5mm Infrared LED HIR7393C Datasheet - 5.0mm Diameter - 1.45V Forward Voltage - 850nm Wavelength - 150mW Power Dissipation - English Technical Document

1. Product Overview

The device is a high-intensity infrared emitting diode (IRED) housed in a standard T-1 3/4 (5.0mm) package with a water-clear plastic lens. It is designed to emit light at a peak wavelength of 850nm, making it spectrally matched with common silicon phototransistors, photodiodes, and infrared receiver modules for reliable operation in sensing and communication systems.

1.1 Key Features and Core Advantages

• High Radiant Intensity: Delivers typical radiant intensity of 15 mW/sr at a forward current of 20mA, enabling strong signal transmission.
• Low Forward Voltage: Features a typical forward voltage (V_F) of 1.45V at 20mA, contributing to lower power consumption in circuits.
• High Reliability: Constructed with robust materials and processes suitable for industrial applications.
• Lead-Free & RoHS Compliant: Manufactured to meet environmental regulations.
• Standard Lead Spacing: 2.54mm (0.1 inch) pin spacing for compatibility with standard breadboards and PCBs.

1.2 Target Market and Applications

This infrared LED is primarily targeted at designers and engineers working on electronic systems requiring non-visible light sources. Its main application is in infrared applied systems, which broadly includes:

• Object detection and proximity sensing
• Infrared data transmission (e.g., remote controls, short-range communication)
• Optical encoders and position sensing
• Barrier systems and security sensors
• Industrial automation and machine vision lighting

2. In-Depth Technical Parameter Analysis

2.1 Absolute Maximum Ratings

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

• Continuous Forward Current (I_F): 100 mA
• Peak Forward Current (I_FP): 1.0 A (Pulse Width ≤100μs, Duty Cycle ≤1%)
• Reverse Voltage (V_R): 5 V
• Operating Temperature (T_opr): -40°C to +85°C
• Storage Temperature (T_stg): -40°C to +100°C
• Power Dissipation (P_d): 150 mW (at or below 25°C free air temperature)
• Soldering Temperature (T_sol): 260°C for ≤5 seconds

2.2 Electro-Optical Characteristics (Ta=25°C)

These are the typical performance parameters under specified test conditions.

• Radiant Intensity (I_e): Min. 7.8, Typ. 15 mW/sr @ I_F=20mA. Can reach ~50 mW/sr @ I_F=100mA under pulsed conditions.
• Peak Wavelength (λ_p): 850 nm (Typical) @ I_F=20mA. This is near the peak sensitivity of silicon detectors.
• Spectral Bandwidth (Δλ): 45 nm (Typical) @ I_F=20mA. Defines the spectral width at half the maximum intensity.
• Forward Voltage (V_F): Typ. 1.45V, Max. 1.65V @ I_F=20mA. Typ. 1.80V, Max. 2.40V @ I_F=100mA (pulsed).
• Reverse Current (I_R): Max. 10 μA @ V_R=5V.
• View Angle (2θ_1/2): 45 degrees (Typical) @ I_F=20mA. This is the full angle at half intensity.

2.3 Thermal Characteristics

The power dissipation rating of 150mW is specified at or below 25°C ambient temperature. As ambient temperature increases, the maximum allowable power dissipation decreases. Designers must refer to the derating curve (implied in the datasheet) to ensure the junction temperature does not exceed safe limits, which is critical for long-term reliability. The operating temperature range of -40°C to +85°C makes it suitable for harsh environments.

3. Binning System Explanation

The HIR7393C is available in different performance grades, or "bins," based on radiant intensity measured at I_F = 20mA. This allows selection of a device that meets specific brightness requirements.

Radiant Intensity Binning (Unit: mW/sr):

• Bin M: Min 7.8, Max 12.5
• Bin N: Min 11.0, Max 17.6
• Bin P: Min 15.0, Max 24.0
• Bin Q: Min 21.0, Max 34.0

Selection of a higher bin (e.g., Q) ensures a higher minimum radiant intensity, which can be important for maximizing signal-to-noise ratio in sensing applications or increasing the range of IR transmission.

4. Performance Curve Analysis

4.1 Forward Current vs. Ambient Temperature

The derating curve shows the relationship between the maximum allowable continuous forward current and the ambient temperature. As temperature rises, the maximum current must be reduced to prevent overheating and ensure the junction temperature stays within safe limits. This curve is essential for designing reliable circuits, especially in high-temperature environments.

4.2 Spectral Distribution

The spectral distribution curve plots relative radiant intensity against wavelength. It confirms the peak emission at 850nm and the approximately 45nm spectral bandwidth. The curve is relatively symmetrical and centered on 850nm, which is ideal for matching with silicon-based detectors that have peak sensitivity around 800-900nm.

