QED123 Infrared (IR) LED Emitter -- 880nm AlGaAs, Narrow Beam, High Power – onsemi
The QED123 is a high-output infrared LED emitter manufactured by onsemi (formerly ON Semiconductor). Built with AlGaAs (Aluminum Gallium Arsenide) chip technology and encapsulated in a clear peach-tinted T-1 3/4 (5mm) package, it emits powerful infrared light at a peak wavelength of 880nm -- invisible to the human eye but easily detected by silicon phototransistors and photodiodes.
With a narrow 16° emission angle and 70 mW/sr typical radiant intensity at 100 mA, the QED123 delivers a tightly focused, high-power IR beam ideal for long-range detection, optical communication, and precision sensing applications. When paired with a matched QSD124 phototransistor (sold separately), it forms a complete IR transmitter/receiver pair optimized for maximum coupling efficiency at 880nm.
Key Features
- Peak Emission Wavelength: 880nm (near-infrared, invisible to the human eye)
- High Radiant Intensity: 70 mW/sr typical at 100 mA -- strong, focused IR output
- Narrow Emission Angle: 16° for precise, directional beam control
- Fast Switching: 900 ns rise time, 800 ns fall time -- suitable for modulated/pulsed IR
- AlGaAs Chip Technology: Superior efficiency vs. standard GaAs IR LEDs
- Wide Operating Range: -40°C to +100°C
- Standard T-1 3/4 (5mm) Package: Easy breadboard and through-hole PCB mounting
- Continuous Forward Current: Up to 100 mA
- Matched Detectors: Designed to pair with QSD123/QSD124 phototransistors
- Pb-Free / RoHS Compliant
Specifications
| Manufacturer |
onsemi (formerly ON Semiconductor) |
| Part Number |
QED123 |
| Peak Emission Wavelength |
890 nm (typ) |
| Emission Angle |
16° |
| Radiant Intensity (typ / min) |
70 mW/sr (typ), 50 mW/sr (min) at IF = 100 mA |
| Forward Voltage (max) |
1.7V |
| Continuous Forward Current (max) |
100 mA |
| Reverse Voltage (max) |
5V |
| Reverse Current (max) |
10 µA |
| Rise / Fall Time (typ) |
900 ns / 800 ns |
| Junction Capacitance (typ) |
11 pF |
| Power Dissipation |
200 mW (derate 2.67 mW/°C above 25°C) |
| Operating Temperature |
-40°C to +100°C |
| Package |
T-1 3/4, 5mm Through-Hole Radial (Case 100CC) |
| Package Material |
Clear, Peach Tinted Plastic |
| Chip Material |
AlGaAs (Aluminum Gallium Arsenide) |
| RoHS / Pb-Free |
Yes |
Test conditions: IF = 100 mA, tp = 20 ms, TA = 25°C unless otherwise noted.
Pin Identification
| Longer Lead |
Anode (+) |
| Shorter Lead |
Cathode (−) |
| Flat on Package Base |
Indicates Cathode side |
The QED123 is a polarized component. Reversing polarity will prevent emission and may cause damage if reverse voltage exceeds 5V.
Typical Circuit -- Basic IR Emitter
Connect the QED123 in series with a current-limiting resistor:
VCC ──── R (current limiting) ──── QED123 Anode (+) ──── QED123 Cathode (−) ──── GND
Current-Limiting Resistor Selection: R = (VCC − VF) / IF
| Supply Voltage |
Target Current |
Resistor |
Output |
| 3.3V |
20 mA |
82 Ω |
~20 mW/sr (reduced) |
| 5V |
50 mA |
68 Ω |
~45 mW/sr |
| 5V |
100 mA |
33 Ω |
~70 mW/sr (max) |
| 12V |
100 mA |
100 Ω |
~70 mW/sr (max) |
💡 Tip: Most microcontroller GPIO pins can only source 20–40 mA. To drive the QED123 at full 100 mA, use an NPN transistor or N-channel MOSFET as a switch between your GPIO pin and the LED circuit.
Matched Emitter / Detector Pair
The QED123 is specifically designed to work with onsemi's QSD12X phototransistor family:
| Emitter |
Detector |
Pairing Notes |
| QED123 (this listing) |
QSD123 |
Standard sensitivity detector |
| QED123 (this listing) |
QSD124 |
High sensitivity -- recommended for longest range |
Why use a matched pair? The QED123 emits at 880nm -- the exact peak sensitivity wavelength of the QSD123/QSD124. The QSD124's built-in daylight filter blocks visible light while passing the QED123's emission, maximizing signal-to-noise ratio and detection range.
Common Applications
- Object / presence detection (paired with QSD124 detector)
- Optical counters -- items on conveyor or production line
- Proximity sensors -- reflected IR detection
- Optical encoders -- rotary and linear position sensing
- Optical switches / interrupters
- IR remote control transmitters
- Line-following robots -- surface reflectance sensing
- Wireless IR communication -- short-range data transmission
- Tachometers / RPM counters
- Security systems -- IR beam break perimeter monitoring
What's in the Box
- 1x, 2x, 5x, or 10x QED123 Infrared LED Emitters (onsemi) - Quantity chosen above
⚠️ Matched detector sold separately. The QSD124 IR phototransistor is the recommended paired detector for this emitter. Visit our eBay Store for availability.
Important Notes
- Polarity matters. The QED123 is a diode -- it only conducts in one direction. Identify the flat on the package base (cathode side) before soldering. Do not exceed 5V reverse voltage.
- Always use a current-limiting resistor. Connecting the QED123 directly to a voltage source without a resistor will destroy it instantly.
- Do not exceed 100 mA continuous forward current or 200 mW power dissipation (derate at 2.67 mW/°C above 25°C).
- IR light is invisible. You cannot see the QED123's output with the naked eye. Use a smartphone camera (most can detect near-IR) to verify the LED is emitting, or use a phototransistor/photodiode test circuit.
- Soldering: Use RMA flux. Keep iron tip at least 1.6mm from housing. Iron: 240°C max for 5 seconds. Flow: 260°C max for 10 seconds.
- Temperature affects output. Radiant intensity decreases ~0.3%/°C. At 85°C, output is roughly 82% of the 25°C value.
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