IR Emitter and Detector LTE-C9501-E-T Datasheet - 940nm Peak Wavelength - 20 Degree Viewing Angle - English Technical Document

1. Product Overview

This document details the specifications for a discrete infrared (IR) component designed for surface-mount applications. The device combines an infrared emitter and detector functionality, targeting solutions requiring reliable IR signal transmission and reception. Its core advantages include compatibility with automated assembly processes, adherence to RoHS and green product standards, and suitability for high-volume manufacturing via infrared reflow soldering. The primary target markets include consumer electronics for remote control systems, industrial applications for wireless data transmission, and security systems for alarm and sensing functions.

2. Technical Specifications Deep Dive

2.1 Absolute Maximum Ratings

All ratings are specified at an ambient temperature (TA) of 25°C. Exceeding these limits may cause permanent damage.

• Power Dissipation (Pd): 100 mW maximum.
• Peak Forward Current (IFP): 800 mA maximum under pulsed conditions (300 pps, 10 μs pulse width).
• DC Forward Current (IF): 60 mA maximum continuous current.
• Reverse Voltage (VR): 5 V maximum.
• Operating Temperature Range (Topr): -40°C to +85°C.
• Storage Temperature Range (Tstg): -55°C to +100°C.
• Infrared Soldering Condition: Maximum peak temperature of 260°C for 10 seconds.

2.2 Electrical and Optical Characteristics

Typical performance is measured at TA=25°C unless otherwise noted.

• Radiant Intensity (I_E): Ranges from 1.0 to 6.0 mW/sr at a forward current (I_F) of 20mA. The exact value is determined by the bin code.
• Peak Emission Wavelength (λ_p): 940 nm (typical). This wavelength is in the near-infrared spectrum, invisible to the human eye, making it ideal for remote controls and data links.
• Spectral Line Half-Width (Δλ): 50 nm (typical). This parameter defines the spectral bandwidth of the emitted IR light.
• Forward Voltage (V_F): 1.2V typical, with a range of 1.1V to 1.5V at I_F=20mA.
• Reverse Current (I_R): 10 μA maximum at a reverse voltage (V_R) of 5V.
• Viewing Angle (2θ_1/2): 20 degrees. This is the full angle at which the radiant intensity is half the value at the central axis (0°). A narrower viewing angle results in more directed radiation.

3. Binning System Explanation

The devices are sorted into bins based on their measured radiant intensity at the standard test condition of I_F=20mA. This allows designers to select components with consistent optical output for their application.

• BIN A: Radiant Intensity from 1.0 mW/sr (Min) to 2.0 mW/sr (Max).
• BIN B: Radiant Intensity from 2.0 mW/sr (Min) to 3.0 mW/sr (Max).
• BIN C: Radiant Intensity from 3.0 mW/sr (Min) to 6.0 mW/sr (Max).

A tolerance of +/-15% applies to the intensity within each bin. No separate binning for wavelength or forward voltage is indicated in this datasheet.

4. Performance Curve Analysis

The datasheet provides several characteristic graphs essential for circuit design and understanding device behavior under varying conditions.

4.1 Spectral Distribution

Figure 1 shows the relative radiant intensity versus wavelength. The curve is centered at 940 nm with a typical half-width of 50 nm, confirming the spectral purity of the emitted infrared light.

4.2 Forward Current vs. Ambient Temperature

Figure 2 illustrates the derating of the maximum allowable forward current as the ambient temperature increases. The current rating decreases linearly from its maximum value at lower temperatures to zero at the maximum junction temperature, ensuring reliable operation by preventing thermal overload.

4.3 Forward Current vs. Forward Voltage

Figure 3 depicts the IV (Current-Voltage) characteristic curve. It shows the exponential relationship typical of a diode, with the forward voltage being relatively constant (around 1.2V) over a wide range of operating currents.

4.4 Relative Radiant Intensity vs. Ambient Temperature and Forward Current

Figures 4 and 5 show how the optical output power changes with temperature and drive current. Output typically decreases as temperature rises (Figure 4) and increases super-linearly with forward current (Figure 5), highlighting the importance of stable drive current and thermal management for consistent performance.