4.3 Radiant Intensity vs. Forward Current

This curve demonstrates that radiant intensity increases with forward current, but the relationship is not perfectly linear, especially at higher currents due to heating and efficiency droop. Operating in pulsed mode (as specified for the 100mA test) allows for higher peak intensity without the thermal buildup associated with continuous operation.

4.4 Relative Radiant Intensity vs. Angular Displacement

This polar plot illustrates the spatial emission pattern of the LED. The 45-degree viewing angle (full width at half maximum) indicates a moderately wide beam. The intensity is highest at 0 degrees (on-axis) and decreases smoothly towards the edges. This pattern is important for designing optical systems to ensure adequate coverage or focus.

5. Mechanical and Package Information

5.1 Package Dimensions

The device uses a standard T-1 3/4 (5.0mm diameter) round package. Key dimensions include:

• Overall diameter: 5.0mm.
• Lead spacing: 2.54mm (standard).
• Lead diameter: Typically 0.45mm.
• Package height: Approximately 8.6mm from the seating plane to the top of the dome.
• Tolerances: ±0.25mm unless otherwise specified on the detailed dimension drawing.

The exact mechanical drawing should be consulted for critical placement and footprint design on a PCB.

5.2 Polarity Identification

The LED has a flat spot or notch on the rim of the plastic lens, which typically indicates the cathode (negative) side. The cathode lead is also usually the shorter lead, although this can be trimmed during assembly. Always verify polarity before soldering to prevent reverse bias damage.

6. Soldering and Assembly Guidelines

6.1 Lead Forming

• Bend leads at a point at least 3mm from the base of the epoxy bulb.
• Perform lead forming before soldering.
• Avoid applying stress to the LED package during bending.
• Cut leads at room temperature.
• Ensure PCB holes align perfectly with LED leads to avoid mounting stress.

6.2 Storage

• Recommended storage: ≤30°C and ≤70% Relative Humidity (RH).
• Shelf life under these conditions: 3 months from shipment.
• For longer storage (up to 1 year): Use a sealed container with a nitrogen atmosphere and moisture absorbent.
• Avoid rapid temperature transitions in humid environments to prevent condensation.

6.3 Soldering Process

General Rule: Maintain a minimum distance of 3mm from the solder joint to the epoxy bulb.

Hand Soldering:

• Iron tip temperature: Max 300°C (for a 30W max iron).
• Soldering time per lead: Max 3 seconds.

Dip/Wave Soldering:

• Preheat temperature: Max 100°C (for max 60 seconds).
• Solder bath temperature: Max 260°C.
• Dwell time in solder: Max 5 seconds.

Critical Notes:

• Avoid stress on leads during high-temperature phases.
• Do not perform dip/hand soldering more than once.
• Protect the LED from mechanical shock/vibration until it cools to room temperature after soldering.
• Avoid rapid cooling processes.
• Use the lowest possible temperature that achieves a reliable solder joint.

6.4 Cleaning

• If necessary, clean only with isopropyl alcohol at room temperature for ≤1 minute.
• Dry at room temperature before use.
• Avoid ultrasonic cleaning unless absolutely necessary and pre-qualified, as it can cause mechanical damage.

6.5 Heat Management

Thermal management must be considered during the circuit design phase. The current must be appropriately derated based on the ambient temperature, as shown in the derating curve. Adequate PCB copper area (thermal relief) around the LED leads can help dissipate heat. For high-current or high-duty-cycle pulsed operation, additional cooling measures may be required.

7. Packaging and Ordering Information

7.1 Packaging Specification

• Primary Pack: 500 pieces per anti-static bag.
• Inner Carton: 5 bags (2500 pieces) per inner carton.
• Master/Outside Carton: 10 inner cartons (25,000 pieces) per outside carton.

7.2 Label Information

The product label contains several key identifiers:

• CPN: Customer's Product Number.
• P/N: Manufacturer's Product Number (e.g., HIR7393C).
• QTQ: Packing Quantity in the bag.
• CAT: Luminous Intensity Rank (Bin code, e.g., M, N, P, Q).
• HUE: Dominant Wavelength Rank.
• REF: Forward Voltage Rank.
• LOT No: Manufacturing Lot Number for traceability.

8. Application Suggestions and Design Considerations

8.1 Typical Application Circuits

The most common circuit is a simple series connection with a current-limiting resistor. The resistor value is calculated using Ohm's Law: R = (V_supply - V_F) / I_F. For example, with a 5V supply, V_F=1.45V, and desired I_F=20mA: R = (5 - 1.45) / 0.02 = 177.5Ω. A standard 180Ω resistor would be suitable. For pulsed operation for higher intensity, a transistor or MOSFET switch controlled by a microcontroller is typical.

