Infrared Emitter LED 940nm T-1 3/4 Package - 5.0mm Dia x 8.6mm H - Forward Voltage 1.6V - Radiant Intensity 40mW/sr - English Datasheet

1. Product Overview

This document details the specifications for a high-power infrared (IR) emitting diode. The device is engineered to emit light at a peak wavelength of 940 nanometers (nm), which is in the non-visible spectrum, making it ideal for applications where invisible illumination is required. The component is housed in a standard T-1 3/4 through-hole package with a water-clear lens, providing a wide radiation pattern.

1.1 Core Advantages and Target Market

The primary advantages of this IR emitter include its high radiant intensity output, a wide 45-degree viewing angle for broad coverage, and a design optimized for high current operation with low forward voltage characteristics. These features make it a cost-effective and reliable solution. The target applications are predominantly in consumer electronics and sensing, specifically for infrared remote control units for televisions, set-top boxes, and audio equipment, as well as for proximity or presence detection sensors in various devices.

2. In-Depth Technical Parameter Analysis

The performance of the device is defined under standard ambient temperature conditions (25°C). Understanding these parameters is critical for proper circuit design and reliable operation.

2.1 Absolute Maximum Ratings

These ratings define the stress limits beyond which permanent damage to the device may occur. Operation under or at these limits is not guaranteed. Key limits include a continuous forward current (I_F) of 100 mA, a peak forward current of 1 A under pulsed conditions (300 pps, 10μs pulse width), and a maximum power dissipation of 160 mW. The device can withstand a reverse voltage (V_R) of up to 5V, though it is explicitly noted that this is for test purposes only and the device is not designed for operation under reverse bias. The operating temperature range is from -40°C to +85°C.

2.2 Electrical and Optical Characteristics

These are the typical performance parameters under specified test conditions. The radiant intensity (I_E), a measure of optical power output per solid angle, is typically 40 milliwatts per steradian (mW/sr) when driven at 100 mA. The forward voltage (V_F) is typically 1.6 volts at a drive current of 50 mA, indicating relatively low electrical power loss. The spectral characteristics are centered at 940 nm with a spectral half-width (Δλ) of approximately 50 nm, defining the bandwidth of the emitted infrared light.

3. Performance Curve Analysis

The datasheet provides several graphs illustrating the device's behavior under varying conditions, which are essential for understanding non-linearities and temperature dependencies.

3.1 Spectral Distribution

The spectral distribution curve (Fig.1) shows the relative radiant intensity as a function of wavelength. It confirms the peak emission at 940 nm and the 50 nm half-width, indicating the spread of wavelengths emitted. This is important for matching with the sensitivity of receiving sensors or photodiodes.

3.2 Forward Current vs. Forward Voltage (I-V Curve)

The I-V curve (Fig.3) depicts the relationship between the current flowing through the diode and the voltage across it. It is non-linear, characteristic of a semiconductor diode. This curve is vital for determining the necessary drive voltage for a desired operating current and for calculating power dissipation (P_D = V_F × I_F).

3.3 Thermal Characteristics

Figure 2 shows the derating of the maximum allowable forward current as the ambient temperature increases. As temperature rises, the device's ability to dissipate heat decreases, so the maximum safe operating current must be reduced to prevent exceeding the junction temperature limit. Figure 4 shows how the relative radiant intensity decreases with increasing ambient temperature for a fixed drive current, a phenomenon known as thermal droop. This must be accounted for in designs requiring stable output over a wide temperature range.

3.4 Relative Radiant Intensity vs. Forward Current

Figure 5 illustrates that the light output is not linearly proportional to current, especially at higher currents where efficiency may drop due to heating and other effects. This graph helps in selecting an appropriate operating point to balance brightness, efficiency, and device lifetime.

3.5 Radiation Pattern

The polar diagram (Fig.6) visually represents the viewing angle. The 2θ½ specification of 45 degrees means the angle at which the radiant intensity drops to half of its value at 0 degrees (on-axis). This wide pattern is beneficial for applications like remote controls, where the exact alignment between transmitter and receiver is not guaranteed.

