Light-Emitting Diodes (LEDs) – Standard, High-Power, SMD, RGB, and IR Types

Light-emitting diodes have evolved from simple panel indicators into the dominant illumination technology of the twenty-first century. LEDs convert electrical current directly into photons through electroluminescence in a semiconductor junction, achieving luminous efficacies exceeding 200 lumens per watt — far surpassing incandescent and fluorescent sources. ADD Components supplies LEDs across the full application spectrum, sourcing from Osram, Cree LED, Vishay, and Broadcom to meet procurement requirements from prototype to production volumes.

Sub-Types and Categories

Standard Through-Hole LEDs

Standard LEDs in 3 mm (T-1), 5 mm (T-1¾), and 8 mm through-hole packages remain the workhorse for front-panel indication, status signalling, and educational electronics. These devices typically deliver 2–50 millicandelas of luminous intensity from a forward current of 10–20 mA, with forward voltages of 1.8–3.6 V depending on colour chemistry. Wavelengths span from deep red (660 nm) through to blue (470 nm) using AlGaAs, AlInGaP, and InGaN semiconductor alloys. Vishay's TLx and TLLx series provide industry-standard 5 mm LEDs with wide viewing angles and consistent colour binning, while Osram's TOPLED through-hole range offers enhanced brightness for outdoor-readable applications. Through-hole LEDs remain essential for legacy product maintenance, harsh-environment designs, and applications where manual assembly is preferred.

High-Power LEDs

High-power LEDs operate at drive currents from 350 mA to several amperes, delivering 100 to over 1000 lumens from a single package. Thermal management becomes the dominant design consideration — junction temperatures must remain below 125°C to 150°C, requiring metal-core PCBs, heat sinks, and sometimes active cooling. Cree LED's XLamp series (including XHP and XP-G families) set industry benchmarks for efficacy and reliability in general illumination, while Osram's OSLON family targets automotive forward lighting and horticultural applications. Lumileds LUXEON devices offer compact high-density sources for street lighting and industrial high-bay fixtures. Procurement teams should specify exact CCT (correlated colour temperature), CRI (colour rendering index), and flux binning codes when ordering to ensure batch-to-batch consistency in production.

SMD LEDs

Surface-mount device LEDs have become the dominant format for automated PCB assembly, available in footprints from 0201 and 0402 chip-scale packages through to larger 5050 and 5630 packages for higher output. SMD LEDs cover applications from LCD backlighting and mobile keypads through to automotive interior lighting and consumer appliance indicators. Key package families include 0603 (1.6 mm x 0.8 mm), 0805 (2.0 mm x 1.25 mm), and 1206 (3.2 mm x 1.6 mm) sizes, with reverse-mount configurations available for light-guide coupling. Osram's Firefly and Micro SIDELED series provide ultra-compact solutions for portable electronics, while Vishay's VLMW and VLMS series deliver AEC-Q101 qualified SMD LEDs for automotive applications. When selecting SMD LEDs, consider luminous intensity, viewing angle, binning tolerance, and solder-joint reliability under thermal cycling.

RGB and Multi-Colour LEDs

RGB LEDs integrate red, green, and blue emitters into a single package, enabling full-colour mixing through independent current control of each channel. Common-anode and common-cathode configurations simplify driver design, while addressable RGB LEDs embed serial communication controllers for daisy-chained pixel arrays in decorative and display lighting. Osram's DISPLIX and MULTILED series provide high-brightness multi-colour solutions for video walls, architectural lighting, and automotive ambient illumination. Four-pin through-hole RGB LEDs in 5 mm packages remain popular for prototyping, while compact SMD versions serve professional applications requiring colour-changing status indication. For precision colour applications, designers should consult chromaticity coordinates and binning data to maintain consistent visual appearance across production volumes.

Infrared (IR) LEDs

Infrared LEDs emit at wavelengths beyond the visible spectrum — typically 850 nm, 880 nm, or 940 nm — and serve as the companion emitter to photodiodes and phototransistors in optical sensing systems. The 850 nm wavelength offers a faint visible red glow useful for alignment verification, while 940 nm provides completely covert operation for security cameras and presence detection. IR LEDs are essential in remote controls, proximity sensors, light curtains, night-vision illumination, and optical encoders. Vishay's TSAL and VSMY series dominate the IR emitter market with devices offering radiant intensities from 10 mW/sr to over 500 mW/sr in narrow-beam configurations. Osram's SFH series provides high-speed IR emitters with rise times below 15 ns for data transmission. Key specifications include peak wavelength, radiant intensity, half-angle, and maximum forward current, which determines achievable range in free-space optical links.

Key Selection Parameters

• Dominant wavelength or CCT — Defines perceived colour for visible LEDs or peak emission for IR types; binning within 5 nm ensures visual consistency.

• Luminous intensity (mcd) or luminous flux (lm) — Brightness output at rated current; high-power devices specify flux in lumens, standard LEDs in millicandelas.

• Forward voltage (V_F) — Typically 1.8–2.2 V for red, 3.0–3.6 V for blue and white; critical for designing current-limiting resistor values and driver topologies.

• Maximum forward current (I_F) — Continuous current rating; exceeding this without adequate thermal management accelerates lumen depreciation.

• Viewing angle (half-angle) — The angle at which intensity drops to 50% of on-axis; narrow angles for focused indicators, wide for flood illumination.

• Package footprint — Through-hole (3 mm, 5 mm) or SMD (0201 to 5050+); match to your PCB assembly process and space constraints.

Representative Parts We Source

Send Us Your LED Requirements

ADD Components supports procurement teams with genuine Osram, Cree LED, Vishay, and Broadcom LEDs — from standard 5 mm through-hole indicators to high-power XLamp arrays for industrial luminaires. Our supply chain covers full production volumes with competitive pricing, manufacturer traceability, and delivery scheduling across Greater China and Asia-Pacific.

Email your bill of materials to Info@addcomponents.hk for prompt quoting. For immediate assistance, call +852 5334 3091 or contact us on WhatsApp at +852 5334 3091.

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