5mm Infrared LED HIR323C Datasheet - 5mm Diameter - 1.45V Forward Voltage - 850nm Wavelength - 150mW Power Dissipation - English Technical Document

1. Product Overview

The HIR323C is a high-intensity infrared emitting diode housed in a standard T-1 (5mm) package with a water-clear plastic lens. This device is engineered to deliver reliable performance in infrared sensing and communication systems. Its spectral output is specifically matched to be compatible with common silicon phototransistors, photodiodes, and infrared receiver modules, ensuring optimal system efficiency. The primary application domain for this component is within infrared-applied systems, which can include remote controls, object detection, proximity sensing, and optical switches.

1.1 Core Advantages and Target Market

The key advantages of this infrared LED stem from its design and material selection. It utilizes a GaAlAs (Gallium Aluminum Arsenide) chip material, which is known for efficient infrared emission. The package offers high radiant intensity, enabling strong signal transmission. A significant feature is its low forward voltage, which contributes to lower power consumption in the final application. The product is designed to comply with modern environmental and safety standards, being Pb-Free, RoHS compliant, EU REACH compliant, and Halogen-Free. This makes it suitable for a global market, particularly in consumer electronics, industrial automation, and security systems where reliable, long-life infrared sources are required.

2. Technical Parameter Deep Dive

This section provides a detailed, objective interpretation of the key technical parameters listed in the datasheet, explaining their significance for design engineers.

2.1 Absolute Maximum Ratings

These ratings define the stress limits beyond which permanent damage to the device may occur. Operation under these conditions is not guaranteed.

• Continuous Forward Current (IF): 100 mA. This is the maximum DC current that can be passed through the LED indefinitely under specified conditions.
• Peak Forward Current (IFP): 1.0 A. This high current is permissible only under pulsed conditions (pulse width ≤ 100μs, duty cycle ≤ 1%). It is useful for applications requiring very brief, high-intensity pulses.
• Reverse Voltage (VR): 5 V. Exceeding this voltage in the reverse bias direction can cause junction breakdown.
• Operating & Storage Temperature: Ranges from -40°C to +85°C (operating) and -40°C to +100°C (storage). This wide range ensures reliability in harsh environments.
• Power Dissipation (Pd): 150 mW at or below 25°C ambient temperature. This is the maximum power the package can dissipate as heat. The actual allowable forward current will derate at higher ambient temperatures.

2.2 Electro-Optical Characteristics

These parameters are measured under standard test conditions (Ta=25°C) and define the device's performance.

• Radiant Intensity (Ie): This is the optical power emitted per unit solid angle, measured in mW/sr. The typical value is 30 mW/sr at IF=20mA. Under pulsed operation at 100mA, it can reach 130 mW/sr. Higher radiant intensity translates to a longer operational range or better signal-to-noise ratio.
• Peak Wavelength (λp): 850 nm (typical). This is the wavelength at which the optical output power is maximum. 850nm is in the near-infrared spectrum, invisible to the human eye but efficiently detected by silicon-based sensors.
• Spectral Bandwidth (Δλ): 45 nm (typical). This defines the range of wavelengths emitted, centered around the peak wavelength. A narrower bandwidth can be beneficial for filtering out ambient light noise.
• Forward Voltage (VF): 1.45V (typical) at 20mA, with a maximum of 1.65V. At 100mA (pulsed), the maximum is 2.40V. The low VF is a key efficiency parameter.
• View Angle (2θ1/2): 15 degrees (typical). This is the full angle at which the radiant intensity drops to half of its maximum value (on-axis). A narrow view angle produces a more focused beam.

3. Binning System Explanation

The HIR323C employs a binning system to categorize devices based on their measured radiant intensity at the standard test current of 20mA. This allows designers to select parts that meet specific minimum output requirements for their application.

• Bin P: Radiant Intensity range from 15.0 mW/sr (min) to 24.0 mW/sr (max).
• Bin Q: Radiant Intensity range from 21.0 mW/sr (min) to 34.0 mW/sr (max).
• Bin R: Radiant Intensity range from 30.0 mW/sr (min) to 48.0 mW/sr (max).

Selection of a higher bin (e.g., R) guarantees a higher minimum output, which can be critical for ensuring consistent system performance, especially over temperature variations and product lifetime.

4. Performance Curve Analysis

The datasheet includes several graphs that illustrate the device's behavior under varying conditions. Understanding these is crucial for robust circuit design.

4.1 Forward Current vs. Ambient Temperature

This curve shows the derating of the maximum allowable continuous forward current as the ambient temperature increases. As temperature rises, the package's ability to dissipate heat decreases, so the current must be reduced to stay within the safe operating area (SOA) defined by the maximum power dissipation. Designers must use this graph to select appropriate current-limiting resistors or drivers for their expected operating environment.

