IR29-01C/L510/R/TR8 LED Datasheet - 1.2mm Round SMD - 1.6V Forward Voltage - 940nm Infrared - 100mW Power - English Technical Document

1. Product Overview

The IR29-01C/L510/R/TR8 is a subminiature, side-looking infrared (IR) emitting diode designed for surface-mount applications. It features a compact double-ended package molded in water-clear plastic with a spherical top lens, optimized for efficient infrared emission. The device's spectral output is specifically matched to silicon photodiodes and phototransistors, making it an ideal source for IR sensing systems. Its primary advantages include a small form factor, low forward voltage, and compliance with modern environmental standards such as RoHS, REACH, and halogen-free requirements.

1.1 Core Features and Target Market

Key features of this component include its miniature SMD package, which facilitates high-density PCB designs. The low forward voltage contributes to energy-efficient operation. It is supplied on 8mm tape wound on a 7-inch diameter reel, compatible with automated pick-and-place assembly processes. The device is lead-free (Pb-free) and complies with stringent environmental regulations, including limits on bromine (Br) and chlorine (Cl) content. This IR LED is primarily targeted at designers and engineers developing infrared-based systems such as proximity sensors, object detection, encoders, and data transmission modules where reliable, matched IR emission is critical.

2. Technical Parameters: In-Depth Objective Interpretation

This section provides a detailed analysis of the device's electrical, optical, and thermal characteristics as defined in the datasheet.

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.

• Continuous Forward Current (IF): 50 mA. This is the maximum DC current that can be applied continuously to the LED.
• Peak Forward Current (IFP): 500 mA. This high current is permissible only under pulsed conditions with a pulse width ≤ 100 μs and a duty cycle ≤ 1%. This rating is useful for applications requiring brief, high-intensity pulses.
• Reverse Voltage (VR): 5 V. Exceeding this reverse bias voltage can cause junction breakdown.
• Operating & Storage Temperature (Topr, Tstg): -40°C to +100°C. This wide range ensures reliability in harsh environments.
• Soldering Temperature (Tsol): 260°C for a maximum of 5 seconds, defining the reflow soldering profile.
• Power Dissipation (Pc): 100 mW at or below 25°C ambient temperature. This parameter is crucial for thermal management design.

2.2 Electro-Optical Characteristics

The Electro-Optical Characteristics (Typical at Ta=25°C) define the expected performance under normal operating conditions.

• Radiant Intensity (IE): Typically 25 mW/sr at IF=20mA, and 100 mW/sr at IF=70mA (pulsed). Radiant intensity measures the optical power emitted per unit solid angle, indicating the brightness of the IR source.
• Peak Wavelength (λp): 940 nm. This is the wavelength at which the emitted optical power is maximum, perfectly matched to the peak sensitivity of common silicon photodetectors.
• Spectral Bandwidth (Δλ): Typically 30 nm. This defines the range of wavelengths emitted, centered around the peak wavelength.
• Forward Voltage (VF): Typically 1.30V, with a maximum of 1.60V at IF=20mA. At IF=70mA (pulsed), it is typically 1.50V with a maximum of 2.00V. This low VF is beneficial for low-voltage circuit designs.
• Reverse Current (IR): Maximum 10 μA at VR=5V, indicating good junction quality.
• View Angle (2θ1/2): 15 degrees. This narrow viewing angle indicates a focused beam, which is characteristic of side-looking LEDs with a lens, useful for directed IR applications.

3. Performance Curve Analysis

The datasheet includes several characteristic curves that provide deeper insight into device behavior under varying conditions.

3.1 Forward Current vs. Ambient Temperature

This graph shows the derating of the maximum allowable forward current as the ambient temperature increases. To prevent overheating and ensure long-term reliability, the forward current must be reduced when operating above 25°C. The curve typically shows a linear decrease from the rated current at 25°C to zero at the maximum junction temperature.

3.2 Radiant Intensity vs. Forward Current

This plot illustrates the relationship between the drive current (IF) and the optical output power (Radiant Intensity). It is generally linear in the normal operating range, confirming that optical output is directly proportional to current. However, at very high currents, efficiency may drop due to thermal effects.

3.3 Forward Current vs. Forward Voltage

This IV curve depicts the exponential relationship typical of a diode. The "knee" voltage is around the typical VF value. Understanding this curve is essential for designing the current-limiting driver circuit.

