5V – 3.3V Logic Level Converter IC for Arduino and Raspberry Pi

Hey Guys welcome back to RootSaid. In this Post, I will show you how you can make your own 5V to 3.3V logic converter for connecting 5V sensors to new Arduino Boards and Raspberry Pi. 

Why do we need a Logic Level Converter IC?

Most of you love playing with Arduino and Raspberry Pi during free time right? Of Course that’s what hobbyists do! 

Along with Arduino, we will definitely use various sensors such as IR sensor, PIR sensor and Ultrasonic sensor. But the problem is most of today’s boards are not 5 V tolerant and almost all of the boards works under 3.3V.

Does that mean we cant use our old sensors anymore?

Not exactly. Almost all of the microcontrollers works under 3.3V logic these days. Most of the devices that works under 3.3V do not like being provided with 5V and will get burned in seconds. So what can we do about it? Luckily, there is a way, there are logic level shifters that will convert 5V to 3.3V. One such IC is 74LVC245.

74LVC245 Logic Level Converter IC

This chip solves the problem of connecting and sending data from 5 V logic level devices to a 3.3 V logic microcontrollers such as Raspberry Pi and Arduino. This chip stands in between Arduino and the Sensor and converts the 5V signals from the sensor to 3.3V which can be directly fed to Arduino.

74LVC245 can be used with digital signals and works great with SPI, Serial, Parallel bus, and other logic interfaces.

Making the PCB

Surface Mount Technology is the technique of assembling PCBs by mounting the components on the surface of the board. Unlike the traditional method of placing the components through holes and soldering them on the other side, in SMT, the components are placed over the board and the leads are soldered on the same side. 

JLCPCB is one of the best Online PCB manufacturing companies from where you can order PCBs online without any hassle. The company works 24 hours a day, 7 days a week nonstop. With their high tech machinery and automated work stream, they can manufacture huge quantities of high-class Assembled PCBs within hours.

Designing the Circuit 74LVC245 Logic Level Converter IC

You can easily go to EasyEDA website and start a new project. Once you have opened a new canvas, start adding components. For now, JLCPCB have 689 Basic components and 30k+ Extended components at your disposal. See the complete list of components here.

5v to 3.3v logic level converter Circuit diagram
5V to 3.3V logic level converter Circuit diagram

Make sure you add the components from this list while drawing the schematics in EasyEDA. You can even search for the components and check its availability.

Search for the components from the library and place it in the canvas. Use “Wire” tool to connect the components together. 

Working with this IC is pretty simple. You can setup the circuit in a matter of minutes.

  • Simply connect VCC to your logic level you want to convert to. If you are converting 5V to 3.3V, connect 3.3V to VCC. 
  • Ground connects to Ground. 
  • OE (output enable) to ground to enable the chip
  • DIR to VCC (3.3V). 

PCB Layout

Once you have finished drawing the circuit, save the circuit by clicking save and create PCB layout. I will provide links to all the files including the Gerber, Pick n Place and Bill of Material in the description.

You can now download the Gerber file and use it to manufacture your PCB from JLCPCB. Gerber File contains information about your PCB such as PCB layout information, Layer information, spacing information, tracks to name a few. Now let us order it. 

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