How to Use Level Converter: Examples, Pinouts, and Specs

A level converter, also known as a logic level shifter, is a circuit component designed to translate signals between different voltage levels. This allows devices operating at different logic levels to communicate seamlessly. For example, it enables a 3.3V microcontroller to interface with a 5V sensor or peripheral.

Manufactured by Arduino, the Level Converter (Part ID: UNO) is a versatile and reliable solution for voltage level translation. It is commonly used in projects involving microcontrollers, sensors, and communication modules.

• Interfacing 3.3V microcontrollers (e.g., ESP32, Raspberry Pi) with 5V peripherals.
• Enabling communication between devices with different voltage standards (e.g., I2C, UART, SPI).
• Protecting low-voltage devices from damage caused by higher voltage signals.
• Translating signals for bidirectional communication in mixed-voltage systems.

• Voltage Range (Low Side): 1.8V to 3.3V
• Voltage Range (High Side): 3.3V to 5V
• Maximum Current per Channel: 50mA
• Number of Channels: 4 bidirectional channels
• Operating Temperature Range: -40°C to 85°C
• Dimensions: 15mm x 15mm x 3mm
• Communication Protocols Supported: I2C, UART, SPI, GPIO

The Level Converter has a total of 8 pins, divided into two groups: Low Voltage (LV) side and High Voltage (HV) side.

1. Power Connections:

   • Connect the LV pin to the low-voltage power supply (e.g., 3.3V).
   • Connect the HV pin to the high-voltage power supply (e.g., 5V).
   • Connect the GND pin to the ground of both the low-voltage and high-voltage devices.

2. Signal Connections:

   • Connect the low-voltage device's signal lines to the LV1, LV2, LV3, or LV4 pins.
   • Connect the high-voltage device's signal lines to the corresponding HV1, HV2, HV3, or HV4 pins.

3. Communication Protocols:

   • For I2C communication, connect the SDA and SCL lines to any of the available channels.
   • For UART or SPI, assign the appropriate TX, RX, MISO, MOSI, and CLK lines to the channels.

• Ensure that the LV and HV power supplies are stable and within the specified voltage ranges.
• Do not exceed the maximum current rating of 50mA per channel.
• Use pull-up resistors for I2C communication if required by your devices.
• Verify the pinout of your devices before connecting them to the level converter.
• Avoid leaving unused channels floating; connect them to ground if not in use.

Below is an example of using the Level Converter to interface a 3.3V sensor with an Arduino UNO (5V logic).

• LV → 3.3V power supply
• HV → Arduino UNO 5V pin
• GND → Common ground
• LV1 → Sensor's data pin
• HV1 → Arduino UNO digital pin 2

// Example: Reading data from a 3.3V sensor using a level converter
// Connect the sensor's data pin to LV1 and Arduino pin 2 to HV1

const int sensorPin = 2; // Arduino pin connected to HV1

void setup() {
  Serial.begin(9600); // Initialize serial communication
  pinMode(sensorPin, INPUT); // Set pin as input
}

void loop() {
  int sensorValue = digitalRead(sensorPin); // Read sensor value
  Serial.println(sensorValue); // Print the value to the Serial Monitor
  delay(500); // Wait for 500ms before the next reading
}

1. No Signal Translation:

   • Cause: Incorrect power supply connections.
   • Solution: Verify that the LV and HV pins are connected to the correct voltage levels.

2. Signal Distortion or Noise:

   • Cause: Long wires or improper grounding.
   • Solution: Use shorter wires and ensure a solid ground connection.

3. I2C Communication Fails:

   • Cause: Missing pull-up resistors.
   • Solution: Add pull-up resistors (typically 4.7kΩ) to the SDA and SCL lines.

4. Overheating:

   • Cause: Exceeding the maximum current rating.
   • Solution: Ensure that the current per channel does not exceed 50mA.

Q1: Can I use the Level Converter for unidirectional signals?
Yes, the Level Converter works for both unidirectional and bidirectional signals.

Q2: Can I use this component for analog signals?
No, the Level Converter is designed for digital signals only.

Q3: What happens if I connect the wrong voltage to the LV or HV pins?
Connecting incorrect voltages may damage the component or connected devices. Always double-check your connections.

Q4: Can I use this Level Converter with a 1.8V device?
Yes, the Level Converter supports low-voltage devices down to 1.8V on the LV side.