IR Emitter and Detector LTE-S9711-J Datasheet - Side View Package - Peak Wavelength 940nm - Forward Voltage 1.2V - Radiant Intensity 3.0mW/sr - English Technical Document

1. Product Overview

The LTE-S9711-J is a discrete infrared component designed for applications requiring reliable infrared emission and detection. It belongs to a broad product line of optoelectronic devices. The primary function of this component is to emit or detect infrared light at a peak wavelength of 940 nanometers. Its side-view lens design allows for a wide viewing angle, making it suitable for applications where the optical axis is parallel to the mounting surface. The device is constructed with water-clear plastic and is engineered to be compatible with modern automated assembly processes.

1.1 Core Advantages and Target Market

The LTE-S9711-J offers several key advantages for designers. It meets RoHS and green product standards, ensuring environmental compliance. The package is supplied on 8mm tape on 13-inch diameter reels, making it fully compatible with high-speed automatic placement equipment. This compatibility significantly streamlines the manufacturing process for high-volume production. Furthermore, the device is rated for infrared reflow soldering processes, aligning with standard surface-mount technology (SMT) assembly lines. Its primary target markets include consumer electronics for remote control functions, industrial applications for IR wireless data transmission, and security systems for alarm and sensing functions. The side-view package is particularly advantageous in space-constrained designs where a top-emitting component would not fit.

2. In-Depth Technical Parameter Analysis

This section provides a detailed, objective interpretation of the electrical, optical, and thermal characteristics of the LTE-S9711-J as defined in its absolute maximum ratings and electrical/optical characteristics tables.

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. For the LTE-S9711-J, the maximum power dissipation is 100 mW at an ambient temperature (TA) of 25°C. This rating dictates the thermal design of the application circuit. The device can handle a high peak forward current of 1 Ampere, but only under specific pulsed conditions: a pulse width of 10 microseconds and a pulse repetition rate of 300 pulses per second. The continuous DC forward current rating is a more conservative 50 mA. The reverse voltage rating is 5 Volts, indicating the device has a very low tolerance for reverse bias and is not designed for such operation. The operating temperature range is from -40°C to +85°C, and the storage range is from -55°C to +100°C, which is standard for commercial-grade electronic components. The device can withstand infrared reflow soldering with a peak temperature of 260°C for a maximum of 10 seconds.

2.2 Electrical and Optical Characteristics

The typical operating parameters are specified at TA=25°C. The key optical parameter is the Radiant Intensity (I_E), which has a minimum value of 3.0 mW/sr when driven at a forward current (I_F) of 20mA. This parameter is binned, as detailed later. The peak emission wavelength (λ_Peak) is typically 940nm, which is in the near-infrared spectrum and invisible to the human eye. The spectral bandwidth (Δλ), or half-width, is typically 50nm, describing the spread of the emitted wavelengths around the peak. Electrically, the forward voltage (V_F) is typically 1.2V with a maximum of 1.5V at I_F=20mA. The reverse current (I_R) is very low, with a maximum of 10 μA at a reverse voltage (V_R) of 5V. The viewing angle (2θ_1/2) is typically 45 degrees, where θ_1/2 is the angle at which the radiant intensity drops to half of its on-axis value.

3. Binning System Explanation

The LTE-S9711-J utilizes a binning system for its Radiant Intensity to ensure consistency within a production batch and provide options for different performance levels. The bin code is indicated in the part number (e.g., the \"J\" in LTE-S9711-J). The available bins are:

• Bin J: Radiant Intensity between 3.0 mW/sr (min) and 4.5 mW/sr (max) at I_F=20mA.
• Bin K: Radiant Intensity between 4.0 mW/sr (min) and 6.0 mW/sr (max) at I_F=20mA.
• Bin L: Radiant Intensity with a minimum of 5.0 mW/sr at I_F=20mA (no upper limit specified in the provided data).

This system allows designers to select a component that meets their specific optical output requirements, balancing performance and cost.

4. Performance Curve Analysis

The datasheet includes several typical characteristic curves that are crucial for understanding device behavior under non-standard conditions.

4.1 Spectral Distribution

The spectral distribution curve (Fig.1) shows the relative radiant intensity as a function of wavelength. It confirms the peak at 940nm and the approximately 50nm spectral half-width. This curve is important for applications sensitive to specific wavelengths or when matching with a detector's spectral response.

4.2 Forward Current vs. Forward Voltage & Ambient Temperature

Figure 2 and Figure 3 illustrate the relationship between forward current (I_F) and forward voltage (V_F) at different ambient temperatures. These curves show that V_F has a negative temperature coefficient; it decreases as temperature increases for a given current. This is a typical behavior for semiconductor diodes. Understanding this is vital for designing stable drive circuits, especially over a wide temperature range.