4.2 Radiant Intensity vs. Forward Current

This graph depicts the relationship between the drive current (IF) and the optical output (Ie). It is generally non-linear. The output increases with current but may saturate at very high currents due to thermal and efficiency effects. The curve helps in determining the drive current needed to achieve a desired output level.

4.3 Spectral Distribution

This plot shows the relative radiant intensity as a function of wavelength. It confirms the peak wavelength (λp ~850nm) and the spectral bandwidth (Δλ). The shape of this curve is important for ensuring compatibility with the spectral sensitivity curve of the receiving sensor (phototransistor/photodiode).

4.4 Relative Radiant Intensity vs. Angular Displacement

This polar plot illustrates the emission pattern of the LED. The intensity is highest along the central axis (0°) and decreases as the angle increases. The 15-degree view angle is defined where the intensity falls to 50% of its peak. This information is vital for optical design, determining beam spread and alignment tolerances in a system.

5. Mechanical and Packaging Information

5.1 Package Dimension Drawing

The device conforms to the standard T-1 (5mm) round LED package outline. Key dimensions include the overall diameter (5.0mm typical), the lens height, and the lead spacing (2.54mm or 0.1 inches, which is a standard PCB hole spacing). The drawing specifies the anode and cathode leads, with the longer lead typically being the anode. All unspecified tolerances are ±0.25mm. Engineers must refer to this drawing for PCB footprint design and mechanical clearance checks.

5.2 Polarity Identification

The component uses the standard LED polarity convention: the longer lead is the Anode (+), and the shorter lead is the Cathode (-). The package may also have a flat side on the rim near the cathode lead. Correct polarity is essential for operation; reverse biasing beyond 5V can damage the device.

6. Soldering and Assembly Guidelines

Proper handling is critical to maintain device reliability and performance.

6.1 Lead Forming

• Bending must occur at least 3mm from the base of the epoxy bulb to avoid stress on the internal die and wire bonds.
• Forming should always be done before the soldering process.
• Mechanical stress on the package during forming must be minimized to prevent cracks or internal damage.
• PCB hole alignment must be precise to avoid mounting stress.

6.2 Storage Conditions

The recommended storage environment is at or below 30°C and 70% Relative Humidity (RH). The shelf life under these conditions is 3 months from shipment. For longer storage (up to one year), devices should be kept in a sealed container with a nitrogen atmosphere and desiccant to prevent moisture absorption, which can affect solderability and reliability.

6.3 Soldering Parameters

A minimum distance of 3mm must be maintained between the solder joint and the epoxy bulb to prevent thermal damage.

• Hand Soldering: Iron tip temperature maximum 300°C (for a 30W iron), soldering time maximum 3 seconds per lead.
• Wave/Dip Soldering: Preheat temperature maximum 100°C for up to 60 seconds. Solder bath temperature maximum 260°C, with immersion time not exceeding 5 seconds.

The datasheet provides a recommended soldering temperature profile, emphasizing the importance of controlled ramp-up, peak temperature, and cool-down rates to prevent thermal shock. Soldering (dip or hand) should not be performed more than once. After soldering, the device should be protected from vibration until it cools to room temperature.

6.4 Cleaning

If cleaning is necessary, only isopropyl alcohol at room temperature should be used, for a duration not exceeding one minute. Ultrasonic cleaning is strongly discouraged as the high-frequency vibrations can damage the internal structure of the LED. If absolutely required, the process must be carefully qualified beforehand.

7. Packaging and Ordering Information

7.1 Packing Specification

The devices are typically packed in anti-static bags to prevent damage from electrostatic discharge (ESD). A common packing configuration is: 200-500 pieces per bag, 5 bags placed in an inner carton, and 10 inner cartons placed in a master (outside) carton.

7.2 Label Form Specification

The label on the packaging contains critical information for traceability and correct application:

• P/N: Product Number (HIR323C).
• CAT: Luminous Intensity Rank (i.e., the bin code: P, Q, or R).
• LOT No: Lot Number for manufacturing traceability.
• Other codes may include customer part number (CPN), quantity (QTY), and date codes.

8. Application Suggestions

8.1 Typical Application Scenarios

• Infrared Remote Controls: For TVs, audio systems, and other consumer electronics.
• Object/Proximity Sensing: In appliances, vending machines, and industrial equipment to detect the presence or absence of an object.
• Optical Switches and Encoders: Where breaking or reflecting an infrared beam indicates position or movement.
• Security Systems: As part of infrared intrusion detection beams.
• Data Transmission: For short-range, simplex serial data links (IrDA compatible systems may require specific devices).

