SMD Soldering (SOIC Package)


Introduction: SMD Soldering (SOIC Package)

About: A passionate Electronics and telecommunication engineer. Interested in RF, analog, Embedded Systems and IoT.

As you know ICs or Integrated circuits are available in various sizes and packages. Some examples are PDIP or DIP(Plastic Dual in line Package), SOIC(Small outline IC), TQFP(Thin Quad Flat Package), BGA(Ball Grid Array), etc. Basically any package other than DIP is called as SMD(Surface Mount Device).

The PDIP/DIP package is the most common one and can be easily soldered. Many of the widely used ICs for hobby projects are manufactured in DIP. But when it comes to industrial applications, IC's size and power consumption matters. So usually industrial variants of the same ICs are manufactured in smaller packages. If you want to use them in your projects it is very difficult to solder them.

So here's a small instructable on how to do SMD soldering.

I always wanted to try SMD soldering. When I was new to electronics I used to think only professionals with hot air guns or computerized machines can be used to solder SMD chips. I was not able to make many projects due to this limitation.

During my summer vacations I was getting bored. I had a couple of SMD chips lying around. I started with soldering them. I was successful in soldering them.

Did you also face problems while making electronic projects due to SMD chips?

Don't worry, I'm here to teach you how to SMD Soldering. Its really easy. Here I'm going to solder a SOIC.

Step 1: Things You'll Need

1)25W soldering iron (25 W is ideal, the heat may damage the SMD IC.)

2)Needle type bit for Soldering Iron


4)Double sided tape (To hold the SMD IC in place)

5)Thin Multi-strand wire

6)Scissors or wire cutter

Step 2: Preparing the Things on Your Workbench

Start with the thin multi strand wire.(See the pic)
Take a long piece of the wire(approx. 10 cm.).Strip the outer insulating material of about 1.5 cm of wire.
So now the inside metal wire is visible. Twist the strands together.(See the pictures for clear understanding)

Heat the soldering iron. Apply the tip of soldering iron to the bare twisted wire and solder it.The solder will flow on the twisted wire making it solid.

Now take the SMD IC. Place it on a flat surface and stick a double sided tape so that IC is fixed and doesn't move while soldering.(See the pic)

Step 3: Start Soldering

Now that the IC is fixed on the table. Take the wire you prepared. Now keep the soldered end of the wire on one of the pin of the SMD IC and touch it gently with the hot soldering iron.

The solder present on the wire is enough to solder the wire to the pin of the SMD IC. If you feel that solder is less or it is not getting soldered properly you can apply a small amount of solder.

Now cut the remaining part of wire which is insulated. You will get one pin of IC soldered with the wire.

Now repeat the step of stripping 1.5 cm of wire,twisting and soldering.

In this way you can solder your self made wire pins to the SMD IC. And the IC is ready to be used in your project.

See the pic of the final soldered IC.

Step 4: Precautions While Soldering SMD ICs

1.Use a smaller power rating soldering iron. I'm using a 25 watts iron.

2.Don't apply heat to the SMD IC for more than 2-3 seconds. If you are not able to solder the pin within that time, try again after waiting for some time. Let the IC become cool.

3.Take care while soldering don't short the pins. Once all the pins are soldered check for any short circuit using a continuity tester or a Digital Multimeter (DMM).

4.Use of a magnifying glass is highly recommended.

5.Take special care while handling SMD chips. They are sensitive to electrostatic discharge. Take care that no CRT monitor is placed nearby.



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    16 Discussions


    Reply 2 years ago


    Nice job! However I was expecting more of a instructable on how to solder the TQFP IC as shown in your first photo. I think that those are the real challenge, being you have to understand how to use solder wick and that.

    10 replies


    TQFP can also be soldered in the same way. Only thing is you need a more thin wire, lower wattage soldering iron and ESD protection.As you can see the TQFP is kept in a special package. It is ESD sensitive.As of now I don't have the ESD protection gloves and other stuff.

    I will post the instructable soon.

    You can use an anti-static wrist strap that has the other end grounded. Simple to use, problem solved. No gloves needed.

    I don't think so. As you can see the photo below, the most SMD component is made to directly soldered onto the premade PCB board. It's ok too if you use 8 pin PDIP IC as normal through hole IC but it is very bad-bad idea to solder it on an though hole PCB

    Capture 2.PNG

    Premade PCBs for soldering SMD PCBs are available. You also get adaptors for SMD ICs. But they are costly. At least in my country (India).
    Lets say if 555 is available for Rs.20(SMD) then the cost of adapter or PCB itself is around Rs.50

    Oh yes. I mean that tiny QFT IC can't be mounted on any PCB board with this technic. It's insane and not realistic. And why would you need to buy a SMD chip with an adapter and use both of them on a though hole PCB when you can buy a PDIP IC? o_O

    Not all the chips are available in PDIP.
    I have many of the chips in SOIC package. Some industrial ICs, I have a digital potentiometer with EEPROM from Maxim Integrated which is available only in SOIC or TQFP. So, if I want to use that IC, I don't have any other option than buying a PCB or adapter.
    That's what I have written in the instructable also.

    Yes all I mean are:

    1. Through hole IC = SMD IC + adapter => then choose through hole IC

    2. In case you have to choose SMD IC, wiring it is bad idea if it has too much legs

    Premade PCBs for soldering SMD ICs*

    And if you want to make yourself an ESD wrist strap, check out my instructable ;)