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Article Updated: 24 Aug 2021

Which SMD LED chips are the brightest and most efficient? 5050, 5630, 5730, 2835 or something else?

SMD LED Chips Characteristics: Size, Power, Efficacy

SMD LED chips have greatly evolved over the past couple of decades. With the cost per lumen exponentially decreasing now they come in all different shapes and sizes you can possibly imagine.

SMD LED CHIPS

Ideal Light Source: 100% Efficacy

Luminous efficacy of the visible light spectrum radiation (LER) is expressed in Lumens per Watt (lm/W) unit. Maximum theoretical efficiency of ideal light source is equal to 683 lm/W at 555 nm monochromatic green color wavelength.

Why 555 nanometers you may ask? Because, standardized V(λ) curve that describes average human eye sensitivity to visible light peaks exactly at that number! We have to thank our surroundings in nature for that, obviously! In another words, an ideal LED light source would emit “pure green” and convert 100% of consumed electrical energy into light, achieving above maximum theoretical efficiency limit.

But, what about other colors? What about red, blue, yellow, orange and white? Well, whenever we shift, spread or stretch spectrum of emitted light to include other colors in the output, we reduce maximum theoretical efficiency. Why? Because our eyes are not that sensitive to other colors, particularly to the extreme blue (< 450 nm) and extreme red (> 700 nm) ends of the scale, and we are completely blind to ultra-violet and infra-red (IR) spectrum and beyond.

White light LEDs have a maximum theoretical efficacy around ~ 350 lm/W, which means that we are not there yet, but we are getting really close! Cree (who sold its LED business to SMART Global Holdings, Inc. in 2020) was the first company to breach 300 lm/W efficacy barrier, according to company’s official press release (2014). So, why aren’t we seeing them in our tables listed below and online stores ready for purchase? Because those are R&D laboratory specimens test results, they are either extremely rare and expensive to produce (requiring high precision and expensive and tight material and mechanical tolerances for mass production at our current technological levels), and availability is thus very limited. They are both exclusive and expensive for the time being.

How are White LEDs made?

There are 3 methods currently available, each having certain advantage over the other:

1. Using R-G-B LEDs (without phosphor dyes acting as wavelength converters). We can make an illusion of a white light by properly mixing values of RED, GREEN, and BLUE components, respectively. Note that all 3 LEDs have different electrical characteristics that needs to be addressed (namely, operating voltage and current requirements), thus making controller logic more complex and expensive. This method may be very easy and efficient, but tends to produce gaps in the spectrum, resulting in lower CRI (80-85). In addition, because of different materials (composition), wear and tear levels (aging) change differently for each color over time, affecting stability and quality of light.

   Where can we see an example of RGB LEDs and white light which they produce? Well, if you happen to have an OLED/AMOLED display on your mobile phone, PC or laptop monitor, you may already be looking at it, because those screen technologies use an active RGB (or interleaved RGBW) LED matrix to create an illusion of many colors, including white! If you have a macro mode on your digital or spare phone camera (combined with an optical or digital zoom — it will likely help), you can take a magnified picture of individual LED sub-pixels and see it for yourself! Please note that older traditional TFT LCD screen technology does not actually use LEDs in front, but a colorized RGB glass filter bars passing or blocking backlit white light unit (BLU), which may trick you into thinking that they are LEDs, but they are not!

2. Using Blue LED with phosphor-based dyes on top (under the lens cover). That yellow or orange paint you see on top of many white SMD LEDs or COB LED panels is actually called a wavelength converter, special dye layer exploiting quantum principle of wavelength / frequency conversion. Blue LEDs are typically running at 450-460 nm wavelength. Different dyes will produce different spectrum shift and resulting “white color” (warm, natural, cold). Some specialized dyes can produce very high CRI values (95-98). Phosphor dyes are characterized by their own internal quantum efficiency, which affects overall LED efficiency, as well.
3. Using UV LED with phosphor-based dyes as wavelength converters on top (under the lens cover). UV LEDs are typically running at 365-395 nm wavelength.

