IR Emitter and Detector Data Sheet - Clear Package - Forward Voltage 1.6V - Radiant Intensity up to 7.669 mW/sr - English Technical Document

1. Product Overview

This document details the specifications for a miniature, low-cost infrared (IR) emitter and detector component housed in a clear transparent plastic package. The device is designed for end-looking applications, meaning the active sensing/emitting area is positioned at the end of the package. It is selected and binned according to specific radiant intensity and aperture radiant incidence ranges, ensuring consistent performance for applications requiring precise optical output or sensitivity. The clear package allows for efficient transmission of infrared light while providing physical protection for the semiconductor die.

2. In-Depth Technical Parameter Analysis

2.1 Absolute Maximum Ratings

The device is rated for reliable operation within the following absolute limits, beyond which permanent damage may occur. The power dissipation is specified at 90 mW. For pulsed operation, it can handle a peak forward current of 1 Ampere under conditions of 300 pulses per second with a 10 microsecond pulse width. The maximum continuous forward current is 60 mA. The component can withstand a reverse voltage of up to 5 Volts. The operating temperature range is from -40°C to +85°C, while the storage temperature range extends from -55°C to +100°C. For assembly, the leads can be soldered at a temperature of 260°C for a duration of 5 seconds, measured at a distance of 1.6mm from the package body.

2.2 Electrical and Optical Characteristics

All electrical and optical parameters are specified at an ambient temperature (T_A) of 25°C. The key parameters define the device's performance under standard test conditions.

• Aperture Radiant Incidence (E_e): This parameter, measured in mW/cm², represents the optical power density incident on the detector's active area. It is tested with a forward current (I_F) of 20mA. The values are binned, ranging from a minimum of 0.096 mW/cm² (Bin A1) up to a typical maximum of 1.020 mW/cm² (Bin C).
• Radiant Intensity (I_E): Measured in mW/sr (milliwatts per steradian), this defines the emitted optical power per unit solid angle for the IR emitter. Also tested at I_F=20mA, it ranges from 0.722 mW/sr (Bin A1) to 7.669 mW/sr (Bin C).
• Peak Emission Wavelength (λ_Peak): The infrared emitter's output is centered at a nominal wavelength of 940 nanometers.
• Spectral Line Half-Width (Δλ): The spectral bandwidth, where the intensity is at least half of the peak value, is typically 50 nm, indicating a relatively narrowband IR source.
• Forward Voltage (V_F): The voltage drop across the device when conducting 20mA is typically 1.6 Volts, with a maximum of 1.6V.
• Reverse Current (I_R): When a reverse bias of 5V is applied, the leakage current is 100 µA maximum.
• Viewing Angle (2θ_1/2): The angular spread at which the radiant intensity falls to half of its value at 0 degrees (on-axis) is 60 degrees. This defines the beam pattern or field of view.

3. Binning System Explanation

The component utilizes a binning system primarily based on its optical output characteristics. This ensures that devices within a specific bin have closely matched performance, which is critical for applications requiring consistency, such as in arrays or paired emitter-detector systems.

• Radiant Intensity / Aperture Radiant Incidence Binning: The device is categorized into bins labeled A1, A, B, C, and D. Each bin corresponds to a specific range of minimum and typical/maximum values for both Radiant Intensity (I_E) and Aperture Radiant Incidence (E_e). For example, a device in Bin C will have an I_E between 3.910 and 7.669 mW/sr and an E_e between 0.520 and 1.020 mW/cm² when driven at 20mA. This allows designers to select components with the precise optical power level required for their application, optimizing signal strength and system performance.

4. Performance Curve Analysis

The data sheet includes several graphs illustrating the device's behavior under varying conditions.

