SMD LED 19-21/T1D-CPQTY/3T Datasheet - 1.9x2.1mm - 3.0V Max - 40mW - Pure White - English Technical Document

1. Product Overview

The 19-21 SMD LED is a compact, surface-mount device designed for modern electronic applications requiring reliable indicator or backlighting functionality. Its primary advantage lies in its significantly reduced footprint compared to traditional lead-frame LEDs, enabling higher packing density on PCBs, reduced storage space, and ultimately contributing to the miniaturization of end equipment. The lightweight construction further makes it ideal for portable and space-constrained applications.

This LED is a mono-color type, emitting a pure white light, and is constructed with a yellow diffused resin. It is fully compliant with contemporary environmental and manufacturing standards, being Pb-free, RoHS compliant, EU REACH compliant, and halogen-free (Br <900 ppm, Cl <900 ppm, Br+Cl < 1500 ppm). The product is supplied in 8mm tape on 7-inch diameter reels, making it fully compatible with automated pick-and-place assembly equipment and standard infrared or vapor phase reflow soldering processes.

2. Technical Parameters: In-Depth Objective Interpretation

2.1 Absolute Maximum Ratings

These ratings define the stress limits beyond which permanent damage to the device may occur. Operation at or beyond these limits is not advised.

• Reverse Voltage (VR): 5V. Exceeding this voltage in reverse bias can cause junction breakdown.
• Forward Current (IF): 10mA. The maximum continuous DC current recommended for reliable operation.
• Peak Forward Current (IFP): 40mA at a duty cycle of 1/10 and 1kHz. This rating allows for brief pulses of higher current, useful in multiplexing schemes, but average power dissipation must be managed.
• Power Dissipation (Pd): 40mW. The maximum power the package can dissipate at Ta=25°C, calculated as VF * IF.
• Electrostatic Discharge (ESD) HBM: 150V. This Human Body Model rating indicates a moderate level of ESD sensitivity; proper handling procedures are essential.
• Operating & Storage Temperature: -40°C to +85°C (operating) and -40°C to +90°C (storage). This wide range ensures functionality in harsh environments.
• Soldering Temperature: Reflow profile peak at 260°C for max 10 seconds; hand soldering at 350°C for max 3 seconds per terminal.

2.2 Electro-Optical Characteristics

These parameters are measured at a standard test condition of Ta=25°C and IF=5mA, providing the baseline performance.

• Luminous Intensity (Iv): Ranges from a minimum of 45.0 mcd to a maximum of 112.0 mcd, with a typical value provided. A tolerance of ±11% applies.
• Viewing Angle (2θ1/2): A typical wide viewing angle of 110 degrees, characteristic of a diffused LED package.
• Forward Voltage (VF): Ranges from 2.60V to 3.00V at IF=5mA, with a tolerance of ±0.05V. This parameter is critical for current-limiting resistor calculation.
• Reverse Current (IR): Maximum of 50 µA at VR=5V. The device is not designed for operation in reverse bias; this test is for leakage characterization only.

3. Binning System Explanation

To ensure color and brightness consistency in production, LEDs are sorted into bins.

3.1 Luminous Intensity Binning

Two bins are defined based on minimum luminous intensity at IF=5mA:

• Bin Code P: 45 mcd (Min) to 72 mcd (Max).
• Bin Code Q: 72 mcd (Min) to 112 mcd (Max).

3.2 Forward Voltage Binning

Four bins are defined for forward voltage at IF=5mA:

• Bin Code 28: 2.6V to 2.7V
• Bin Code 29: 2.7V to 2.8V
• Bin Code 30: 2.8V to 2.9V
• Bin Code 31: 2.9V to 3.0V

3.3 Chromaticity Coordinates Binning

The white color point is controlled within specific regions on the CIE 1931 chromaticity diagram, defined by four quadrilateral bins (Codes 1-4) with a tolerance of ±0.01. The provided coordinates define the corners of each bin, ensuring the emitted white light falls within a predictable color space.

4. Performance Curve Analysis

Typical characteristic curves provide insight into device behavior under varying conditions.

• Relative Luminous Intensity vs. Forward Current: Shows the non-linear relationship between drive current and light output. Intensity increases with current but may saturate at higher levels.
• Relative Luminous Intensity vs. Ambient Temperature: Demonstrates the negative temperature coefficient of light output. Luminous intensity typically decreases as the junction temperature rises.
• Forward Current vs. Forward Voltage (IV Curve): Illustrates the exponential relationship, crucial for understanding the dynamic resistance and the need for current regulation.
• Forward Current Derating Curve: Specifies the maximum allowable forward current as a function of ambient temperature to ensure the power dissipation rating (Pd) is not exceeded.
• Spectrum Distribution: Depicts the spectral power distribution of the white light, typically showing a blue LED peak combined with a broader yellow phosphor emission.
• Radiation Diagram: A polar plot visualizing the spatial distribution of light intensity, confirming the 110-degree viewing angle.

5. Mechanical and Package Information

5.1 Package Dimensions

The LED has a compact SMD package with nominal dimensions. The cathode is identified by a specific mark on the package body. All unspecified tolerances are ±0.1mm. The exact length, width, and height are defined in the dimensioned drawing.

5.2 Polarity Identification

Clear cathode marking is provided on the package to ensure correct orientation during PCB assembly. Incorrect polarity will prevent the LED from illuminating and may subject it to reverse voltage stress.