SMD LED Chips: Key Properties

• Radiant Flux (Lumens) output per single chip. It depends on power rating and efficacy, size, geometry, grade / bin, electrical characteristics and operating conditions.
• Efficacy expressed in Lumens per Watts (lm/W) ratio is related to Radiant Flux and how strong LED shines with respect to consumed electrical power. Despite popular belief, maximum power efficency of a LED chip is achieved at much lower power level than its maximum power rating! Lumens per Watts vs Forward Current (Amps) chart has approximately a shape of an exponential decay curve. For this very reason many energy efficient designs incorporate at least 30-100 % more LED chips than absolute minimum, to avoid lower efficiency, keep chips cooler, and drive them at “sweet spot”. In a typical design drive current rarely exceeds LED’s nominal value, and to keep thermal management under control they are often under-driven by 30-50 %, well below their nominal and absolute maximum ratings. There are, of course, other cases where power efficiency is not the main goal — total light output is, and in those cases LEDs are driven to the max with large heatsinks attached behind.
• Beam width of emitted light rays (2D or 3D angle) — defined by boundary where light intensity falls off to 50%. Incandescent light bulbs approximately shine in 360 degrees, while common LEDs are usually considered as focused point sources with beam angle from 15 to 120 degrees. It is typically controlled by chip geometry and shape of focusing lens placed on top, which can be added later after chip manufacturing process. Lens introduces 5-10 % drop in lumens output (efficiency loss), depending on its optical transmittance value, which is usually around 90-95 %.
• Spectral Response is another important characteristics. Polychromatic LEDs are derivatives of blue LED with various ratios of blue, yellow, green and red wavelengths, forming a wide range of color temperatures from amber / warm, natural / neutral to cold (bluish) white. The quality of “white” is determined by phosphor coating on top of the LED chip. Monochromatic LEDs are specialized in relatively narrow range of the spectrum from ultraviolet (UV), visible (RGB and other colors) to infrared (IR) light.

SMD LED Chips: Typical Characteristics

Data is generalized and greatly simplified to get an idea, but in reality things depend on production batch, post-production classification (grades / bins) and other characteristics specific to each manufacturer.

• Typical 0.2 Watt white SMD LED (e.g. 2835, 5050) works at ~ 3.0 Volts (2.8 ~ 3.6), runs at 60 mA nominal drive current and produces 20-35 lumens per single chip. When run at lower currents (20-40 mA), output flux is reduced to 6-15 lumens per single chip.
• Typical 0.5 Watt white SMD LED (e.g. 2835, 5630, 5730) works at ~ 3.2 Volts (2.8 ~ 3.6), runs at 100-150 mA nominal drive current, and produces 30-90 (50-60 typical) lumens per single chip. When run at lower currents (45-60 mA), output flux is reduced to 10-30 lumens per single chip.

Typical values for a 5050 LED chip are:

• 200 mW (0.2 Watts) Maximum Power Rating
• 120° degrees beam width
• 8~14 lumens per single LED chip, but it may be as high as 24
• 5050 are typically brighter than 3528 chips, but less powerful than 5630 and 5730
• 5050 LED flex strip (tape) of equal length, voltage rating and number of chips will produce more light and it will also require much larger driving current (~ 4 times) than equivalent 3528 and 2835 cheaper variants

SMD LED Chips: General Introduction

Contemporary discrete SMD LED chips are: SMD5050, SMD5054, SMD5630, SMD5730, SMD2835, SMD3014, SMD3528 and so on.

First 2 digits denote width; second 2 digits denote length (all units are in 1/10th of a millimeter or mm, for short). Unfortunately, size designation alone does not tell us absolutely anything about their electrical and light emitting characteristics!

