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Basic Knowledge of SMD Chip for Newcomers to LED Lighting

0 2018-10-25 09:57:46

SMD stands for Surface Mounted Device and is currently the most welcomed LED package type. SMD LED lights are produced by using surface mounted technology (SMT) to mount SMD chips on printed circuit boards (PCB).

SMD chips are designed to a variety of flat-square shapes and sizes, which have many types. The most common types of SMD chips are: 3528, 5050, 2835, 3014, 4014, 3020, 5730, 3030 and 3535. The number indicate the chip size, for example, 3528 is for the chip with size 3.5 x 2.8mm. (some of SMD chips can be made with very small size and can be used as indicator lights of cell phones and laptop computers. The little light of cell phone which stays on after the screen turns off is powered by a small SMD chip.) 

SMD chip is a very important development for the LED industry because of the ability to put 3 diodes on the same chip. When a chip includes a red, green and blue diode, then it has RGB ability and can create any color you want by adjusting the level of output from each individual diode on the chip. If the chip with 3 same diodes, it will increase the output lumen. For example, 3528 has only one diode, while 5050 has 3 diodes on its chip, thus 5050 has the RGB ability on the single chip and 3 times output lumen of 3528. (4 in 1 designed 5050 has RGB+W ability and 4 times output lumen of 3528.) 

Unlike only two contacts designed for DIP chip, SMD chips may have 2, 4 or 6 contacts (called pins), which depends on the quantity of diodes on the SMD chips. For SMD chip, there is an individual circuit for each diodes and each individual circuit is designed with 2 pins. For example, 5050 has 3 diodes on its chip, thus it has 6 pins. (5050 RGB+W type gets 4 diodes with total 8 pins.)

The power consumption (W) and output lumen (LM) comparison of each SMD chip is listed as the following chart:

SMD Chip Power Consumption (W/PC) & Output Lumen (LM/PC)

3528   0.06W, 6 - 9LM, always designed for low power purpose

5050  0.18W, 18 - 27LM, mainly designed for low power purpose

But currently middle power (0.5W) and high power (1-3W) have been developed, especially for RGB and RGB+W type

2835   0.1W, 10 - 15LM;

0.2W, 20 - 30LM, for low power purpose

0.5W, 50 - 65LM, for middle power

1W, 100 - 130LM, for high power

3014   0.1W, 9 - 13LM;

0.2W, 18-24LM, always for low power purpose with high bright feature

4014   0.2W, 24 - 26LM, always for low power purpose

3020   0.06W, 7 - 8LM;

0.1W, 9 - 11LM;

0.2W, 18 - 24LM, for low power purpose

0.5W, 50 - 60LM, for middle power purpose always with EMC reflector

5730   0.5W, 45 - 60LM, main for middle power purpose

1W, 90 - 120LM, for high power

3030   1W, 100 - 130LM, always for high power purpose 

3535   1 - 3W, - LM, always for high power purpose with EMC or SMC reflector

You can easily calculate the power and output lumen of SMD LED lights through above chart. This chart for the various types of SMD chips and their correct lumen,but LED technology is developing, the data may be changed in near future.

From the chart, according to the power consumption (W/PC), SMD chips can be divided into 3 classes which are low power (<0.5W/PC), middle power (0.5-1W) and high power (>1W). For the SMD chip, the higher the power is, the more heat it will dissipate and the higher the temperature it will be when working. Then the higher temperature the reflector of SMD chip can resist, the longer life-span SMD chip will get. Thus the quality of reflectors greatly affects the life-span of SMD chip. Therefore different reflectors are needed for different power levels. The main reflector materials for SMD chips are PPA (Polyphthalamide), PCT (Polycyclohexylene-dimethylene Terephthalates), EMC (Epoxy Molding Compound) & SMC (Silicone Molding Compound).

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