Introduction
Surface mount LEDs are widely used in all types of lighting, display, automation and electronics products. SMD (surface mount device) LEDs offer compact size, ease of PCB assembly and design flexibility.
There are several common form factors used for SMD LEDs identified by 4 digit or 5 digit alphanumeric codes like 2835, 3528, 5050 etc. These codes precisely define the package dimensions.
This article provides an overview of popular SMD LED package types, their dimensions, characteristics, applications and differences to help designers choose the optimal option.
SMD LED Codes
SMD LEDs have a 4 digit or 5 digit code where:
- First 2 digits denote length in hundredths of an inch
- Middle 2 digits denote width in hundredths of an inch
- Last digit (or 2 digits) denotes height in hundredths of an inch
For example:
- 3528 LED is 3.5mm x 2.8mm size
- 5050 LED is 5.0mm x 5.0mm
- 2835 LED is 2.8mm x 3.5mm
So the codes precisely identify the LED chip dimensions. Let’s look at some common types in more detail:
2835 SMD LEDs
With a size of just 2.8mm x 3.5mm, 2835 LEDs are very compact surface mount devices suitable when a small LED is needed.
Key features:
- Physical size: 2.8mm x 3.5mm
- Very low profile package – ideal for constrained spaces
- Can deliver up to 140+ lumens from 1W chips
- Beam angle: 120-130 degrees
- Simple to mount via surface soldering
- Low thermal resistance for good heat dissipation
- Widely available from multiple suppliers
2835 LEDs are extensively used in display backlighting, signage, accent and task lighting, decorative lighting, automotive interiors and other applications where high density miniature lighting is required. The small and thin form factor allows easy integration even in tight spaces.
Higher light output versions with efficient 1W or 2W chips make 2835 LEDs suitable for a broad range of small form factor luminaires demanding high brightness in a small package.
3528 SMD LEDs
<img src=”https://drive.google.com/uc?export=view&id=1CJwjDruifeGGR6cx1597a9AVynRTYWJW” alt=”3528 LED” style=”width:200px;height:200px;”>
The 3528 LED package has almost identical dimensions as the 2835, with only a change in orientation from 2.8×3.5mm to 3.5×2.8mm. This gives it a slightly longer/narrower footprint.
Key parameters:
- Physical size: 3.5mm x 2.8mm
- Ultra-thin profile – 0.6mm to 0.9mm
- Up to 240 lumens from a 3W chip
- Beam angle: 110 to 130 degrees
- Simple surface mounting via pads
- Low thermal resistance
- Readily available and cost-effective
With their compact dimensions and ability to deliver high lumens from mid-power chips, 3528 LEDs are well suited for small footprint lighting applications where high density and brightness is important – backlighting, small accent lights, signage, decorative lighting, automotive interior lighting etc. The slightly longer package can be beneficial where more space is available in one orientation. 3528 provides a higher lumen alternative to 2835 for small lighting needs.
5050 SMD LEDs
With a 5.0mm x 5.0mm square footprint, 5050 LED packages provide a higher power lighting solution in a small SMD form factor.
Key features:
- Physical size: 5.0mm x 5.0mm
- Low profile body below 2mm
- Can support up to 400 lumens from a 5W chip
- Typical viewing angle between 115° to 130°
- Easy to solder pads for surface mounting
- Thermal pad on base sinks heat to PCB
- Cost effective price point
The compact square shape and moderately high power capacity make the 5050 LED package popular for applications like small downlights, directional and task lighting, architectural lighting, backlighting, automotive interior lighting etc. where the 5mm x 5mm footprint can be easily accommodated. The lower cost also makes 5050 LEDs popular in cost-sensitive but high volume applications.
For small form factor directional lighting needs, 5050 SMD LEDs deliver substantial lumen output while remaining highly integrable due to their tiny surface mount package.
4014 SMD LEDs
With a 4.0mm x 1.4mm rectangular size, the 4014 LED package is even smaller than 2835/3528 LEDs.
Typical characteristics:
- Ultra compact 4.0 x 1.4 mm footprint
- Thickness under 1mm allows integration in tight spaces
- Up to 100 lumens from 1W LED chip
- Beam angle between 120 to 140 degrees
- Simple surface mount assembly
- Requires minimal PCB space
- Lower cost
The tiny 4014 LED package excels in space constrained applications where minimum PCB area is available for lighting. Best suited for low power decorative lighting, backlighting in miniature displays, front panel indicators etc. The thin rectangle design allows packing into narrow elongated spaces.
4014 LEDs deliver lower light output than 2835 or 3528 High brightness is not possible due to the tiny 4×1.4mm size. But the highly miniaturized package enables lighting integration in extremely compact products.
