Definition
SMD (Surface-Mount Device) LEDs are the most common LED package type in commercial lighting — compact rectangular chips soldered directly onto printed circuit boards (PCBs) using automated pick-and-place assembly. Each SMD package contains one or more LED dies, a phosphor coating for white light conversion (in white LEDs), and a reflective cavity that shapes the light emission pattern (typically 120° wide angle). Standard SMD sizes are designated by package dimensions: 2835 (2.8×3.5mm — the workhorse for panels and strips), 3030 (3.0×3.0mm — high-power for outdoor/flood), 5050 (5.0×5.0mm — multi-die for high output), and 5630 (5.6×3.0mm — high efficacy). SMD LEDs dominate approximately 85% of general lighting applications due to their mature manufacturing ecosystem, low cost, and proven reliability.
Key Data
| Parameter | Value / Explanation |
|---|---|
| SMD 2835 | 2.8×3.5mm, 0.2-0.5W per chip, 20-70 lm/chip, 120-200 lm/W. Dominant in LED panels, tubes, strips. |
| SMD 3030 | 3.0×3.0mm, 0.5-1W, 50-150 lm/chip. High-power outdoor, flood, street light applications. |
| SMD 5050 | 5.0×5.0mm, multi-die (3-4 dies), 0.5-1.5W, 60-200 lm/chip. RGB/RGBW color mixing possible. |
| SMD 5630/5730 | 5.6×3.0mm, 0.5W, 50-80 lm/chip, high efficacy. Premium panels and downlights. |
| Typical beam angle | 120° (Lambertian) without secondary optics. Secondary lenses narrow to 15-90° as needed. |
Application Guide
Office LED panel
SMD 2835 or 5630, 120° beam, 100-130 lm/W system
Cost-effective, uniform light distribution, mature supply chain
LED strip (cove/decorative)
SMD 2835 (120-240 LEDs/m) or 5050 (RGB), 12V/24V CV driver
High density for dot-free illumination; 5050 for color-changing applications
Floodlight / outdoor
SMD 3030 or 5050, secondary optics 30-90°, IP66 housing
Higher power per chip enables longer throw distances; robust thermal path
Conclusion & Procurement Recommendation
For B2B procurement, SMD LED selection should focus on: (1) Brand of the LED chip — Cree, Lumileds, Nichia, Seoul Semiconductor, Osram, and Samsung command 20-50% price premiums over generic chips but deliver verified LM-80 data and consistent binning, (2) Binning tolerance — specify ≤3 MacAdam ellipses for color consistency across fixtures, (3) LM-80 test reports for the specific SMD model at the actual drive current and temperature used in the luminaire. Key pitfall: many luminaires use 'Cree-style' or 'Lumileds-compatible' SMDs that are actually generic clones — request the manufacturer's certificate of authenticity for branded LEDs if specified in the BOM.