IR Emitter and Detector LTE-C216-P-W Datasheet - 1206 Package (3.2x1.6x1.1mm) - Peak Wavelength 850nm - Forward Voltage 1.4V - Power Dissipation 100mW - English Technical Document

1. Product Overview

This document details the specifications for a discrete infrared (IR) emitter and detector component. This device is designed for applications requiring reliable infrared signal transmission and reception. It combines an infrared emitting diode (IRED) and a sensing element within a single, compact surface-mount package. The core technology is based on Gallium Arsenide (GaAs) and Aluminum Gallium Arsenide (AlGaAs) materials, optimized for operation at a peak wavelength of 850 nanometers. This wavelength is commonly used in consumer electronics and data transmission due to its good balance between performance and component availability.

The primary design goals are to provide a solution featuring high radiant intensity, good speed characteristics, and a wide viewing angle to facilitate alignment and signal capture. The component is packaged in a standard 1206 footprint, making it compatible with automated pick-and-place assembly lines and standard infrared reflow soldering processes. It is classified as a RoHS-compliant and Green product.

1.1 Key Features and Applications

The device incorporates several key features that make it suitable for modern electronic manufacturing:

• Compliance with RoHS and Green Product standards.
• Packaged in 8mm carrier tape on 7-inch diameter reels for automated assembly.
• Compatible with automatic placement equipment.
• Designed to withstand standard infrared reflow soldering profiles.
• Conforms to EIA standard package dimensions.
• Emits at a peak wavelength (λp) of 850nm.
• Utilizes the common 1206 surface-mount device (SMD) package type.

Typical applications for this component include, but are not limited to:

• Infrared emitter for remote control units (e.g., for TVs, audio systems).
• PCB-mounted infrared sensor for proximity detection, object sensing, or data reception.
• Infrared wireless data transmission links for short-range communication.
• Security alarm systems utilizing IR beams.

2. Technical Specifications Deep Dive

This section provides a detailed, objective analysis of the device's electrical, optical, and thermal characteristics. All parameters are specified at an ambient temperature (TA) of 25°C unless otherwise noted.

2.1 Absolute Maximum Ratings

These ratings define the limits beyond which permanent damage to the device may occur. Operation under or at these conditions is not guaranteed and should be avoided in reliable designs.

• Power Dissipation (Pd): 100 mW. This is the maximum total power the package can dissipate as heat.
• Peak Forward Current (IFP): 800 mA. This is the maximum allowable pulsed current, specified under conditions of 300 pulses per second with a 10-microsecond pulse width.
• DC Forward Current (IF): 60 mA. This is the maximum continuous forward current for steady-state operation.
• Reverse Voltage (VR): 5 V. The maximum voltage that can be applied in the reverse direction across the IRED.
• Operating Temperature Range: -40°C to +85°C. The ambient temperature range over which the device is designed to function.
• Storage Temperature Range: -55°C to +100°C. The temperature range for non-operational storage.
• Infrared Soldering Condition: Maximum of 260°C for 10 seconds. This defines the peak reflow temperature limit for lead-free soldering processes.

2.2 Electrical and Optical Characteristics

These are the typical performance parameters under normal operating conditions. Designers should use the typical (Typ.) or maximum (Max.) values as appropriate for their circuit calculations.

• Radiant Intensity (IE): 3.0 mW/sr (Typ.) at a forward current (IF) of 20mA. This measures the optical power emitted per unit solid angle along the axis.
• Peak Emission Wavelength (λPeak): 850 nm (Typ.). The wavelength at which the optical output power is maximum.
• Spectral Line Half-Width (Δλ): 50 nm (Typ.). The wavelength range over which the emitted power is at least half of the peak power, indicating the spectral purity.
• Forward Voltage (VF): 1.4 V (Typ.), 1.8 V (Max.) at IF=20mA. The voltage drop across the IRED when conducting.
• Reverse Current (IR): 10 μA (Max.) at a reverse voltage (VR) of 5V. The small leakage current when the device is reverse-biased.
• Rise/Fall Time (Tr/Tf): 20 nS (Typ.). The time for the optical output to rise from 10% to 90% (or fall from 90% to 10%) of its final value, indicating switching speed.
• Viewing Angle (2θ1/2): 100 degrees (Typ.). The full angle at which the radiant intensity is half the on-axis intensity. A wider angle makes alignment between emitter and detector less critical.