3.4 Spectral Distribution

This graph displays the relative radiant power as a function of wavelength, centered at 940 nm with a defined bandwidth. It visually confirms the spectral matching to silicon detectors, which have peak sensitivity in the 800-1000 nm range.

3.5 Relative Radiant Intensity vs. Angular Displacement

This polar plot defines the radiation pattern or beam profile of the LED. The 15-degree viewing angle (full width at half maximum, FWHM) is confirmed here. The side-looking design with a lens creates this directional emission pattern, which is critical for aligning the LED with a detector in a sensor assembly.

4. Mechanical and Package Information

4.1 Package Dimensions

The device is a 1.2mm round subminiature SMD package. The detailed dimensional drawing specifies all critical measurements including body diameter, height, lead spacing, and pad dimensions. Key tolerances are typically ±0.1mm unless otherwise noted. Precise dimensions are vital for PCB footprint design and ensuring proper placement during assembly.

4.2 Polarity Identification

The cathode is typically indicated by a visual marker on the package, such as a notch, a flat edge, or a green marking. The datasheet's dimensional drawing should clearly show this identification feature to prevent reverse mounting during assembly.

4.3 Carrier Tape and Reel Dimensions

The product is supplied in an 8mm wide embossed carrier tape on a 7-inch diameter reel. The datasheet provides detailed drawings of the pocket dimensions, pitch, and reel specifications. This packaging supports automated high-speed assembly equipment. The standard reel contains 1500 pieces.

5. Soldering and Assembly Guidelines

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

5.1 Reflow Soldering Profile

A lead-free (Pb-free) reflow soldering temperature profile is recommended. The peak temperature should not exceed 260°C, and the time above 240°C should be limited (typically to 5 seconds as per the absolute maximum rating). The preheat, soak, reflow, and cooling stages must be controlled to minimize thermal shock. Reflow soldering should not be performed more than two times.

5.2 Hand Soldering

If hand soldering is necessary, extreme care must be taken. The soldering iron tip temperature should be below 350°C, and contact time with each terminal should be limited to 3 seconds or less. A low-power iron (≤25W) is recommended. Allow sufficient cooling time between soldering each lead to prevent heat damage to the plastic package.

5.3 Storage and Moisture Sensitivity

The LEDs are packaged in a moisture-proof bag with desiccant. Key precautions include:

• Do not open the bag until ready for use.
• Store unopened bags at ≤30°C and ≤60% RH.
• Use within one year of shipment.
• After opening, use components within 168 hours (7 days) under the same storage conditions.
• If the storage time is exceeded or the desiccant indicates moisture, a baking treatment at 60±5°C for at least 24 hours is required before soldering to prevent "popcorn" effect during reflow.

6. Packaging and Ordering Information

6.1 Packing Procedure

The components are packed in an aluminum laminated moisture-proof bag containing desiccant. The bag is labeled with critical information including the part number (P/N), quantity (QTY), lot number (LOT No.), and other relevant codes like peak wavelength (HUE).

6.2 Device Selection Guide

The specific device, IR29-01C/L510/R/TR8, uses a Gallium Aluminum Arsenide (GaAlAs) chip material and a water-clear lens. The part number itself likely encodes key attributes: IR for Infrared, 29 may refer to a series or size, 01C could be a variant code, L510 might indicate the peak wavelength bin, R for reel packaging, and TR8 for 8mm tape.

7. Application Suggestions

7.1 Typical Application Scenarios

This IR LED is suitable for a wide range of infrared sensing and transmission applications, including:

• Proximity and Presence Sensing: Used in automatic faucets, soap dispensers, hand dryers, and touchless switches.
• Object Detection and Counting: In vending machines, industrial automation, and conveyor belt systems.
• Optical Encoders: For position and speed sensing in motors and rotating equipment.
• IR Data Transmission: In remote control units and short-range data links (requires appropriate modulation).
• Security Systems: As an invisible light source for night-vision cameras and beam-break sensors.

7.2 Design Considerations and Circuit Protection

Current Limiting is Mandatory: As explicitly warned in the datasheet, an external current-limiting resistor must always be used in series with the LED. The forward voltage has a negative temperature coefficient (decreases as temperature rises). Without a resistor, a small increase in supply voltage or a decrease in VF due to heating can cause a large, uncontrolled increase in current, leading to immediate thermal runaway and device failure.