8.2 Design Considerations

• Current Drive: Always drive LEDs with a constant current or a current-limited voltage source to prevent thermal runaway.
• Reverse Voltage Protection: The maximum reverse voltage is only 5V. In circuits where reverse bias is possible (e.g., AC coupling, inductive loads), include a protection diode in parallel with the LED (cathode to anode).
• Optical Design: Consider the 45-degree viewing angle when designing lenses, reflectors, or apertures for your system. The water-clear lens is suitable for use with external optical elements.
• Detector Matching: Ensure the paired photodetector (phototransistor, photodiode, receiver IC) is sensitive in the 850nm region for optimal performance.

9. Technical Comparison and Differentiation

Compared to standard visible LEDs or other infrared LEDs, the HIR7393C offers specific advantages:

• vs. Visible LEDs: Emits in the near-infrared spectrum, invisible to the human eye, making it ideal for discreet sensing and communication.
• vs. 940nm IR LEDs: 850nm light is more easily detected by standard silicon detectors (which are more sensitive around 800-900nm) and is often visible as a faint red glow with some digital cameras, aiding in alignment during prototyping.
• vs. Lower-Power IR LEDs: Its higher radiant intensity bins (P, Q) provide stronger output, enabling longer range or better signal integrity in noisy environments.
• vs. Non-standard Packages: The T-1 3/4 package is ubiquitous, making it easy to source, prototype with, and replace.

10. Frequently Asked Questions (FAQ)

Q1: Can I drive this LED directly from a microcontroller pin?
A: It depends on the microcontroller's pin current sourcing capability. Many MCU pins can source 20mA, but it's often at the upper limit. It's generally safer and recommended to use a simple transistor (e.g., NPN like 2N3904) as a switch to drive the LED, controlled by the MCU pin.

Q2: Why is the maximum pulsed current (1A) so much higher than the continuous current (100mA)?
A: Heat generation is proportional to current squared (I²R). A very short pulse (≤100μs) with a low duty cycle (≤1%) does not allow enough time for significant heat to build up in the LED chip, preventing thermal damage. Continuous operation at high current would cause overheating.

Q3: What does "spectrally matched" mean?
A: It means the peak emission wavelength of this LED (850nm) aligns well with the peak spectral sensitivity of common silicon-based photodetectors. This matching maximizes the electrical signal generated in the detector for a given amount of IR light, improving system efficiency and signal-to-noise ratio.

Q4: How do I choose the right bin (M, N, P, Q)?
A: Choose based on your system's sensitivity requirements. If you need consistent, high output (e.g., for longer range or through attenuating materials), specify Bin P or Q. For cost-sensitive applications where minimum brightness is less critical, Bin M or N may be sufficient. Consult the binning table for exact min/max values.

11. Practical Design and Usage Examples

11.1 Simple Object Proximity Sensor

A classic application is a reflective object sensor. The HIR7393C is placed adjacent to a phototransistor. The LED illuminates the area in front of the sensor. When an object comes close, it reflects the IR light back to the phototransistor, causing its collector current to increase. This change can be detected by a comparator or microcontroller ADC to trigger an action. The 45-degree beam of the LED provides a good balance between spot size and intensity for such sensing.

11.2 Infrared Data Link

For simple serial data transmission (like a TV remote), the LED can be pulsed at high current (e.g., 100mA pulses) according to a modulated digital signal (e.g., 38kHz carrier). The high radiant intensity in pulsed mode allows for reasonable range. A matching IR receiver module (with built-in demodulator) tuned to the same frequency would be used on the receiving end.

12. Principle of Operation

An Infrared Light Emitting Diode (IRED) is a semiconductor p-n junction diode. When forward biased, electrons from the n-region and holes from the p-region are injected into the active region. When these charge carriers recombine, they release energy. In an IRED made of Gallium Aluminum Arsenide (GaAlAs), this energy is released primarily as photons in the infrared spectrum (around 850nm in this case). The water-clear epoxy package acts as a lens, shaping the emitted light into the characteristic beam pattern. The efficiency of this electroluminescent process determines the radiant intensity for a given drive current.

13. Technology Trends

While the fundamental T-1 3/4 package and 850nm technology are mature, trends in IR LEDs include:

• Higher Efficiency: Ongoing material science improvements aim to produce more optical power (radiant intensity) per unit of electrical input power, reducing heat generation and energy consumption.
• Narrower Spectra: Some applications, like gas sensing or high-speed communication, benefit from LEDs with very specific, narrow emission wavelengths.
• Integrated Devices: Trends include combining the IR LED and photodetector in a single package (opto-coupler style) or with driving circuitry for simpler system integration.
• Miniaturization: While 5mm remains popular, surface-mount device (SMD) packages are increasingly common for automated assembly and compact designs.
• Eye Safety: Increased focus on ensuring IR emissions, especially from high-power devices, comply with international eye safety standards (IEC 62471).

The HIR7393C represents a reliable, well-understood component that continues to serve as a fundamental building block in a wide array of electronic sensing and control systems.