3. Performance Curve Analysis

The datasheet provides several characteristic curves that are essential for understanding device behavior under varying conditions. These graphs allow designers to extrapolate performance beyond the single-point specifications.

3.1 Spectral Distribution

The spectral distribution curve shows the relative radiant intensity as a function of wavelength. For this device, the curve is centered around 850nm with the defined 50nm half-width. This information is critical for selecting compatible optical filters for the detector side to reject ambient light noise.

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

This curve illustrates the non-linear relationship between the current through the IRED and the voltage across it. It shows the typical turn-on voltage and how VF increases with IF. Designers use this to calculate the necessary series resistor value for current limiting when driven from a voltage source.

3.3 Forward Current vs. Ambient Temperature

This graph demonstrates how the maximum allowable DC forward current derates as the ambient temperature increases. To ensure reliability, the operating current must be reduced at higher temperatures to keep the junction temperature and power dissipation within safe limits.

3.4 Relative Radiant Intensity vs. Ambient Temperature

This curve shows the dependence of optical output power on temperature. Typically, the radiant intensity decreases as the junction temperature rises. This characteristic must be accounted for in applications requiring stable optical output over a wide temperature range.

3.5 Relative Radiant Intensity vs. Forward Current

This is a key curve showing the optical output power as a function of drive current. It is generally linear over a significant range but may saturate at very high currents. Designers use this to determine the required drive current to achieve a specific signal strength.

3.6 Radiation Pattern Diagram

A polar plot depicting the spatial distribution of emitted light. The diagram confirms the wide 100-degree viewing angle, showing how intensity diminishes at angles off the central axis. This pattern is crucial for designing the optical path and alignment in a system.

4. Mechanical and Packaging Information

4.1 Outline and Package Dimensions

The device uses a standard 1206 SMD package. Key dimensions include a body length of approximately 3.2mm, a width of 1.6mm, and a height of 1.1mm. The datasheet provides a detailed dimensional drawing with tolerances typically at ±0.1mm. The cathode is typically indicated by a marking or a specific pad geometry.

4.2 Suggested Soldering Pad Layout

A recommended land pattern (footprint) for PCB design is provided. This includes the pad dimensions, spacing, and shape to ensure a reliable solder joint during reflow while minimizing the risk of tombstoning or solder bridging. Adhering to these recommendations is important for manufacturing yield.

4.3 Tape and Reel Packaging Specifications

The components are supplied in embossed carrier tape wound on 7-inch (178mm) diameter reels. Key tape dimensions include pocket pitch, pocket size, and tape width. Each reel contains 3000 pieces. The packaging conforms to ANSI/EIA 481-1-A-1994 standards, ensuring compatibility with standard automated feeders.

5. Assembly, Handling, and Application Guidelines

5.1 Soldering and Reflow Process

The device is compatible with infrared reflow soldering processes. A detailed reflow temperature profile is suggested, compliant with JEDEC standards for lead-free assembly. Key parameters include:

• Pre-heat: 150-200°C for up to 120 seconds maximum.
• Peak Temperature: 260°C maximum.
• Time Above Liquidus: The component should not be exposed to temperatures above 260°C for more than 10 seconds, and reflow should not be performed more than twice.

For hand soldering with an iron, the recommendation is a maximum tip temperature of 300°C for no more than 3 seconds per joint. It is emphasized that the optimal profile depends on the specific PCB design, solder paste, and oven, so process characterization is necessary.

5.2 Storage and Moisture Sensitivity

The components are moisture-sensitive. In their original sealed moisture-proof bag with desiccant, they should be stored at ≤30°C and ≤90% Relative Humidity (RH) and used within one year. Once the bag is opened, the storage environment must not exceed 30°C / 60% RH. Components removed from the original packaging should be reflowed within one week. For longer storage outside the original bag, they must be stored in a sealed container with desiccant or in a nitrogen desiccator. Components stored unpackaged for over a week require baking (e.g., at 60°C for 20 hours) before soldering to remove absorbed moisture and prevent "popcorning" during reflow.

5.3 Cleaning

If cleaning is required after soldering, only alcohol-based solvents like isopropyl alcohol (IPA) should be used. Harsh or aggressive chemical cleaners should be avoided as they may damage the epoxy lens of the package.

