customer's Product Number), P/N (Product Number), QTY (Packing Quantity), CAT (Luminous Intensity Rank/Bin), HUE (Chromaticity Coordinates & Dominant Wavelength Rank), REF (Forward Voltage Rank/Bin), and LOT No (Lot Number for traceability).

8. Application Suggestions and Design Considerations

8.1 Current Limiting and Protection

LEDs are current-driven devices. An external current-limiting resistor is mandatory in series with the LED to prevent thermal runaway and burnout. Even a small increase in forward voltage can cause a large, potentially destructive increase in current. The resistor value should be calculated based on the supply voltage, the LED's forward voltage (using the maximum value from the bin or datasheet for safety), and the desired forward current (not exceeding 30mA continuous).

8.2 Thermal Management

Although the power dissipation is low (110mW max), effective thermal management on the PCB is important for maintaining long-term reliability and stable light output, especially when operating at high ambient temperatures or at high drive currents. Ensuring adequate copper area around the LED pads helps dissipate heat.

8.3 ESD Protection

With an ESD rating of 150V (HBM), the device has moderate sensitivity. Standard ESD precautions should be observed during handling, assembly, and testing. This includes the use of grounded workstations, wrist straps, and conductive containers.

9. Technical Comparison and Differentiation

The 19-217 LED's key differentiators are its combination of a very small form factor, wide 130-degree viewing angle, and compliance with modern environmental standards (RoHS, REACH, Halogen-Free). Compared to larger through-hole LEDs, it enables significant space savings. The defined binning structure for intensity, voltage, and color provides designers with predictable performance, which is a critical advantage in applications requiring visual consistency, such as backlighting arrays or status indicators.

10. Frequently Asked Questions Based on Technical Parameters

10.1 What resistor value should I use with a 5V supply?

Using Ohm's Law (R = (Vsupply - Vf) / If) and assuming a worst-case Vf of 3.7V (from Bin 14) and a target If of 20mA, the calculation is R = (5V - 3.7V) / 0.020A = 65 Ohms. The nearest standard value (e.g., 68 Ohms) should be chosen, and the resistor's power rating (P = I^2 * R) should be checked.

10.2 Can I drive this LED without a current-limiting resistor if I use a constant voltage source equal to Vf?

No. This is strongly discouraged. The forward voltage has a range and varies with temperature. A constant voltage source set to a nominal Vf value does not regulate current. Minor variations could lead to excessive current, exceeding the Absolute Maximum Rating and causing immediate or gradual failure.

10.3 Why is the storage time after opening the bag limited to 7 days?

The plastic packaging of SMD components can absorb moisture from the air. During the high-temperature reflow soldering process, this trapped moisture can rapidly vaporize, creating internal pressure that may crack the package or delaminate internal layers—a phenomenon known as "popcorning." The 7-day limit is the calculated safe exposure time for this level of moisture sensitivity.

11. Practical Design and Usage Case

Consider designing a control panel with multiple white indicator LEDs. To ensure uniform brightness, specify LEDs from the same luminous intensity bin (e.g., all from U1: 450-565 mcd). To simplify the current-limiting circuit design for a common supply voltage, specify LEDs from the same or a narrow forward voltage bin. The wide 130-degree viewing angle ensures the indicators are visible from various angles without requiring secondary optics. The small package size allows them to be placed close to switches or labels. The Halogen-Free and RoHS compliance is essential for selling the final product in global markets.

12. Operating Principle Introduction

This LED is a semiconductor photonic device. Its core is a chip made of Indium Gallium Nitride (InGaN) materials. When a forward voltage exceeding the diode's threshold is applied, electrons and holes recombine in the active region of the semiconductor, releasing energy in the form of photons—light. The specific composition of the InGaN layers determines the wavelength of the emitted light. In this case, the emitted blue light from the chip is partially converted to longer wavelengths by the yellow phosphor contained within the surrounding diffused resin, resulting in the perception of "Pure White" light. The diffused resin also helps scatter the light, creating the wide viewing angle.

13. Technology Trends

The general trend in LED technology continues toward higher efficiency (more lumens per watt), improved color rendering, and greater miniaturization. For SMD indicator-type LEDs, there is a focus on achieving higher brightness in smaller packages, expanding color gamuts, and further improving reliability and thermal performance. Integration of driver circuitry or protection features within the LED package is also an area of development. Environmental compliance, as seen with this device's adherence to Halogen-Free standards, remains a critical driver in component selection across the electronics industry.