4-Channel Bi-Directional Logic Level Converter – 3.3V to 5V (BOB-12009)

Connect 3.3V ESP32 Logic to 5V Devices

This 4-channel bi-directional logic level converter allows microcontrollers and digital devices operating at different logic voltages to communicate safely. It is commonly used to connect 3.3V ESP32, Raspberry Pi and other 3.3V systems to 5V sensors, modules and microcontrollers.

Important: This module does not generate 5V from 3.3V. It is a logic signal converter, not a voltage boost converter. The board requires both voltage rails to be supplied by your project. For a typical ESP32-to-5V application, connect 3.3V to the LV pin and 5V to the HV pin.

Want a version that lets you connect a 5V module to your ESP32 without an external power supply? Look at this option.

Power Requirements

The BOB-12009 requires a low-voltage reference and a high-voltage reference in order to translate signals between the two voltage levels.

• LV: Connect to the low-voltage supply, typically 3.3V when used with an ESP32
• HV: Connect to the high-voltage supply, typically 5V
• GND: Both systems must share a common ground

The module uses these voltage rails as references for the logic conversion. It does not contain a boost converter or voltage regulator that creates the high-voltage supply.

If your project only provides 3.3V and you need both a 5V power supply and 5V logic, you will need a separate 3.3V-to-5V boost converter or a logic level converter with an integrated boost converter.

Using This Level Converter with an ESP32

ESP32 microcontrollers use 3.3V logic, while many sensors, displays and other electronic modules are designed for 5V logic. This converter provides a way to interface the two systems when both 3.3V and 5V power rails are available.

A typical ESP32 connection would be:

• ESP32 3.3V: Connect to LV
• 5V supply: Connect to HV
• ESP32 ground: Connect to GND and share ground with the 5V device
• ESP32 signal: Connect to an LV channel
• 5V device signal: Connect to the matching HV channel

For example, a signal connected to LV1 on the 3.3V side corresponds to HV1 on the 5V side.

• LV must be tied to the low-voltage rail, such as 3.3 V
• HV must be tied to the high-voltage rail, such as 5 V
• grounds must be common

What Is a Logic Level Converter?

A logic level converter, also called a logic level shifter or voltage level translator, changes the voltage level of digital signals so devices using different logic voltages can communicate.

This is different from converting power-supply voltage. A logic level converter changes signal voltage. A boost converter changes power-supply voltage.

4 Bi-Directional Logic Channels

The BOB-12009 provides four separate bi-directional signal channels. Signals can pass from the low-voltage side to the high-voltage side or from the high-voltage side to the low-voltage side without a separate direction-control input.

This makes the module particularly useful for bi-directional communication buses such as I2C.

Common Applications

• ESP32 3.3V logic to 5V modules
• Raspberry Pi 3.3V logic to 5V electronics
• Arduino 5V logic to 3.3V sensors
• I2C level shifting
• UART serial communication
• Digital GPIO signals
• Sensors and peripheral modules
• Mixed-voltage microcontroller projects

Best Suited for I2C and Similar Signals

This MOSFET-based bi-directional level converter is particularly well suited to I2C and other open-drain signals. It can also be used with many UART and general-purpose digital signals.

For high-speed SPI or other timing-sensitive digital interfaces, verify that this type of level-shifting circuit is suitable for the required signal speed and electrical characteristics.

Key Features

• 4 Bi-Directional Channels: Translate up to four digital signals
• Typical Use: 3.3V logic to 5V logic conversion
• ESP32 Compatible: Allows 3.3V ESP32 logic to interface with compatible 5V devices when a 5V supply is available
• Separate LV and HV Inputs: Requires both low-voltage and high-voltage supply references
• No Boost Converter: Does not generate 5V from a 3.3V supply
• Automatic Bi-Directional Operation: No direction-control pin required
• I2C Compatible: Particularly useful for bi-directional I2C signals
• Compact Size: Suitable for breadboards and embedded projects
• Model: BOB-12009

Technical Specifications

• Logic Channels: 4 bi-directional channels
• Typical Logic Conversion: 3.3V to 5V
• Low-Voltage Reference: Supplied through LV pin
• High-Voltage Reference: Supplied through HV pin
• Ground: Common ground required
• Level-Shifting Circuit: MOSFET-based bi-directional design
• Common Applications: I2C, UART and general digital I/O
• Board Dimensions: Approximately 13mm x 15mm
• Model: BOB-12009
• Included: 1 logic level converter module

Logic Level Converter vs. Voltage Boost Converter

This distinction is important when selecting a module for an ESP32 project.

This BOB-12009 translates logic signals between two voltage systems that already exist. It does not create the second voltage.

If your ESP32 project has both 3.3V and 5V available, this module can translate signals between those voltage levels. If your project has only a 3.3V supply and you need to power a 5V device, you will also need a boost converter or another module designed to generate 5V.

Shop Logic Level Converters at Vetco Electronics

The BOB-12009 is a compact solution for connecting compatible ESP32, Arduino, Raspberry Pi, sensors and other mixed-voltage digital electronics. Before selecting this module, confirm that your project provides both the low-voltage and high-voltage supplies required by the converter.