4. Mechanical and Packaging Information

4.1 Outline Dimensions

The device conforms to the T-1 3/4 (5mm) package standard. Key dimensions include a body diameter of approximately 5.0 mm, a total height of about 8.6 mm from the bottom of the leads to the top of the lens, and a lead spacing of 2.54 mm (0.1 inches) where the leads emerge from the package. A maximum protrusion of resin under the flange is specified as 1.0 mm. Detailed mechanical drawings with tolerances (typically ±0.25 mm) should be consulted for PCB footprint design.

4.2 Polarity Identification

For through-hole LEDs, the anode (positive lead) is typically the longer lead. The datasheet's outline drawing should be referenced to confirm the physical identification marker, which is often a flat spot on the package rim or a notch, indicating the cathode (negative lead) side.

5. Soldering and Assembly Guidelines

Proper handling is crucial to prevent damage during manufacturing.

5.1 Lead Forming

If leads need to be bent, it must be done at a point at least 3 mm away from the base of the epoxy lens. The package body should not be used as a fulcrum during bending. This operation must be performed at room temperature and before the soldering process.

5.2 Soldering Parameters

Two soldering methods are addressed:
Soldering Iron: Maximum temperature of 360°C for a maximum of 3 seconds. The iron tip must be no closer than 1.6 mm from the base of the epoxy bulb.
Wave Soldering: Pre-heat temperature should not exceed 100°C for up to 60 seconds. The solder wave temperature should be a maximum of 260°C with a contact time under 5 seconds. The device should be dipped no lower than 2.0 mm from the base of the epoxy bulb.
Critical Note: Infrared (IR) reflow soldering is explicitly stated as unsuitable for this through-hole package type. Excessive heat or time can melt the plastic lens or cause internal failure.

5.3 Cleaning

If cleaning is necessary after soldering, only alcohol-based solvents like isopropyl alcohol (IPA) should be used.

6. Storage and Handling

For long-term storage outside of the original moisture-barrier bag, it is recommended to keep the devices in an environment not exceeding 30°C and 70% relative humidity. If removed from the original packaging, they should be used within three months. For extended storage, placing them in a sealed container with desiccant or in a nitrogen ambient is advised.

7. Application Design Considerations

7.1 Drive Circuit Design

An LED is a current-driven device. The datasheet strongly recommends using a series current-limiting resistor for each LED when multiple units are connected in parallel (Circuit Model A). This is because the forward voltage (V_F) can vary slightly from device to device. Connecting LEDs directly in parallel (Circuit Model B) without individual resistors can cause current hogging, where the LED with the lowest V_F draws disproportionately more current, leading to uneven brightness and potential overstress and failure of that device.

7.2 Electrostatic Discharge (ESD) Protection

The device is sensitive to electrostatic discharge. Preventive measures must be implemented in the handling and assembly environment:

• Personnel must wear grounded wrist straps or heel straps/conductive shoes on conductive flooring.
• Workstations, equipment, and storage racks must be properly grounded.
• Use ionizers to neutralize static charge that may accumulate on the plastic lens.
• Regular checks and training for personnel working in ESD-protected areas are essential.

7.3 Application Scope and Cautions

The component is intended for standard consumer and industrial electronics. The manufacturer specifies that consultation is required if the device is to be used in safety-critical applications (e.g., medical life support, aviation, transportation control) where failure could risk life or health.

8. Operational Principle and Technology Context

This device is a semiconductor light-emitting diode (LED) that operates on the principle of electroluminescence. When a forward voltage is applied across the p-n junction, electrons and holes recombine in the active region, releasing energy in the form of photons. The specific material composition of the semiconductor layers determines the wavelength of the emitted light; in this case, it is tuned for 940 nm infrared emission. Infrared LEDs of this type are mature, highly reliable components. Their development has focused on increasing efficiency (radiant intensity per input power), improving thermal management for higher drive currents, and ensuring compatibility with environmental regulations such as RoHS (Restriction of Hazardous Substances). The wide viewing angle package is a key design feature that enhances usability in applications requiring broad coverage rather than a focused beam.