TXS0108E 8-Channel Bidirectional Logic Level Converter - High Speed 3.3V to 5V

Specifications

• Logic IC: TXS0108E

• Channel Count: 8 Independent Bidirectional Channels

• Low-Voltage Side (VA): 1.2V to 3.6V DC

• High-Voltage Side (VB): 1.65V to 5.5V DC

• VCCA to VCCB Constraint: VCCA must be <= VCCB

• Max Data Rate (Push-Pull): 110 Mbps

• Max Data Rate (Open-Drain): 1.2 Mbps

• Output Enable (OE): Active High (Referenced to VCCA)

• Pin Spacing: Standard 2.54mm (0.1 inch) pitch

• Dimensions: 26mm x 16mm

Key Applications and Projects

• Raspberry Pi Interfacing: Protecting the Pi's fragile 3.3V GPIO pins when reading data from standard 5V Arduino-ecosystem ultrasonic sensors or relays.

• SD Card Readers: Stepping down standard 5V microcontroller logic to the strict 3.3V logic required by MicroSD cards for high-speed SPI data logging.

• Complex I2C/SPI Buses: Acting as a central hub to safely daisy-chain 1.8V, 3.3V, and 5V devices onto the same communication bus.

Unlock New Capabilities (Project Evolution) The 32-Bit Arcade Cabinet Brain Swap: Are you restoring a vintage 1980s arcade cabinet? The original mechanical coin mechs, heavy-duty joysticks, and illuminated buttons all operate on harsh 5V to 12V logic pulses. If you try to wire these directly into a modern 3.3V Raspberry Pi running RetroPie, you will destroy the Pi instantly. Evolve your restoration! By routing all those legacy 5V signals through the B-side of the TXS0108E, the module will flawlessly step them down to clean, safe 3.3V signals on the A-side. Your modern microcontroller can now read decades-old hardware with zero latency and absolute safety!

PAckage Incudes

• 1 x TXS0108E 8-Channel Logic Level Converter Module

• 2 x 10-Pin Straight Male Headers (Unsoldered)

FREQUENTLY ASKED QUESTIONS (FAQ)

1. What does this module do? It acts as a digital translator between two electronic devices that speak at different voltages. It takes a low-voltage signal (like 3.3V) and boosts it to a high voltage (like 5V), or takes a 5V signal and safely steps it down to 3.3V.

2. What does "Bidirectional" mean? It means data can flow in both directions simultaneously on any channel. It automatically senses if a 3.3V device is sending data to a 5V device, or if a 5V device is sending data back to the 3.3V device, without needing a dedicated "direction switch" pin.

3. What is the difference between Port A (VA) and Port B (VB)? Port A (VA) is the low-voltage side. Port B (VB) is the high-voltage side. VCCA must always be a lower voltage than VCCB.

4. Can I hook up 5V to Port A and 3.3V to Port B? No! Doing this violates the physical architecture of the TXS0108E chip. Port A must always be the lower voltage side. Reversing this will cause the module to fail or overheat.

5. What is the "OE" pin for? OE stands for Output Enable. To make the module work, this pin must be pulled HIGH (connected to your VCCA voltage). If you pull it LOW (to Ground), the chip disables all pins, effectively disconnecting the two sides from each other.

6. Do I need to connect grounds on both sides? Yes. You must connect the ground from your 3.3V circuit to the GND pin on Port A, and the ground from your 5V circuit to the GND pin on Port B to establish a common electrical reference.

7. Does this work with the I2C protocol? Yes, it fully supports open-drain protocols like I2C (SDA/SCL) and will easily handle the standard 100kHz and 400kHz speeds.

8. Does this work with the SPI protocol? Yes, this is where the TXS0108E excels. Because it can handle push-pull speeds up to 110 Mbps, it is ideal for high-speed SPI interfaces like SD card readers and TFT displays.

9. Does it work with UART (Serial TX/RX)? Yes, it works flawlessly for stepping down 5V UART signals to safely communicate with a 3.3V ESP8266 or ESP32.

10. Is it compatible with a Raspberry Pi? Absolutely. It is the perfect companion for a Raspberry Pi, allowing its fragile 3.3V GPIO pins to safely interact with standard 5V modules.

11. Can I use this with 1.8V sensors? Yes. The VCCA side supports voltages down to 1.2V. You can supply 1.8V to VA, and 3.3V to VB, to bridge a 1.8V sensor to a 3.3V microcontroller.

12. Can this module step down analog signals (like audio or potentiometers)? No. This is strictly a digital logic level converter. It only understands HIGH (1) and LOW (0) states. It cannot translate variable analog voltages.

13. Does this chip have internal pull-up resistors? Yes, the TXS0108E features integrated pull-up resistors (typically around 40k Ohm) on all data pins.

14. Can I use this to power a 5V motor or relay directly? No. This module is designed to transfer data signals at very low currents (a few milliamps). It is not a power supply and will burn out immediately if you try to use a data pin to drive a motor or heavy load.

15. Why use this instead of a standard 4-channel BSS138 converter? The standard BSS138 converter is built using simple MOSFETs and external resistors. It is quite slow and struggles with fast SPI data. The TXS0108E is an active IC designed specifically for high-speed data integrity.

16. Are the header pins pre-soldered? No. The module ships with the two 10-pin male headers loose in the package. You will need a soldering iron to attach them to the board.

17. Is it breadboard compatible? Yes, once you solder the included headers onto the module, the 2.54mm pitch pins will plug perfectly into any standard prototyping breadboard.

18. What should I do if the module isn't translating signals? First, ensure that VCCA <= VCCB. