Item specifics
Description
4-Channel 3.3V-5V Bidirectional Level Shifter Module Product Overview
This 4‑channel bidirectional level shifter module is designed to solve signal voltage mismatch between 3.3V and 5V systems. It supports UART, IIC, SPI, 1‑Wire, TTL, and other bus signals. The module features an onboard 3.3V LDO regulator (up to 150mA output), a power indicator LED, and input reverse polarity protection. No external 3.3V supply is needed – just connect the VCC and GND of both systems, and the module transparently shifts logic levels in both directions. Stable communication is supported up to 28800bps. Each of the four channels is a straight‑through path, shifting only the voltage level. Ideal for communication between 5V and 3.3V microcontrollers, 3.3V programmers with 5V MCUs, and 5V MCUs with 3.3V sensors.
4-Channel 3.3V-5V Bidirectional Level Shifter Module Core Features
4‑Channel Bidirectional Level Shifting： Four independent channels, each shifts 3.3V ↔ 5V automatically in both directions, supporting UART, IIC, SPI, 1‑Wire, TTL buses without direction control
Onboard 3.3V Regulator： Provides up to 150mA to power 3.3V devices from a 5V supply – eliminates need for an external 3.3V source
Reverse Polarity Protection： Input power protection prevents damage if VCC and GND are accidentally reversed
Power Indicator LED： Red LED lights when power is applied for at‑a‑glance status
High Baud Rate Support： Stable operation up to 28800bps, suitable for most serial communication needs (9600, 19200, 28800)
Simple Wiring： Clearly marked sides: 5V side (AVCC, AGND, ASCL, ASDA) and 3.3V side (BVCC, BGND, BSCL, BSDA) – connect accordingly
Level Shifter Only – Not a Regulator： Designed for small‑current signal conversion; do not use as a power regulator or transformer
Headers Not Soldered (Included)： Pin headers are provided but not soldered, allowing users to solder them in any orientation (straight or right‑angle) for flexible integration
4-Channel 3.3V-5V Bidirectional Level Shifter Module Applications
5V MCU to 3.3V MCU Serial Communication： e.g., Arduino (5V) talking to ESP32/STM32 (3.3V) over UART
3.3V Programmer to 5V MCU： Using a 3.3V logic USB‑to‑TTL adapter to program a 5V microcontroller
5V MCU to 3.3V Sensor Modules： Connecting 5V host to 3.3V IIC/SPI sensors (e.g., MPU6050, BMP280)
Raspberry Pi to 5V Arduino： Safely interface 3.3V Raspberry Pi GPIO with 5V Arduino
Any 3.3V/5V Bus Level Translation： IIC, SPI, 1‑Wire, UART – any scenario requiring voltage‑level matching
4-Channel 3.3V-5V Bidirectional Level Shifter Module Key Advantages
Bidirectional, No Direction Control Needed： Each channel automatically shifts both ways – no extra pin for direction control, simple hardware, software transparent
Integrated 3.3V Supply Powers External Devices： Onboard LDO provides up to 150mA for 3.3V peripherals, saving an external regulator
Reverse Polarity Protection for Safety： Accidental power reversal won’t damage the module – ideal for teaching and experimental environments
Broad Protocol Compatibility： Supports UART, IIC, SPI, 1‑Wire – one module covers most level‑shifting needs
Stable, High‑Speed Communication： Up to 28800bps, satisfying common baud rates (9600, 19200, 28800)
Four Channels Are Enough for Most Use Cases： Simultaneously support a full UART (TX/RX – 2 channels) plus an IIC (SCL/SDA – 2 channels), or a full SPI (MOSI/MISO/SCLK/CS – 4 channels)
Plug‑and‑Play： Simple wiring, no programming required – works as soon as power is applied
Headers Soldered by You for Flexibility： Included but unsoldered headers let you choose the best orientation (straight or right‑angle) for your project
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FAQ:
What is a 4‑channel bidirectional level shifter module and why is it needed?
This module is a compact board that safely translates logic signals between two voltage domains (typically 3.3 V and 5 V) across four independent channels. It uses low‑RDS(on) N‑channel MOSFETs (often the BSS138) and pull‑up resistors to achieve bidirectional level shifting without a direction control pin. It is essential when connecting a 3.3 V microcontroller (such as an ESP32, Raspberry Pi, or nRF52) to 5 V sensors, displays, or actuators that are not 5 V‑tolerant, preventing permanent damage to the low‑voltage device.
How does the bidirectional level shifter work without a direction pin, and how does it differ from a simple resistor divider?
The module uses a single N‑channel MOSFET per channel in a common‑gate configuration. The source connects to the low‑voltage side (3.3 V), the drain to the high‑voltage side (5 V), and each side has a pull‑up resistor to its respective supply. When a low level is driven on either side, the MOSFET’s internal body diode and channel conduction pull the other side low. When a high level is released, the pull‑up resistors restore the high level. Unlike a resistive divider, this active circuit provides true bidirectional translation, sharper rise/fall times, lower output impedance, and supports higher‑speed protocols like SPI and I2C far better than a passive resistor divider.