• Figure 1 - Spectral Distribution: This curve shows the relative radiant intensity as a function of wavelength. It confirms the peak emission at 940nm and the approximate 50nm half-width, providing insight into the spectral purity of the IR output.
• Figure 2 - Forward Current vs. Ambient Temperature: This graph depicts the derating of the maximum allowable continuous forward current as the ambient temperature increases. It is essential for thermal management and ensuring the device operates within its safe operating area (SOA).
• Figure 3 - Forward Current vs. Forward Voltage: This is the current-voltage (I-V) characteristic curve. It shows the relationship between the applied forward voltage and the resulting current, highlighting the typical turn-on voltage and dynamic resistance of the device.
• Figure 4 - Relative Radiant Intensity vs. Ambient Temperature: This curve illustrates how the optical output power (relative to its value at 20mA and 25°C) changes with temperature. Typically, LED output decreases as temperature rises, and this graph quantifies that relationship.
• Figure 5 - Relative Radiant Intensity vs. Forward Current: This shows the optical output power as a function of drive current. It is generally a super-linear relationship, but the curve helps designers understand the efficiency and saturation points at different current levels.
• Figure 6 - Radiation Diagram: This polar plot visually represents the viewing angle or radiation pattern. The concentric circles indicate relative intensity (from 0 at the center to 1.0 at the outer edge), and the angular lines show the distribution. The 2θ_1/2 = 60° specification is confirmed by the points where the curve intersects the 0.5 relative intensity circle.

5. Mechanical and Packaging Information

5.1 Package Dimensions

The device uses a miniature plastic end-looking package. Key dimensional notes include: all dimensions are in millimeters (with inches in parentheses); standard tolerance is ±0.25mm unless stated otherwise; the maximum protrusion of resin under the flange is 1.5mm; and lead spacing is measured at the point where the leads exit the package body. The exact dimensional drawing is referenced in the data sheet, defining the overall length, body diameter, lead diameter, and spacing critical for PCB footprint design.

5.2 Polarity Identification

For an IR emitter/detector in a radial leaded package, polarity is typically indicated by the physical features of the device, such as a flat side on the package body or one lead being shorter than the other. The specific identification method should be cross-referenced with the detailed package drawing. Correct polarity connection is essential for proper operation.

6. Soldering and Assembly Guidelines

The component is suitable for standard soldering processes. The critical parameter specified is the lead soldering temperature: 260°C for a maximum of 5 seconds, with the measurement point defined as 1.6mm (0.063") from the package body. This guideline is crucial for wave soldering or hand soldering to prevent thermal damage to the internal semiconductor die or the plastic package. For reflow soldering, a standard profile for through-hole components with similar thermal limits should be used. Components should be stored within the specified -55°C to +100°C temperature range in a dry environment to prevent moisture absorption, which could cause "popcorning" during reflow.

7. Application Recommendations

7.1 Typical Application Scenarios

This IR emitter/detector pair is suitable for a wide range of proximity sensing, object detection, and data transmission applications. Common uses include:

• Object/Proximity Sensing: In vending machines, printers, or industrial equipment to detect the presence or absence of an object.
• Slot Sensors: For detecting paper in printers or tickets in validators.
• Simple Data Links: Low-speed, short-distance infrared data transmission for remote controls or isolated communication channels.
• Encoders: In rotary or linear encoders for position feedback, where an interrupter blade passes between the emitter and detector.

7.2 Design Considerations

When designing with this component, several factors must be considered:

• Current Limiting: For the emitter, a series resistor is mandatory to limit the forward current to the desired level (≤60mA continuous, ≤1A pulsed). The value is calculated using the supply voltage (V_CC), the desired I_F, and the typical V_F (e.g., R = (V_CC - V_F) / I_F).
• Detector Biasing and Amplification: The photodetector typically requires a reverse bias (up to 5V) and its output current is very small (related to E_e). A transimpedance amplifier (TIA) is often needed to convert this small photocurrent into a usable voltage signal.
• Optical Alignment: For paired emitter-detector applications, precise mechanical alignment is crucial for maximizing signal strength. The 60-degree viewing angle provides some tolerance.
• Ambient Light Rejection: Since the device is sensitive to 940nm light, it can be affected by sunlight or other IR sources. Using modulated IR signals and synchronous detection (e.g., a 38kHz carrier common in remote controls) can significantly improve noise immunity.
• Thermal Management: The derating curve (Fig. 2) must be consulted for high-temperature environments to avoid exceeding the maximum power dissipation.