5630 SMD LEDs
Similar to 5050 LEDs, the 5630 LED package has a wider 5.6mm x 3.0mm rectangular footprint:
Key attributes:
- Rectangular size of 5.6mm x 3.0mm
- Component height under 1.9mm
- Capable of 550+ lumens from a 5W chip
- Beam angle between 110° to 130°
- Thermal pad assists heat dissipation
- Easy surface mount soldering
- Utilizes mid-power to high-power LED chips
- Lower cost than 5050 package
With the capability to deliver very high lumen density from the larger mid-power to high-power chips, 5630 LED packages are ideal for small high brightness lighting applications like downlights, spotlights and track lighting where the wider 5.6mm width can be accommodated. The smaller 3mm height assists integration in constrained height products.
7070 SMD LEDs
With a compact 7.0mm x 7.0mm square shape, 7070 LED package offers enhanced brightness vs 5050 LEDs:
Typical features:
- 7.0mm x 7.0mm size
- Just 1mm profile
- Up to 1000 lumens from a 10W LED chip
- Beam angle between 115° to 140°
- Simple surface soldering
- Thermal pad for heat conduction
- Utilizes higher power LED chips
- Higher lumens than 5050 package
The 7070 LED leverages advanced mid-power to high-power LED chips in the 7x7mm footprint to deliver very high lumen density with easy integration – making it ideal for applications like compact downlights, reading lamps, accent lighting, architectural lighting etc. where high brightness in small footprint is needed.
The 1000+ lumen output rivals that of much larger COB LEDs while retaining the design flexibility of the tiny SMD package.
5730 vs 8050 vs 9050 SMD LEDs
There are several other less common similar large SMD LED package types with minor size variations:
5730 – Rectangular 5.7mm x 3.0mm
8050 – Square 8.0mm x 8.0mm
9050 – 9.0mm x 9.0mm square
These all have similar characteristics as the 5630 and 7070 SMD LEDs – able to deliver very high lumens from >10W LED chips due to the larger surface area.
So they are also well suited for high density high power lighting applications where their particular size can be most easily integrated into the product design.
Comparing Key SMD LED Types
Comparison of popular SMD LED packages:
| Package | Size (mm) | Chip Power | Lumen Output | Key Applications |
|---|---|---|---|---|
| 2835 | 2.8 x 3.5 | 1W | 100-140 lm | Display backlights, Miniature lights |
| 3528 | 3.5 x 2.8 | 1-3W | 100-240 lm | Signage, Mini lights |
| 5050 | 5.0 x 5.0 | 3-5W | 240-400 lm | Accent lights, Task lights |
| 5630 | 5.6 x 3.0 | 5-10W | 550+ lm | Directional lighting |
| 4014 | 4.0 x 1.4 | 0.2-1W | 60-100 lm | Decorative, indicators |
| 7070 | 7.0 x 7.0 | 10W | 1000+ lm | High power downlights |
This covers the most popular SMD LED package types commonly available. There are also less common larger packages like 1210 (12mm x 10mm) which can drive 1.5A or higher currents.
COB vs SMD LEDs
COB or chip-on-board LEDs combine multiple bare LED chips directly mounted on a PCB substrate within a LED package. The main differences between COB LEDs and SMD LEDs are:
SMD LEDs
- Contains a single LED chip in compact form factor
- Widely available in standard package sizes
- Allows design flexibility
- Lower cost per lumen
COB LEDs
- Combines multiple LED chips for very high lumens
- Custom rectangular size and lumen rating
- Simpler optics design
- Higher luminous efficacy
For most common lighting applications, SMD LEDs deliver the best balance of flexibility, density and cost effectiveness. COB LEDs are more suitable where very high lumen density is absolutely necessary.
Conclusion
Understanding the standard SMD LED package types, dimensions, characteristics and typical applications allows designers to select the optimal option. SMD LEDs deliver excellent design flexibility, ease of integration and thermal performance in lighting products.
With high brightness mid-power to high-power SMD LED packages now available from reputable suppliers at continually reducing price points, lighting manufacturers can leverage SMD LED technology build compact, efficient, cost-effective and reliable luminaires.
FAQs
How is the viewing angle of SMD LEDs controlled?
The LED chip encapsulant lens design primarily determines the viewing angle. LEDs with different angle options allow designers to choose the beam width needed.
Why are SMD LEDs preferred over through-hole LEDs?
Easier automated assembly, improved heat sinking, lower profile and aesthetic appearance makes SMD LED packages overwhelmingly popular now.
What is the typical lifetime of mid-power LED SMDs?
When used within specifications, mid-power SMD LED chips achieve 50,000 hours of lifetime with 70% lumen retention making them suitable for most applications.
How does lower thermal resistance help SMD LED performance?
Lower thermal resistance allows the LED package to dissipate heat better. This reduces the chip junction temperature and improves luminosity, efficacy and lifespan.
What is the difference between top view and side view SMD LEDs?
Side view SMD LEDs emit light laterally and are used when lighting edge-mounted acrylics and light guides. Top view SMDs emit upward and are used in most standard lighting.