8.2 Design Considerations

• Current Limiting: An LED is a current-driven device. Always use a series resistor or constant current driver to set the forward current (IF) to the desired value, calculated from the supply voltage (Vcc), LED forward voltage (VF), and desired current: R = (Vcc - VF) / IF.
• Heat Management: For continuous operation at higher currents or in elevated ambient temperatures, consider the derating curve. Ensure adequate PCB copper area or other means to conduct heat away from the LED leads.
• Optical Alignment: The narrow 15-degree view angle requires careful mechanical alignment between the emitter and the detector for optimal signal strength.
• Ambient Light Immunity: For systems operating in environments with variable ambient light (e.g., sunlight), consider modulating the infrared signal at a specific frequency and using a receiver tuned to that frequency to reject background noise.

9. Technical Comparison and Differentiation

While many 5mm infrared LEDs exist, the HIR323C differentiates itself through a combination of parameters. Its high typical radiant intensity (30 mW/sr at 20mA) places it in the higher performance tier for its package size. The very low typical forward voltage (1.45V) enhances energy efficiency, which is particularly valuable in battery-powered applications. The specific matching to silicon photodetectors and compliance with stringent environmental standards (Halogen-Free, REACH) makes it a suitable choice for modern, eco-conscious designs requiring reliable, long-term performance.

10. Frequently Asked Questions (Based on Technical Parameters)

Q1: Can I drive this LED directly from a 3.3V or 5V microcontroller pin?
A: No. An LED must have its current limited. Connecting it directly to a low-impedance voltage source like a MCU pin would cause excessive current to flow, potentially destroying both the LED and the MCU output. Always use a current-limiting resistor or driver circuit.

Q2: What is the difference between the P, Q, and R bins?
A: They represent different guaranteed minimum levels of radiant output. Bin R has the highest minimum output (30 mW/sr), followed by Q (21 mW/sr), and then P (15 mW/sr). Choose based on the required signal strength and link margin in your application.

Q3: The datasheet shows a Peak Forward Current of 1A. Can I use this for high-power pulsed applications?
A: Yes, but only under the strict conditions noted: pulse width must be 100 microseconds or less, and the duty cycle must be 1% or less (e.g., one 100μs pulse every 10ms). This allows the LED to handle high instantaneous power without overheating.

Q4: Why is the storage condition and shelf life important?
A: Plastic-packaged electronic components can absorb moisture from the atmosphere. During the high-temperature soldering process, this trapped moisture can rapidly expand, causing internal delamination or \"popcorning,\" which cracks the package and destroys the device. Adhering to storage guidelines and baking components if necessary is critical for high-yield manufacturing.

11. Practical Design and Usage Case

Case: Designing a Simple Object Detection Sensor.
A common use is a break-beam sensor. The HIR323C is placed on one side of a path, and a phototransistor (matched to 850nm) is placed directly opposite. A microcontroller drives the LED through a 100Ω resistor from a 5V supply, resulting in a forward current of approximately (5V - 1.45V)/100Ω = 35.5mA. The LED is pulsed at 1kHz with a 50% duty cycle to save power and allow ambient light rejection via synchronous detection in the microcontroller. The phototransistor's output is read by the MCU's ADC. When an object breaks the beam, the ADC reading drops, triggering an action. The narrow 15-degree view angle of the HIR323C helps create a well-defined sensing zone, reducing false triggers from objects passing nearby but not through the beam.

12. Principle Introduction

An Infrared Light Emitting Diode (IR LED) is a semiconductor p-n junction diode that emits light when forward biased. When electrical current flows from the anode (p-type material) to the cathode (n-type material), electrons recombine with holes in the junction region, 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 HIR323C, the GaAlAs material system has a bandgap corresponding to photons in the near-infrared region around 850 nanometers. The water-clear epoxy lens is transparent to this wavelength and is shaped to produce the desired radiation pattern (view angle).

13. Development Trends

The trend in infrared emitter technology continues towards higher efficiency (more optical output power per electrical input watt), which allows for either longer range, lower power consumption, or both. There is also a drive towards miniaturization, with surface-mount device (SMD) packages becoming more prevalent than through-hole types like the T-1 for automated assembly. Integration is another trend, with combined emitter-sensor modules and intelligent sensors with built-in signal processing becoming common. Furthermore, adherence to and exceeding environmental regulations (like Halogen-Free requirements) remains a key focus for component manufacturers serving global markets. While the standard 850nm remains popular due to good silicon sensor response and low cost, other wavelengths like 940nm are gaining traction for applications where visibility of the faint red glow (present in some 850nm LEDs) is undesirable.