8. Technical Comparison and Differentiation

Compared to other IR components, this device's key differentiators are its clear plastic package and its precise optical binning. Many IR LEDs and photodiodes use tinted (e.g., blue, black) packages that filter visible light but may also attenuate the desired IR wavelength slightly. A clear package offers potentially higher transmission efficiency at 940nm. The rigorous binning on radiant intensity and incidence allows for predictable and consistent system performance, which is an advantage over unbinned or loosely binned parts where performance can vary significantly from unit to unit. The miniature size and low cost make it suitable for high-volume consumer and commercial applications.

9. Frequently Asked Questions (Based on Technical Parameters)

Q: What is the difference between Aperture Radiant Incidence (E_e) and Radiant Intensity (I_E)?

A: E_e is a measure of power density (mW/cm²) incident on a surface (the detector's active area). I_E is a measure of the emitter's power output per solid angle (mW/sr). They are related but describe the performance of the detector and emitter sides, respectively.

Q: Can I drive the emitter with a 5V supply directly?

A: No. With a typical V_F of 1.6V, connecting 5V directly would cause excessive current, likely destroying the LED. You must use a current-limiting resistor.

Q: How do I select the right bin for my application?

A: Choose based on the required signal strength. For long-distance or low-reflectivity sensing, a higher bin (C, D) provides more optical power. For short-range or high-sensitivity detector circuits, a lower bin may be sufficient and more cost-effective. Consistency across multiple units in a system may also dictate bin selection.

Q: What does the viewing angle specification mean for the detector?

A: For the detector, the 60-degree viewing angle (2θ_1/2) defines its field of view. Light incident within this ±30-degree cone from the axis will be detected with reasonable sensitivity. Light outside this angle will be largely ignored, which can help reject stray light from unwanted directions.

10. Practical Application Example

Design Case: Paper-out Sensor in a Printer

In this application, the IR emitter and detector are mounted on opposite sides of the paper path. When paper is present, it reflects the IR beam from the emitter to the detector. When the paper tray is empty, the beam travels unimpeded and is not reflected back to the detector (or hits a different reflective surface). The detector circuit monitors the received signal level. A key design step is selecting an appropriate bin (e.g., Bin B) to ensure the reflected signal from paper is strong enough to be reliably distinguished from the "no paper" state, even with variations in paper reflectivity. The drive current for the emitter is set to 20mA via a resistor, providing the reference optical output. The detector's output is fed into a comparator with a threshold set between the "paper present" and "paper absent" voltage levels. The 60-degree viewing angle helps ensure the sensor works even with slight misalignment during printer assembly.

11. Operational Principle Introduction

The device consists of two primary semiconductor components: an Infrared Light Emitting Diode (IR LED) and a Photodiode. The IR LED operates on the principle of electroluminescence. When forward biased, electrons and holes recombine in the semiconductor's active region, releasing energy in the form of photons. The material composition (typically based on Gallium Arsenide, GaAs) is engineered so that this photon energy corresponds to a wavelength in the infrared spectrum, specifically around 940nm. The Photodiode operates in reverse. Incident photons with energy greater than the semiconductor's bandgap are absorbed, creating electron-hole pairs. These charge carriers are swept apart by the internal electric field of the reverse-biased junction, generating a photocurrent that is proportional to the intensity of the incident light. The clear plastic package acts as a lens and window, protecting the delicate semiconductor chips while allowing efficient passage of the 940nm infrared radiation.

12. Technology Trends and Developments

In the field of optoelectronics for sensing, several trends are relevant to components like this one. There is a continuous drive toward miniaturization, with surface-mount device (SMD) packages becoming more prevalent than through-hole types for automated assembly. Higher integration is another trend, where the emitter, detector, and signal conditioning circuitry (amplifier, comparator) are combined into a single module, simplifying design for end-users. The demand for improved signal-to-noise ratio and ambient light rejection is pushing the use of specific wavelength bands and advanced optical filtering integrated into the package. Furthermore, applications in the Internet of Things (IoT) and wearable devices are driving the need for components with lower power consumption while maintaining adequate sensing range and reliability. While this specific component represents a mature and cost-effective solution, newer designs often incorporate these evolving requirements.