4.5 Radiation Pattern

Figure 6 is a polar radiation diagram showing the spatial distribution of emitted light. The pattern confirms the 20-degree viewing angle, with intensity dropping to 50% at +/-10 degrees from the center axis.

5. Mechanical and Package Information

5.1 Outline Dimensions

The component is housed in a standard EIA package. The exact dimensions are provided in the datasheet drawings, with a general tolerance of ±0.1mm unless otherwise specified. The package features a water-clear plastic lens with a top-view configuration.

5.2 Recommended Solder Pad Layout

A suggested land pattern for PCB design is provided, with dimensions of 1.0mm x 1.8mm for the pads. This layout is optimized for reliable soldering and mechanical stability during the reflow process.

5.3 Polarity Identification

Standard diode polarity markings apply. The cathode is typically indicated on the package. Designers must consult the detailed outline drawing for the exact marking scheme to ensure correct orientation during assembly.

6. Soldering and Assembly Guidelines

6.1 Reflow Soldering Profile

A suggested infrared reflow profile for lead-free (Pb-free) processes is included. Key parameters include:

• Pre-heat: 150-200°C.
• Pre-heat Time: Maximum 120 seconds.
• Peak Temperature: Maximum 260°C.
• Time Above Liquidus: Maximum 10 seconds (recommended for a maximum of two reflow cycles).

The profile is based on JEDEC standards to ensure component reliability. The datasheet emphasizes that the optimal profile depends on the specific PCB design, solder paste, and oven, so board-level characterization is advised.

6.2 Hand Soldering

If hand soldering is necessary, use a soldering iron at a maximum temperature of 300°C for no more than 3 seconds per joint. Avoid applying excessive mechanical stress to the component.

6.3 Storage Conditions

Proper storage is critical for solderability:

• Sealed Package: Store at ≤30°C and ≤90% RH. Use within one year of opening the moisture barrier bag.
• Opened Package: Store at ≤30°C and ≤60% RH. Components should be reflowed within one week. For longer storage, use a sealed container with desiccant or a nitrogen atmosphere. Components stored out of the original bag for more than one week require baking at approximately 60°C for at least 20 hours before soldering.

6.4 Cleaning

If cleaning is required after soldering, use only alcohol-based solvents such as isopropyl alcohol. Avoid using aggressive or aqueous cleaners that may damage the plastic package or lens.

7. Packaging and Ordering Information

7.1 Tape and Reel Specifications

The component is supplied in 8mm carrier tape on 7-inch diameter reels, compatible with standard automatic pick-and-place equipment. Each reel contains 2000 pieces. The packaging conforms to ANSI/EIA 481-1-A-1994 standards.

7.2 Model Number Breakdown

The part number LTE-C9501-E-T identifies this specific variant. The "E" and "T" suffixes likely denote specific binning, packaging (Tape & Reel), or other product variations as per the manufacturer's internal coding system.

8. Application Recommendations

8.1 Typical Application Circuits

The IR emitter is typically driven by a transistor or a dedicated driver IC to provide the necessary pulsed current (e.g., for remote control codes). A series current-limiting resistor is mandatory to set the forward current (I_F) to the desired value, calculated using (Supply Voltage - V_F) / I_F. The detector side, if a photodiode or phototransistor is integrated, would be connected in a reverse-biased configuration with a load resistor to convert the photocurrent into a measurable voltage.

8.2 Design Considerations

• Current Drive: Operate within the Absolute Maximum Ratings. For continuous operation, do not exceed 60mA DC. For pulsed operation (like remote controls), higher peak currents up to 800mA are permissible, which significantly increases the instantaneous radiant output and transmission range.
• Thermal Management: The power dissipation rating of 100mW must be respected. On a PCB, ensure adequate copper area around the pads to act as a heat sink, especially when operating near maximum ratings.
• Optical Path: The 20-degree viewing angle is relatively narrow. Align the emitter and detector precisely. Avoid obstructions and consider the use of lenses or light pipes if a different beam pattern is required.
• Ambient Light Rejection: For detector applications, the 940nm peak sensitivity helps reject visible light noise. For environments with strong IR sources (like sunlight or incandescent bulbs), additional optical filtering or modulated (AC-coupled) signal detection techniques may be necessary to improve the signal-to-noise ratio.