6. Soldering and Assembly Guidelines

6.1 Soldering Conditions

A Pb-free reflow soldering profile is recommended: pre-heating between 150-200°C for 60-120s, time above 217°C (liquidus) for 60-150s, with a peak temperature not exceeding 260°C for a maximum of 10 seconds. The maximum ramp-up rate is 6°C/sec and cool-down rate is 3°C/sec. Reflow soldering should not be performed more than two times. Avoid mechanical stress on the LED during heating and do not warp the PCB after soldering.

6.2 Storage and Handling Precautions

The LEDs are moisture-sensitive (MSL). Key precautions include:

• Storage: Do not open the moisture-proof bag until ready for use. Store unopened bags in a cool, dry place.
• Floor Life: After opening, use within 168 hours (7 days) if stored at ≤30°C and ≤60% RH. Otherwise, rebake at 60±5°C for 24 hours and repackage.
• ESD Protection: The device has an ESD HBM rating of 150V, necessitating the use of ESD-safe workstations and handling procedures.
• Current Limiting: An external current-limiting resistor is mandatory. The LED's exponential IV characteristic means a small voltage change causes a large current change, which can lead to immediate burnout without proper current regulation.

7. Packaging and Ordering Information

7.1 Packaging Specifications

The product is supplied in moisture-resistant packaging consisting of:

• Carrier Tape: 8mm width, loaded into...
• Reel: 7-inch diameter. Standard loaded quantity is 3000 pieces per reel.
• Moisture-Proof Bag: Aluminum bag containing the reel, along with a desiccant and humidity indicator card.

Detailed dimensions for the reel and carrier tape are provided with a standard tolerance of ±0.1mm unless otherwise noted.

7.2 Label Explanation

The packaging label includes codes for traceability and specification:

• CPN (Customer's Product Number)
• P/N (Product Number)
• QTY (Packing Quantity)
• CAT (Luminous Intensity Rank, e.g., P or Q)
• HUE (Chromaticity Coordinates & Dominant Wavelength Rank, e.g., 1-4)
• REF (Forward Voltage Rank, e.g., 28-31)
• LOT No (Lot Number for traceability)

8. Application Suggestions

8.1 Typical Application Scenarios

• Backlighting: Ideal for dashboard indicators, switch illumination, and flat backlighting for LCDs and symbols.
• Telecommunication Equipment: Status indicators and keypad backlighting in phones and fax machines.
• General Indication: Any application requiring a compact, reliable, white light source.

8.2 Design Considerations

• Current Drive: Always use a series resistor or constant current driver. Calculate the resistor value using R = (Vsupply - VF) / IF, where VF should be chosen from the maximum bin value (e.g., 3.0V) for a safe design.
• Thermal Management: While the power is low, ensure adequate PCB copper area or thermal vias if operating at high ambient temperatures or near maximum current, as per the derating curve.
• Optical Design: The 110-degree viewing angle and diffused resin provide a wide, soft emission pattern suitable for direct viewing or light guides.

9. Technical Comparison and Differentiation

The primary differentiation of the 19-21 LED lies in its balance of size, performance, and reliability. Compared to larger SMD LEDs (e.g., 3528), it offers significant space savings. Compared to smaller chip-scale packages, it is easier to handle and solder using standard SMT processes. Its specific binning structure for intensity, voltage, and chromaticity allows for tighter system design and better consistency in mass production compared to unbinned or loosely binned alternatives.

10. Frequently Asked Questions (Based on Technical Parameters)

10.1 Why is a current-limiting resistor mandatory?

The LED's forward voltage has a negative temperature coefficient and production variance (bins 28-31). A fixed voltage supply connected directly would cause uncontrolled current flow, quickly exceeding the absolute maximum rating of 10mA and destroying the device. The series resistor provides a simple, linear method of current regulation.

10.2 Can I drive this LED with a 5V supply?

Yes, but a series resistor is essential. For example, targeting IF=5mA with a worst-case VF of 3.0V: R = (5V - 3.0V) / 0.005A = 400 Ohms. A standard 390 or 430 Ohm resistor would be suitable. Always verify the actual current under operating conditions.

10.3 What does the 168-hour floor life mean?

This is the maximum time the LED can be exposed to ambient factory conditions (≤30°C/60% RH) after the moisture-proof bag is opened before moisture absorption might cause damage (\"popcorning\") during reflow soldering. If this time is exceeded, a 24-hour bake at 60°C is required to remove moisture.

11. Practical Design and Usage Case

Case: Designing a status indicator panel with uniform brightness. To ensure visual consistency across multiple LEDs on a panel, specify tighter binning requirements when ordering. For example, request all LEDs from Bin Q (higher intensity) and Bin 29 (VF 2.7-2.8V). Using a constant current driver set to 5mA instead of a voltage supply + resistors will further minimize brightness variations caused by small differences in forward voltage across the batch, resulting in a perfectly uniform appearance.

12. Operating Principle Introduction

This is a phosphor-converted white LED. The core is a semiconductor chip, typically made of Indium Gallium Nitride (InGaN), which emits blue light when forward biased (electrons and holes recombine in the PN junction). This blue light excites a yellow phosphor coating (Yttrium Aluminum Garnet, YAG:Ce) within the package. The combination of the remaining blue light and the broad-spectrum yellow emission from the phosphor results in the perception of white light by the human eye. The yellow diffused resin helps scatter the light, creating the wide viewing angle.

13. Technology Trends

The trend in SMD indicator LEDs continues toward higher efficiency (more lumens per watt), improved color rendering index (CRI) for white LEDs, and even smaller package sizes while maintaining or improving thermal performance. There is also a focus on enhancing reliability and longevity under higher drive currents and operating temperatures. The standardization of binning and the provision of detailed technical data, as seen in this datasheet, reflect the industry's move towards more predictable and design-friendly components for automated, high-volume manufacturing.