Infrared LED E35S9 850nm - Size 3.5x3.5x2.29mm - Forward Current 1000mA - Power 1.8W - Technical Datasheet

1. Product Overview

This infrared LED is designed for high-reliability applications requiring a compact, high-power infrared emitter. It features an EMC (Epoxy Molding Compound) package with dimensions of 3.50 mm × 3.50 mm × 2.29 mm, making it suitable for space-constrained designs. The device emits at a peak wavelength of 850 nm, which is widely used in security monitoring, machine vision, and IR illumination systems. Key advantages include low forward voltage, Pb-free reflow soldering compatibility, moisture sensitivity level 3, and RoHS compliance.

2. Technical Parameters Interpretation

2.1 Optical and Electrical Characteristics

At a forward current of 1000 mA (pulsed condition), the typical forward voltage is 1.7 V, with a minimum of 1.5 V. The reverse current at 5 V is limited to 10 µA maximum. The peak wavelength is centered at 850 nm (830 nm min, 850 nm typ) with a spectral bandwidth of 45 nm. Total radiant flux is typically 950 mW, ranging from 710 mW to 1120 mW. The half-intensity viewing angle is 90°, providing wide coverage for illumination applications.

2.2 Absolute Maximum Ratings

The device can handle a maximum power dissipation of 1.8 W and a forward current of 1000 mA (1/10 duty cycle, 0.1 ms pulse width). Reverse voltage is limited to 5 V. ESD sensitivity is 2000 V (HBM). Operating temperature range is -40 °C to +85 °C, storage from -40 °C to +100 °C, and junction temperature up to 105 °C. Thermal resistance from junction to solder point is 11 °C/W.

2.3 Binning System

The product is binned by total radiant flux (Φe), peak wavelength (WLP), and forward voltage (VF), as indicated on the label. This allows customers to select devices with tightly controlled parameters for consistent system performance. Binning ensures that all LEDs in a batch meet specific photometric and electrical specifications.

3. Performance Curve Analysis

3.1 Forward Voltage vs. Forward Current

As shown in Fig 1-6, forward current increases exponentially with forward voltage above the knee at approximately 1.4 V. At 1.6 V, current reaches around 800 mA; at 1.7 V it reaches 1000 mA. This relationship is typical for infrared LEDs and highlights the need for precise current regulation.

3.2 Relative Intensity vs. Forward Current

Fig 1-7 demonstrates that relative intensity increases almost linearly with forward current up to 1000 mA, with saturation beginning above 800 mA. For maximum efficiency, driving at around 800 mA is recommended.

3.3 Temperature Dependence

Fig 1-8 shows that relative intensity decreases with rising solder temperature (Ts). At 85 °C, intensity drops to about 80% of the value at 25 °C; at 105 °C it falls to 70%. Thermal management is critical to maintain output.

3.4 Spectral Distribution

The emission spectrum (Fig 1-9) peaks at 850 nm with a FWHM of 45 nm. The spectrum is Gaussian-like, with negligible emission below 700 nm and above 1000 nm. This narrow band is ideal for filtering and matching with silicon detectors.

3.5 Radiation Pattern

The radiation diagram (Fig 1-10) shows a Lambertian-like pattern with half-power angle of ±45°, giving a total viewing angle of 90°. This provides uniform illumination over a wide area, suitable for CCTV and camera systems.

3.6 Maximum Forward Current vs. Temperature

Fig 1-11 indicates that the maximum allowable forward current decreases linearly above 25 °C, from 1000 mA at 25 °C to approximately 300 mA at 100 °C. Derating is necessary for high-temperature operation.

4. Mechanical Packaging Information

4.1 Package Dimensions

The top view shows a 3.50 mm square package. Side view height is 2.29 mm. Bottom view reveals two large pads: cathode pad (2.62 mm × 2.44 mm) and anode pad (2.62 mm × 0.62 mm), with a central thermal pad (1.60 mm × 0.50 mm). Soldering patterns (Fig 1-5) indicate recommended PCB land patterns. Polarity is marked on the package: cathode indicated by a notch or symbol.

4.2 Tape and Reel

Carrier tape has 12.00 mm width, 4.00 mm pitch, with a polarity mark. Reel dimensions: A (12.7±0.3 mm), B (330.2±2 mm), C (79.5±1 mm), D (14.3±0.2 mm). Each reel contains 3000 pieces.

4.3 Label Information

Labels include Part Number, Spec Number, Lot Number, Bin Code, Quantity, Date, and binned values for Φe, WLP, and VF. This ensures traceability and binning control.