9. Technical Comparison and Differentiation

Compared to generic IR LEDs, this component offers specific advantages: its compatibility with automatic placement and IR reflow soldering streamlines high-volume manufacturing. The availability in intensity bins (A, B, C) allows for design consistency. The 940nm wavelength is a common standard for consumer remote controls, ensuring compatibility with a wide range of receivers. The inclusion of detailed soldering profiles and storage guidelines demonstrates a design-for-manufacturability focus.

10. Frequently Asked Questions (FAQ)

Q: What is the difference between Radiant Intensity (mW/sr) and Luminous Intensity (mcd)?
A: Radiant Intensity measures the total optical power emitted per solid angle, relevant for IR devices. Luminous Intensity measures perceived brightness by the human eye, weighted by the photopic response curve, and is used for visible LEDs. For this IR device, Radiant Intensity is the correct metric.

Q: Can I use this for continuous data transmission?
A: Yes, but you must operate within the DC forward current limit of 60mA. For higher-speed or longer-distance transmission, pulsed operation (within the 800mA peak rating) is more effective, as it allows for higher instantaneous optical power.

Q: How do I select the correct BIN?
A: Choose based on the required optical power for your link budget. BIN C (3-6 mW/sr) provides the highest output and longest range. BIN A or B may be sufficient for short-range applications and can be more cost-effective.

Q: Is an external lens needed?
A: The device has an integrated top-view lens providing a 20-degree beam. An external lens is typically not needed unless you require beam collimation (narrower angle) or focusing.

11. Practical Design Case Study

Scenario: Designing a simple IR remote control transmitter for a home appliance.
Design Steps:
1. Component Selection: Choose this IR emitter (e.g., BIN C for good range).
2. Drive Circuit: Use a microcontroller GPIO pin to generate the modulated carrier signal (e.g., 38kHz). This signal drives a transistor (e.g., NPN) in a switch configuration. The collector of the transistor is connected to the IR emitter's anode, and the cathode is connected to ground. A resistor in series with the emitter sets the current: R = (Vcc - V_CE(sat) - V_F) / I_F. Assuming Vcc=3.3V, V_CE(sat)=0.2V, V_F=1.2V, and desired I_F=100mA (pulsed), R = (3.3 - 0.2 - 1.2) / 0.1 = 19Ω (use a standard 20Ω resistor). Ensure the transistor can handle the peak current.
3. PCB Layout: Place the emitter at the edge of the PCB. Use the recommended solder pad dimensions. Provide a small copper pour for heat dissipation.
4. Testing: Verify the output using an IR receiver module or a digital camera (which can see the 940nm light as a faint purple glow).

12. Operating Principle

The device operates on the principle of electroluminescence for the emitter section. When a forward current is applied to the semiconductor chip (likely GaAs-based for 940nm emission), electrons and holes recombine in the active region, releasing energy in the form of photons (light) at a wavelength corresponding to the bandgap energy of the material (940nm). The detector section, if present, operates on the principle of the photoelectric effect. Incident infrared photons with sufficient energy create electron-hole pairs in the semiconductor, generating a photocurrent when a reverse bias voltage is applied. This current is proportional to the intensity of the incoming IR light.

13. Industry Trends

The market for discrete IR components remains stable, driven by established applications like remote controls, proximity sensing, and optical switches. Trends include the integration of IR emitters and detectors into more complex modules with built-in drivers and logic (e.g., proximity sensor modules with I2C output). There is also a continuous push for higher efficiency (more radiant output per mA of drive current) and smaller package sizes to fit into increasingly compact consumer devices. The emphasis on RoHS compliance and green manufacturing, as seen in this datasheet, is a universal industry standard.