According to various datasheets, most powerful and efficient ones are 3535 types (up to 1500 mA / 5 Watts / 180 Lumens), 2016 (60 mA / 0.2 W / up to 200 Lumens per single chip), and 2835 types (150-300 mA / 0.5-1.0 Watt / up to 180 Lumens per single chip), but beware, much more common are 60 mA / 0.2 W cheaper variants found in budget LED strips and lamps that are worse (weaker or less bright) than 5050! They are closely followed by 3030 types (150 mA / 1 Watt / up to 165 Lumens per single chip). In the midrange class are 5054, 5630 and 5730 types (up to 150-300 mA / 0.5-1.0 Watts / 60-150 Lumens) — more powerful than 5050/5060 types — again beware of cheap low power 0.10 ~ 0.15 W and 7 ~ 12 Lumens types commonly found in affordable LED strips and lamps. Cree produces special high-efficacy 5630 J series which can reach 209 lm/W! Finally, 5050 / 5060 types are at the lower power handling end (up to 60 mA / 0.2 Watts / 24-32 Lumens per single chip), but they are very efficient, cheap and affordable, offer excellent strong light output for typical applications, which makes them a very good budget choice! There are other sizes and types as well, but these are the most popular ones used today.

As a general rule, the more powerful chip is (e.g. it handles higher input voltage and current), the more light it produces (in total), but the less efficient it is. In another words, driving high-power chips at 40-50 % of their nominal power rating will usually produce peak efficacy [lm/W] or LPW rating, while driving them further towards their nominal (maximum continuous) rated specs will lower that ratio. Most efficient chips are usually lower 0.2 W types, because they operate at lower temperature, they are easier to produce and get “perfect bins” during production.

Once again, keep in mind that data varies by manufacturer, class (price), application, and also changes with each new generation of LEDs; consequence of a rapidly developing industry. Cheaper (low power) ones usually find their usage in products such as USB LED lamps or LED strips. More expensive ones are reserved for a higher class of products, with their respective price. But, higher power and light output (lumens) translates into more battery power required to drive them (and, consequently, generated heat), which is something of a luxury and design constraint in miniature portable devices and applications.

We need to mention cheap LED “clones” designed to “look” and “feel” like the real ones. They are common in budget / low-end LED strips, lamps, lightbulbs etc. What makes them so inferior and weak? Essentially, they use thinner and smaller silicone substrates, wires, less copper (in strips / tapes), smaller heat-sinks, bad power regulators and so on. If you measure their weight, you will find that they are often 2 to 3 times lighter than their “original” counterparts. All that makes them prone to greater heating, ultimately limiting their absolute maximum power ratings and lifespan.

LED chips also come in different power and operating voltage ratings, too. Although, this is mainly achieved by additional controller and resistor network circuits, or stacking chips in series, resulting in operation at higher rated voltage than nominal LED silicon excitation values.

Common modern SMD LED of white or blue color operates under 2.7 ~ 3.6 Volts (matches modern Lithium-based or 2 (or 3) x AA/AAA standard batteries), but there are also other variants: for 5 Volts (USB bus powered), 12-24 Volts (car/truck accumulator powered and in common household lighting applications), and all the way up to mains 110-220 V AC grid power supply (home-office-industry use). Voltage boosters or step-down converters are used to either boost lower voltage (1-3 volts) into higher one (5-12 Volts), or rectify and scale down mains power supply.

Some LEDs can be driven with higher voltage (e.g. 3.7 ~ 4.5 V for white LEDs), but that greatly shortens their lifespan, and even prematurely burns them! There are also special high-voltage types (6-18 V or more) with high efficacy.

LED chips are non-linear electronic components (V-I curve), very much like their ordinary non-light-emitting relatives, which means that their light output performance greatly varies with the variation of input voltage. This makes very little concern in applications such as portable battery-powered LED lamps, but in professional and home lighting applications, it is of a great importance. In constant voltage (CV) mode, current limiting resistors are used, most notably with LED strips, USB LED lamps, “corn” bulbs, ceiling lamps and so on, however, resistors lower the overall efficiency because excessive power from the power supply or battery is wasted into heat. This is why constant-current driver circuits (CC) should be used, since LED brightness can be controlled more linearly by the amount of electrical current passing through the chip in active manner without excessive power waste.

