SMD LED 27-21 Brilliant Red Datasheet - Package Dimensions - Forward Voltage 1.75-2.35V - Luminous Intensity 45-112mcd - English Technical Document

1. Product Overview

The 27-21 SMD LED is a surface-mount device designed for high-density electronic assemblies. This component utilizes AlGaInP chip technology to produce a brilliant red emitted color with a water-clear resin encapsulation. Its primary advantage lies in its significantly reduced footprint compared to traditional lead-frame type LEDs, enabling more compact printed circuit board (PCB) designs, higher component packing density, and ultimately smaller end-user equipment. The lightweight construction further makes it suitable for miniature and portable applications where weight and space are critical constraints.

1.1 Core Features and Compliance

The device is supplied on 8mm tape wound onto 7-inch diameter reels, making it fully compatible with standard automated pick-and-place assembly equipment. It is designed for use with both infrared and vapor phase reflow soldering processes, which are common in high-volume electronics manufacturing. The product is a mono-color type, specifically brilliant red. It is manufactured as a Pb-free (lead-free) component, ensuring compliance with environmental regulations such as the EU's RoHS (Restriction of Hazardous Substances) directive. The product also complies with EU REACH regulations and meets halogen-free standards, with Bromine (Br) and Chlorine (Cl) content each below 900 ppm and their combined total below 1500 ppm.

2. Technical Specifications Deep Dive

This section provides a detailed analysis of the electrical, optical, and environmental limits and characteristics of the 27-21 SMD LED. All parameters are specified at an ambient temperature (Ta) of 25°C unless otherwise noted.

2.1 Absolute Maximum Ratings

The absolute maximum ratings define the stress limits beyond which permanent damage to the device may occur. These are not operating conditions. The maximum reverse voltage (VR) that can be applied is 5V. The continuous forward current (IF) must not exceed 25 mA. For pulsed operation, a peak forward current (IFP) of 60 mA is allowed under a duty cycle of 1/10 at 1 kHz. The maximum power dissipation (Pd) is 60 mW. The device can withstand an electrostatic discharge (ESD) of 2000V per the Human Body Model (HBM). The operating temperature range (Topr) is from -40°C to +85°C, and the storage temperature range (Tstg) is from -40°C to +90°C. For soldering, the maximum reflow temperature is 260°C for 10 seconds, while hand soldering should be limited to 350°C for 3 seconds per terminal.

2.2 Electro-Optical Characteristics

The typical performance parameters under normal operating conditions are listed here. With a forward current (IF) of 20 mA, the luminous intensity (Iv) ranges from a minimum of 45.0 mcd to a maximum of 112.0 mcd. The viewing angle (2θ1/2), defined as the full angle at half intensity, is typically 130 degrees, indicating a wide viewing pattern. The peak wavelength (λp) is typically 632 nm, and the dominant wavelength (λd) ranges from 617.5 nm to 633.5 nm, defining the perceived color. The spectral bandwidth (Δλ) is typically 20 nm. The forward voltage (VF) at 20 mA ranges from 1.75V to 2.35V. The reverse current (IR) is a maximum of 10 μA when a reverse voltage of 5V is applied.

3. Binning System Explanation

To ensure consistency in production and application, LEDs are sorted into bins based on key performance parameters. This allows designers to select components that meet specific tolerance requirements for their application.

3.1 Luminous Intensity Binning

Luminous intensity is categorized into four bin codes (P1, P2, Q1, Q2) measured at IF=20mA. P1 covers 45.0 to 57.0 mcd, P2 from 57.0 to 72.0 mcd, Q1 from 72.0 to 90.0 mcd, and Q2 from 90.0 to 112.0 mcd. The tolerance for luminous intensity is ±11%.

3.2 Dominant Wavelength Binning

Dominant wavelength, which correlates with color, is binned into four codes (E4, E5, E6, E7). E4 ranges from 617.5 to 621.5 nm, E5 from 621.5 to 625.5 nm, E6 from 625.5 to 629.5 nm, and E7 from 629.5 to 633.5 nm. The tolerance is ±1 nm.

3.3 Forward Voltage Binning

Forward voltage is binned into three codes (0, 1, 2). Bin 0 covers 1.75V to 1.95V, Bin 1 from 1.95V to 2.15V, and Bin 2 from 2.15V to 2.35V, all measured at IF=20mA. The tolerance is ±0.1V.