Driver Circuit Design: For DC operation, a simple series resistor calculated using Ohm's Law (R = (Vcc - VF) / IF) is sufficient. For pulsed operation to achieve higher peak intensity, a transistor or MOSFET switch driven by a pulse generator can be used. Ensure the pulse width and duty cycle stay within the specified limits (≤100μs, ≤1%).

Optical Alignment: The 15-degree narrow beam requires careful mechanical alignment with the receiving photodetector to maximize signal strength. Consider the radiation pattern graph when designing the sensor housing.

8. Technical Comparison and Differentiation

Compared to standard top-emitting IR LEDs, the side-looking (or side-view) package of the IR29-01C offers a distinct advantage in applications where the PCB must be mounted parallel to the sensing plane. This eliminates the need for light pipes or additional optics to redirect the beam by 90 degrees, simplifying mechanical design and reducing component count. Its 940nm wavelength provides a good balance between silicon detector sensitivity and lower visibility compared to 850nm sources, making it less noticeable in operation. The miniature 1.2mm size allows for very compact sensor designs.

9. Frequently Asked Questions (Based on Technical Parameters)

Q1: Why is a current-limiting resistor absolutely necessary?
A1: The LED's I-V characteristic is exponential. A slight change in forward voltage (which itself decreases with temperature) can cause a large change in current. Without a series resistor to stabilize the current, thermal runaway occurs, rapidly destroying the LED.

Q2: Can I drive this LED directly from a 3.3V or 5V microcontroller pin?
A2: No. Microcontroller pins have limited current sourcing/sinking capability (often 20-40mA max) and are not designed for driving LEDs directly. Always use a driver circuit (e.g., a transistor) controlled by the MCU pin, with a current-limiting resistor in series with the LED.

Q3: What is the difference between Radiant Intensity (mW/sr) and Luminous Intensity (mcd)?
A3: Luminous Intensity (measured in candela) is weighted by the human eye's sensitivity (photopic curve), which is nearly zero in the infrared spectrum. Radiant Intensity measures actual optical power emitted per solid angle, making it the correct metric for IR devices intended for machine, not human, detection.

Q4: How do I interpret the 15-degree viewing angle?
A4: This is the Full Width at Half Maximum (FWHM) angle. The radiant intensity is highest at 0 degrees (straight out from the side of the package) and drops to 50% of its maximum value at ±7.5 degrees from the centerline, making the total beam width 15 degrees.

10. Practical Design and Usage Case

Case: Designing a Paper Towel Dispenser Sensor. The IR29-01C is an ideal candidate. It would be mounted on the edge of a PCB facing sideways across the dispensing slot. A matching silicon phototransistor would be placed on the opposite side. Under normal conditions, the IR beam is detected. When a hand interrupts the beam, the microcontroller triggers the motor to dispense a towel. The side-looking package allows the PCB to be mounted vertically behind the front panel, with the LED and detector peeking through small holes, creating a very sleek design. The 940nm wavelength is invisible, so no distracting red glow is present. The designer must calculate the appropriate series resistor for a 20mA drive current from a 5V system rail (R ≈ (5V - 1.3V) / 0.02A = 185Ω, a 180Ω or 200Ω standard value would be suitable).

11. Principle Introduction

An Infrared Light Emitting Diode (IR LED) is a semiconductor p-n junction diode that emits non-visible infrared light when electrically biased in the forward direction. Electrons recombine with holes within the device, releasing energy in the form of photons. The wavelength of the emitted light is determined by the energy bandgap of the semiconductor material. For the IR29-01C, the Gallium Aluminum Arsenide (GaAlAs) material system is used to produce photons with a peak energy corresponding to a 940nm wavelength. The water-clear epoxy package acts as a lens, shaping the emitted light into a focused beam. The side-view construction is achieved by mounting the semiconductor chip on its side within the package, causing light to be emitted parallel to the PCB plane.

12. Development Trends

The trend in subminiature IR LEDs like the IR29-01C is towards even smaller package sizes (e.g., chip-scale packages), higher radiant intensity and efficiency, and broader operating temperature ranges to support automotive and industrial applications. Integration is another key trend, with devices combining the IR emitter, driver, and sometimes a photodetector into a single module. There is also a focus on improving the speed (modulation capability) for data communication applications like IR Data Association (IrDA) and consumer electronics remote controls. Furthermore, development continues to enhance reliability and robustness against electrostatic discharge (ESD) and harsh environmental conditions.