5.4 Drive Method and Circuit Design

A critical design note is that an LED is a current-operated device. When driving the IR emitter, a series current-limiting resistor is mandatory when using a voltage source. This resistor sets the operating current (IF) to the desired value, calculated using Ohm's Law: R = (Vcc - VF) / IF. Furthermore, when multiple emitters are connected in parallel, a separate current-limiting resistor should be used for each device to ensure intensity uniformity, as the forward voltage (VF) can vary slightly from unit to unit.

5.5 Application Cautions and Intended Use

The component is intended for general-purpose electronic equipment. For applications requiring exceptional reliability where failure could jeopardize life or health (e.g., aviation, medical, transportation safety systems), specific consultation and qualification are required, as these are beyond the scope of standard commercial-grade specifications provided in this datasheet.

6. Technical Comparison and Design Considerations

Compared to simple discrete IREDs or photodetectors, this integrated emitter-detector pair in a single package offers design simplification by ensuring matched optical characteristics and close physical proximity, which can be beneficial for reflective sensing. The 850nm wavelength is less visible to the human eye than 940nm, making it suitable for applications where a faint red glow is acceptable or even used as a status indicator. The 100-degree viewing angle is notably wide, reducing alignment precision requirements compared to narrower-beam devices.

Designers must carefully consider the trade-off between drive current, radiant intensity, and device lifetime/heat generation. Operating at or near the absolute maximum ratings for current or temperature will accelerate aging and reduce long-term reliability. Adequate PCB layout for heat dissipation, especially if operating at high duty cycles or elevated ambient temperatures, is recommended.

7. Frequently Asked Questions (Based on Technical Parameters)

Q: Can I drive this IRED directly from a microcontroller GPIO pin?

A: No. A microcontroller pin typically cannot source 20-60mA safely. You must use the GPIO to control a transistor (e.g., MOSFET or BJT) that switches the higher current from a power supply, with a series resistor to set the exact current.

Q: What is the difference between peak wavelength (λp) and dominant wavelength (λd)?

A> Peak wavelength is the point of maximum spectral power. Dominant wavelength is derived from color perception on a chromaticity diagram and represents a single wavelength that matches the perceived color. For monochromatic IR devices, they are often very close.

Q: How do I interface with the detector side of this component?

A> The datasheet primarily details the emitter characteristics. The detector (photodiode or phototransistor) will have its own set of parameters (dark current, responsivity, etc.) not fully listed here. Typically, the detector output is a small current proportional to received IR light, which is usually converted to a voltage using a transimpedance amplifier or a simple load resistor for digital threshold detection.

Q: Why is the storage humidity condition so important?

A> SMD packages can absorb moisture through the plastic molding compound. During the high heat of reflow soldering, this trapped moisture can vaporize rapidly, creating internal pressure that can crack the package or delaminate internal bonds—a failure known as "popcorning." The storage and baking guidelines prevent this.

8. Practical Application Example

Design Case: Simple Proximity/Obstruction Sensor

A common use is a beam-break sensor. The emitter is driven with a pulsed current (e.g., 20mA pulses at 38kHz) to distinguish its signal from ambient IR. The detector, placed a short distance away, receives this signal. When an object interrupts the beam, the received signal drops. The detector's output is fed into a demodulating receiver IC or a microcontroller with filtering logic to detect the absence of the carrier frequency, triggering an output. The wide viewing angle simplifies aligning the emitter and detector on opposite sides of the path being monitored.

9. Operational Principle

The device operates on fundamental optoelectronic principles. The emitter is an Infrared Emitting Diode (IRED). When forward-biased, electrons and holes recombine in the semiconductor's active region (GaAs/AlGaAs), releasing energy in the form of photons. The material's bandgap determines the photon energy and thus the wavelength, which is 850nm in this case. The detector is typically a photodiode or phototransistor made of silicon. When photons with sufficient energy (wavelengths typically up to ~1100nm for silicon) strike the detector's depletion region, they generate electron-hole pairs. In a photodiode, this creates a photocurrent when reverse-biased. In a phototransistor, the photocurrent acts as a base current, causing a larger collector current to flow, providing internal gain.

10. Technology Trends

In the field of discrete infrared components, trends include the development of devices with higher power output for longer range, improved speed for faster data transmission, and enhanced spectral filtering integrated into the detector package to achieve higher signal-to-noise ratios in environments with strong ambient light. There is also a move towards miniaturization beyond the 1206 package (e.g., 0805, 0603) to save board space, though often at the expense of optical power or viewing angle. The drive for higher reliability and performance in automotive and industrial applications continues to push the development of components with wider operating temperature ranges and more robust packaging.