SMD LED Chips Characteristics: Size / Power / Efficiency / Specs Table

Initial table data source (edited, updated, corrected for errors, data is provided as-is)

[1] Flux and Luminous Efficacy is stated for polychromatic visible light spectrum (e.g. warm, natural or cold white). It is considerably lower in monochromatic types, except for green laser at 555 nm, of course. Also, see [2] and [4] below.

Flux and Lumen Efficacy values are rounded.

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[2] Heatsink is recommended for prolonged or continuous operation at high or near maximum rated power. In low-power types (0.2 ~ 0.5 W) heatsink can be omitted at lower power levels (< 0.1 W), but chip lifespan will be greatly reduced when run at higher power output without proper cooling from our experience (this is particularly true for cheap LEDs despite datasheets claiming otherwise). Higher operating junction temperatures negatively impact luminous output and efficacy (as much as 20-30% reduction in light output intensity is observed), while sub-zero temperatures (in Celsius) can increase light intensity by the same amount! In addition, running LEDs at high brightness and temperatures increases material wear and dimming phenomena over time (you probably heard of screen burn-in on mobile phone and TV displays -- which also affects related entirely different TFT LCD technology, as well!). For this reason, we suggest a mandatory heatsink surface when running at high or maximum rated power levels. COBs and portable lamps use aluminum substrate as part of integrated heat sink PCB design.

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[3] With Flux and Beam Angle given it is easy to calculate equivalent Candela (Cd) output using standard formula:

Iv [cd] = Φv [lm] / (2π(1 – cos(θ/2)))

where Iv is luminous (light) intensity in candela, Φv is luminous flux in lumens, and θ beam angle in degrees.

Further, if we replace θ = 120° degrees (typical) in above equation and simplify it, Lumen-Candela equation becomes:

Iv [cd] = Φv [lm] / π
Iv [cd] ≈ Φv [lm] / 3.14
Iv [cd] ≈ 0.32 * Φv [lm]

In another words, luminous intensity expressed in candela is roughly equal to 1/3 for a given luminous flux with LED beam angle equal to 120° degrees.

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[4] High CRI (color rendering index) [Ra] chips typically have lower efficacy (lm/W) and brightness. Specialized chips may have CRI Ra value up to 98 according to some manufactures. High CRI lighting is suitable for professional photography and videography (think Hollywood), but also for well designed homes, public and office spaces, albeit at reduced efficacy.

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[5] Chip package only. Does not include soldering pins on chip’s sides.

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[6] High Power LEDs commonly work at 3.0-3.6 Volts and require 0.35 ~ 1.0 Amperes per chip. High voltage types typically work at 6, 9, 12, 18 or 36 Volts and require 0.15 ~ 0.30 Amperes per chip. This is either achieved by stacking multiple chips in a single package (like a LED module) or using special production process. Examples are Cree SMD 2835 J series with 1 Watt rated power and efficacy reaching almost 180 lm/W (P class), and Cree SMD 5050 6 Volts J series with 5 Watt rated power and efficacy reaching 175-201 lm/W (K class).

COB LED Light Modules

COB (chip-on-board) LED Light is the latest and greatest trend among LED lighting world, breaking away from traditional discrete packaging and densely packing as much integrated chips as possible on an arbitrary shaped area made of insulation layer and aluminum substrate (heatsink): circle, square, rectangle, moon-shape, star-shape… Phosphorus layer is spread over entire COB shape, contributing to their unique appearance. Note that basic aluminum substrate provides bare-bone short term COB cooling, and much larger heatsink must be added separately if run at maximum power.

COB LED Lights – Various Products (not to scale)

Specifications of lumens output (flux), efficacy and power requirements vary between manufacturers, batches, and modules, but in general produce a very bright light (e.g. > 100 Lumens/Watt), require 1 ~ 100 W of power, and 3 ~ 12 V DC or mains power supply (110 V ~ 240 V AC).