5. Soldering and Assembly Guide

5.1 Reflow Soldering Profile

The recommended reflow profile is described in Table 3-1 and Fig 3-1. Key parameters: preheat at 150-200 °C for 60-120 s; time above 217 °C (TL) is 60-150 s; peak temperature (TP) 260 °C with a hold time of 10 s maximum. Ramp-up rate is ≤3 °C/s, ramp-down ≤6 °C/s. Reflow should be done no more than twice.

5.2 Hand Soldering and Repair

Hand soldering: iron temperature below 300 °C for less than 3 seconds, one time only. Repair with a double-head soldering iron is possible but must be confirmed not to damage the LED. Avoid pressure on the silicone encapsulant.

5.3 Cautionary Notes

Do not mount components on warped PCB. Avoid mechanical stress during cooling. Do not rapidly cool after soldering. The silicone encapsulant is soft; handle with care. Use appropriate pick-and-place nozzle pressure.

6. Storage and Handling Precautions

6.1 Storage Conditions

Before opening the aluminum bag: store at ≤30 °C and ≤75% RH for up to 1 year from date of manufacture. After opening: ≤30 °C and ≤60% RH for 168 hours. If moisture indicator changes or storage time exceeded, baking at 60±5 °C for 24 hours is required. If bag is damaged, contact sales.

6.2 Handling Precautions

Sulfur content in mating materials should not exceed 100 ppm. Bromine and Chlorine each <900 ppm, total <1500 ppm. VOCs from fixture materials can discolor silicone; use compatible materials. Handle by side surfaces; do not touch silicone lens directly. ESD protection is required (ESD sensitivity level 2 kV). Proper circuit design with current limiting resistors is mandatory. Thermal design is critical: ensure heat dissipation to keep junction temperature below 105 °C. Cleaning with isopropyl alcohol is recommended; ultrasonic cleaning may cause damage.

7. Package and Ordering Information

Standard packaging: 3000 pieces per reel. The part number is RF-E35S9-IRB-FR. Each reel is sealed in a moisture barrier bag with desiccant and humidity indicator. Outer cardboard box contains multiple reels. Refer to label for specific bin codes.

8. Application Suggestions

8.1 Typical Applications

• Surveillance systems: IR illumination for CCTV cameras.
• Infrared illumination for cameras (night vision).
• Machine vision systems: industrial inspection, barcode scanners.
• Sensors: proximity, motion detection.

8.2 Design Considerations

Use appropriate current limiting resistors to maintain IF below 1000 mA. Implement good thermal management: large copper pads, thermal vias, heat sinks. Consider pulse operation for higher peak current with low duty cycle. Keep traces short to reduce inductance. Shield from ambient light if using with high-sensitivity detectors.

9. Technical Comparison

Compared to standard 5mm through-hole IR LEDs, this SMD EMC package offers lower profile, higher power handling, and better thermal performance. Integrated EMC package provides robust mechanical strength and moisture resistance. The 850 nm wavelength is superior to 940 nm for many vision systems due to better silicon sensor response. Wide 90° viewing angle simplifies optical design.

10. Frequently Asked Questions

Q: Can I drive this LED at 1000 mA DC?

No, the 1000 mA rating is for pulsed operation with 1/10 duty cycle and 0.1 ms pulse width. DC operation must be derated significantly (max ~300 mA at 25°C).

Q: What is the typical lifespan?

Lifespan depends on thermal management; typical L70 life is >50,000 hours at rated conditions with proper heatsinking.

Q: How to clean the LED?

Use isopropyl alcohol. Do not use ultrasonic cleaning.

Q: Is the device RoHS compliant?

Yes, it is RoHS compliant as stated in features.

11. Practical Application Example

In a typical IP camera module, four E35S9 LEDs are arranged around the lens at a distance of 20 mm. Using a 1.5 V forward voltage, a current limiting resistor of 0.2 Ω is used for each LED in series with a 12 V supply, but careful calculation based on pulse current is required. The total illumination pattern achieves even coverage for distances up to 15 meters. Thermal design includes an aluminum heatsink and thermal interface material.

12. Operating Principle

This infrared LED operates by electroluminescence in a semiconductor diode. When forward biased, electrons and holes recombine in the active region (likely AlGaAs or GaAs material for 850 nm), emitting photons in the near-infrared spectrum. The EMC package encapsulates the chip and provides mechanical protection and good thermal conduction.

13. Development Trends

Infrared LED technology is moving towards higher efficiency and higher power densities. Packages like the EMC with enhanced thermal management allow for higher forward currents. Wavelengths around 850 nm remain standard for silicon-based detectors. Integration with optics (lenses, reflectors) in a single package is becoming more common. Future trends include improved reliability under harsh environments and even smaller footprints.