4. Performance Curve Analysis

While specific graphical data is referenced in the datasheet, typical performance curves for such an LED would illustrate the relationship between forward current and luminous intensity, forward voltage versus temperature, and the spectral power distribution. These curves are essential for understanding device behavior under non-standard conditions, such as different drive currents or ambient temperatures. Designers use these to predict brightness output, power consumption, and color shift over the operating range.

5. Mechanical and Package Information

5.1 Package Dimensions

The 27-21 SMD LED has a compact surface-mount package. The dimensional drawing provides critical measurements including overall length, width, and height, as well as the placement and size of the solder pads. The cathode is typically identified by a marking or a chamfered corner on the package. All dimensions have a standard tolerance of ±0.1 mm unless otherwise specified on the drawing. Precise adherence to these dimensions is crucial for successful PCB footprint design and automated assembly.

6. Soldering and Assembly Guidelines

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

6.1 Storage and Moisture Sensitivity

The LEDs are packaged in moisture-resistant bags with desiccant. The unopened bag should be stored at 30°C or less and 90% relative humidity (RH) or less. Once opened, the components have a floor life of 1 year under conditions of 30°C/60% RH or less. Unused parts should be resealed in a moisture-proof package. If the desiccant indicator shows moisture absorption or the storage time is exceeded, a baking treatment at 60 ±5°C for 24 hours is required before reflow soldering.

6.2 Reflow Soldering Profile

For Pb-free soldering, a specific temperature profile must be followed: pre-heating between 150-200°C for 60-120 seconds, a time above liquidus (217°C) of 60-150 seconds, a peak temperature not exceeding 260°C held for a maximum of 10 seconds, and controlled ramp-up and cool-down rates (max 6°C/sec and 3°C/sec, respectively). Reflow soldering should not be performed more than twice on the same component.

6.3 Hand Soldering and Repair

If hand soldering is necessary, the soldering iron tip temperature must be below 350°C, applied for no more than 3 seconds per terminal. The iron should have a capacity of less than 25W, and a minimum interval of 2 seconds should be left between soldering each terminal. Repair after initial soldering is strongly discouraged. If absolutely unavoidable, a dual-head soldering iron must be used to simultaneously heat both terminals and avoid mechanical stress. The potential for damage must be assessed beforehand.

7. Packaging and Ordering Information

The product is supplied in carrier tape on reels. Each reel contains 3000 pieces. The packaging includes a moisture-proof aluminum bag with a desiccant and a label. The label contains key information: Customer's Product Number (CPN), Product Number (P/N), Packing Quantity (QTY), Luminous Intensity Rank (CAT), Chromaticity Coordinates & Dominant Wavelength Rank (HUE), Forward Voltage Rank (REF), and Lot Number (LOT No). Detailed drawings for the reel and carrier tape dimensions are provided, with standard tolerances of ±0.1 mm.

8. Application Suggestions and Design Considerations

8.1 Typical Application Scenarios

The 27-21 SMD LED is well-suited for backlighting applications in automotive dashboards and switches. In telecommunications, it can serve as an indicator or backlight in telephones and fax machines. It is also applicable for flat backlighting behind LCDs, switches, and symbols, as well as for general indicator use.

8.2 Critical Design Considerations

Current Limiting: An external current-limiting resistor is mandatory. LEDs are current-driven devices, and a small change in forward voltage can cause a large change in current, potentially leading to immediate burnout. The resistor value must be calculated based on the supply voltage, the LED's forward voltage (using the maximum value from the datasheet for safety), and the desired operating current (not exceeding 25 mA continuous).



Thermal Management: Although power dissipation is low, ensuring adequate PCB copper area or thermal vias can help maintain lower junction temperatures, especially in high ambient temperature environments, which promotes longer lifespan and stable light output.



ESD Protection: While the device has a 2000V HBM rating, implementing basic ESD protection on sensitive lines in the circuit is considered good design practice, particularly during handling and assembly.

9. Application Restrictions and Disclaimer

This product is intended for general electronics applications. It is not designed or qualified for high-reliability applications where failure could lead to personal injury, significant property damage, or environmental harm. This includes, but is not limited to, military and aerospace systems, automotive safety and security systems (e.g., airbags, braking), and life-supporting medical equipment. For such applications, components with different specifications, qualifications, and reliability assurances are required. The performance guarantees outlined in this datasheet apply only when the device is operated within the specified absolute maximum ratings and recommended operating conditions. The manufacturer reserves the right to adjust product materials. The warranty period for the product is twelve (12) months from the date of shipment. Graphs and typical values are for reference only and do not represent guaranteed minimum or maximum performance limits.