4.3 Relative Radiant Intensity vs. Forward Current & Temperature

Figure 4 and Figure 5 show how the optical output power (relative to its value at I_F=20mA) varies with forward current and ambient temperature. The output increases with current but exhibits a sub-linear relationship at higher currents, potentially due to thermal effects. Figure 4 specifically shows that output power decreases as ambient temperature rises, which is a critical derating factor for high-temperature applications.

4.4 Radiation Diagram

The radiation diagram (Fig.6) is a polar plot depicting the spatial distribution of the emitted infrared light. The typical 45-degree viewing angle (2θ_1/2) is visually confirmed here. This diagram is essential for optical design, helping to align the emitter with a detector or to understand the coverage area of the IR signal.

5. Mechanical and Package Information

5.1 Outline Dimensions and Polarity

The component features a standard side-view, surface-mount package. The outline drawing provides all critical dimensions, including body size, lead spacing, and lens position. The cathode is typically identified by a visual marker such as a notch or a flat spot on the package body, as indicated in the drawing notes. The package height, width, and depth are specified to ensure proper clearance in the final assembly.

5.2 Recommended Soldering Pad Layout

A suggested land pattern (soldering pad dimensions) is provided to ensure a reliable solder joint and proper mechanical alignment during reflow. Adhering to these recommendations helps prevent tombstoning (component standing on end) and ensures good thermal and electrical connection to the printed circuit board (PCB).

6. Soldering and Assembly Guidelines

Proper handling is critical for the reliability of surface-mount devices.

6.1 Moisture Sensitivity and Storage

The LTE-S9711-J is rated Moisture-Sensitive Level 3 (MSL 3). This means the packaged components can be exposed to factory floor conditions (≤30°C/60% RH) for up to 168 hours (one week) before soldering without risk of moisture-induced damage (popcorning) during reflow. If the original moisture-proof bag is opened, it is recommended to complete the IR reflow process within this one-week period. For longer storage outside the original packaging, components must be stored in a dry cabinet or sealed container with desiccant. If the exposure time exceeds one week, a baking procedure (approximately 60°C for at least 20 hours) is required before assembly to remove absorbed moisture.

6.2 Reflow Soldering Profile

The device is compatible with infrared reflow soldering. The recommended profile follows JEDEC standards. Key parameters include: a pre-heat zone from 150°C to 200°C for up to 120 seconds, and a peak body temperature not exceeding 260°C for a maximum of 10 seconds. The device can withstand a maximum of two reflow cycles under these conditions. For manual soldering with an iron, the tip temperature should not exceed 300°C, and contact time should be limited to 3 seconds per solder joint. It is crucial to follow the solder paste manufacturer's specifications in conjunction with these guidelines.

6.3 Cleaning

If post-solder cleaning is necessary, only alcohol-based solvents like isopropyl alcohol should be used. Harsh or aggressive chemical cleaners may damage the plastic package or lens.

7. Packaging and Ordering Information

The standard packaging for the LTE-S9711-J is on 8mm wide embossed carrier tape. The tape is wound on a 13-inch (330mm) diameter reel. Each reel contains approximately 9,000 pieces. The packaging specifications comply with ANSI/EIA 481-1-A-1994. The tape has a cover seal to protect components, and there is a limit of two consecutive missing components (empty pockets) per reel. The part number, including the bin code (e.g., LTE-S9711-J, LTE-S9711-K), must be specified when ordering to receive the desired radiant intensity performance.

8. Application Notes and Design Considerations

8.1 Typical Application Circuits

As an infrared emitter, the LTE-S9711-J is a current-driven device. A series current-limiting resistor is mandatory to set the desired forward current (I_F) and protect the LED from excessive current, especially when powered from a voltage source like a battery or regulator. The resistor value is calculated using Ohm's Law: R = (V_supply - V_F) / I_F. Using the typical V_F of 1.2V at 20mA, a 5V supply would require a resistor of approximately (5V - 1.2V) / 0.02A = 190 Ohms. A standard 200 Ohm resistor would be suitable. For pulsed operation (e.g., remote control codes), the driver circuit must ensure the peak current does not exceed the 1A rating and adheres to the 10μs pulse width and 300pps duty cycle limits.