Which communication protocols does this module support, and can it handle I2C, SPI, and UART simultaneously?
The module is protocol‑agnostic—it simply translates the voltage levels of any digital signal. It supports I2C, SPI, UART, TTL serial, and general‑purpose GPIO. Since it has four independent channels, you can, for example, use two channels for I2C (SDA and SCL), one for a UART TX, and the fourth as a GPIO handshake line, all operating simultaneously. The module does not load the bus or interfere with the protocol timing as long as the signal frequency is within its bandwidth.
What is the maximum signal frequency this module can reliably translate, and what limits the speed?
With the BSS138 MOSFET and 10 kΩ pull‑up resistors commonly fitted, the module reliably handles frequencies up to about 200‑400 kHz. This is sufficient for standard I2C (100 kHz/400 kHz), most UART baud rates, and SPI clocks up to a few hundred kHz. The speed is limited by the RC time constant of the pull‑up resistor and the parasitic capacitance of the MOSFET and PCB traces. For high‑speed SPI (above 2 MHz), you should either replace the pull‑ups with lower‑value resistors (e.g., 1‑2 kΩ) or choose a dedicated active level‑shifter IC such as the TXB0104 or TXS0104E.
How does the reverse‑polarity protection on this module work, and what does it protect?
The module includes a series Schottky diode or a P‑channel MOSFET on the high‑voltage supply input. If you accidentally swap the 5 V and GND wires, the protection circuit blocks current flow, preventing damage to the MOSFETs, pull‑up resistors, and any connected devices. This is a valuable feature for prototyping, but it does not protect against applying a dangerously high voltage that exceeds the MOSFET’s maximum ratings.
The module has a “3.3 V out” pin. Can I use it to power a small external device or sensor?
Most versions of this module do not include an on‑board 3.3 V regulator. The “3.3 V” pin on the low‑voltage side is typically an input—you must supply a regulated 3.3 V from your microcontroller or system power rail. Some modules may incorporate a small LDO, but they are usually limited to 100‑200 mA. Check the board’s silkscreen carefully: if it is labelled “3.3 V out” and your board has a regulator, you can draw a very small load; otherwise, use a dedicated 3.3 V regulator for powering external components.
How should I connect I2C devices using this level shifter? Do I need additional pull‑up resistors?
Connect the SDA and SCL lines from the 3.3 V side to the L1‑L2 pins, and the corresponding 5 V side pins (H1‑H2) to the 5 V I2C bus. The module already includes 10 kΩ pull‑up resistors on both sides, which is generally sufficient for short I2C buses and standard speeds. If you have a long cable or multiple devices, the total bus capacitance may be too high, causing slow rise times. In that case, you can add lower‑value external pull‑ups (e.g., 4.7 kΩ) on the 5 V side. Do not add extra pull‑ups on the 3.3 V side unless you calculate the combined resistance, as this may exceed the MOSFET’s sinking capability.
Can I use this module to shift between 5 V and 1.8 V, or between other voltage pairs?
The module is designed for standard 3.3 V/5 V translation, but it can be adapted for other voltage pairs as long as the low‑voltage side is at least 1.8 V and the high‑voltage side does not exceed the MOSFET’s VDS rating (typically 20 V). The key requirement is that the low‑voltage supply must be lower than the high‑voltage supply. For 1.8 V‑to‑3.3 V translation, you can use the module, but the pull‑up resistors may need to be adjusted. For fully specified, multi‑voltage translation, consider a dedicated IC such as the TXS0108E.
How does this BSS138‑based module compare with an active level‑shifter IC like the TXB0104 or TXS0104E?
The BSS138 discrete MOSFET module is simpler, lower‑cost, and works well for moderate‑speed signals (up to a few hundred kHz). The TXB0104/TXS0104E are active integrated circuits that provide guaranteed performance up to tens of MHz, automatic direction sensing with very low propagation delay, and integrated edge‑rate control. They are better suited for high‑speed SPI or fast PWM signals, but they cost more and may have limitations with driving heavily capacitive loads. For most Arduino and basic I2C/SPI projects, the BSS138 module is fully adequate.
What are the most common use cases for this 4‑channel bidirectional level shifter module?
It is widely used to interface 3.3 V microcontrollers (ESP32, Raspberry Pi, Arduino Zero) with 5 V I2C sensors, SPI LCD displays, 5 V UART modules, and logic‑level MOSFET drivers. It is also used to safely connect 3.3 V and 5 V development boards together on a breadboard, protecting the lower‑voltage device from over‑voltage stress. Its small size, low cost, and bidirectional capability make it a staple in any embedded prototyping toolkit.