8.2 Design Considerations for Reliable Operation

Thermal Management: Although the package is small, the 100mW power dissipation limit must be respected. At the maximum DC current of 50mA and a typical V_F of 1.2V, the power dissipation is 60mW, which is within limits. However, in high ambient temperatures or enclosed spaces, the effective power rating decreases. Adequate PCB copper area (thermal relief pads) can help dissipate heat.
Optical Alignment: The side-view lens requires careful PCB layout to ensure the IR beam is directed correctly towards the receiver, reflector, or target area. The radiation diagram should be consulted.
Electrical Noise: In sensing applications, the detector side of a similar component may be susceptible to ambient light noise. Using modulated IR signals and corresponding demodulating receiver circuits is a common technique to improve signal-to-noise ratio and immunity to ambient light interference.

9. Technical Comparison and Differentiation

The LTE-S9711-J differentiates itself primarily through its side-view package, which is less common than top-view IR LEDs. This makes it uniquely suited for applications where the PCB is mounted vertically or where the IR path is parallel to the board surface. Its 940nm wavelength is the standard for consumer remote controls, offering a good balance between silicon photodetector sensitivity and low visible light emission. Compared to 850nm emitters sometimes used in surveillance, 940nm is completely invisible. The availability of performance bins (J, K, L) provides flexibility in optical power selection, which can be an advantage over devices with a single, fixed output specification.

10. Frequently Asked Questions (FAQs)

Q: What is the difference between this device as an emitter and a detector?
A: The LTE-S9711-J part number refers to a component that can be an infrared emitter (an IR LED). A photodiode or phototransistor for detection would have a different part number, though they may share a similar package. The datasheet provided focuses on the emitter characteristics.
Q: Can I drive this LED directly from a microcontroller pin?
A: Most microcontroller GPIO pins have limited current sourcing/sinking capability (often 20-40mA). While it might be possible at 20mA, it is generally safer and recommended to use a transistor (e.g., NPN or MOSFET) as a switch driven by the microcontroller to control the LED current, especially for pulsed or higher-current operation.
Q: Why is the viewing angle important?
A: The viewing angle determines the spatial coverage of the IR beam. A wide angle (like 45°) is good for applications requiring broad coverage, such as proximity sensors or short-range data links where alignment is not critical. A narrower angle would provide more focused intensity for longer-range or directed communication.
Q: How do I select the correct bin code?
A> Choose the bin based on the required minimum radiant intensity for your application. Bin J (3.0-4.5 mW/sr) is the base level. If your design needs more optical power for longer range or to overcome higher losses, select Bin K or Bin L. Consider the trade-off with power consumption and potential cost.

11. Practical Application Example

Scenario: Designing a simple object detection sensor.
A common design uses an IR emitter and a separate phototransistor detector placed side-by-side. When an object comes near, it reflects the emitted IR light back to the detector. For this setup using the LTE-S9711-J as the emitter:
1. The side-view package allows both the emitter and detector to be mounted flat on the PCB, facing the same direction parallel to the board.
2. The emitter is driven with a pulsed current (e.g., 20mA pulses at 1kHz) through a current-limiting resistor to conserve power and allow for synchronous detection.
3. The 940nm wavelength is ideal as it is invisible and most phototransistors are sensitive to it.
4. The typical 45° viewing angle of the emitter provides a reasonable detection field. The spacing between the emitter and detector, along with potential baffles, is tuned to set the detection range and avoid direct crosstalk.
5. The receiver circuit amplifies and filters the phototransistor's signal, looking for the modulated 1kHz component reflected by an object. This modulation helps reject constant ambient light (like sunlight or room lights).

12. Operating Principle

The LTE-S9711-J, when functioning as an infrared emitter, is a light-emitting diode (LED). Its core is a semiconductor chip made of materials like Gallium Arsenide (GaAs). When a forward voltage is applied, electrons and holes recombine in the active region of the semiconductor, releasing energy in the form of photons (light particles). The specific material composition (e.g., GaAs) determines the bandgap energy, which directly defines the wavelength of the emitted light—in this case, around 940nm, which is in the infrared spectrum. The side-view lens is made of water-clear epoxy that is transparent to this wavelength and is molded to shape the radiation pattern of the emitted light.

13. Technology Trends

The field of discrete infrared components continues to evolve. Trends include the development of devices with higher radiant intensity and efficiency from the same package size, enabling longer range or lower power consumption. There is also a push towards higher-speed modulation capabilities for faster data transmission in applications like IrDA or optical sensing. Integration is another trend, with combined emitter-detector pairs in a single package becoming more common for simplified sensor design. Furthermore, advancements in packaging materials and processes aim to improve thermal performance, allowing for higher drive currents and reliability. The demand for miniaturization persists, driving the development of even smaller package footprints while maintaining or improving optical performance.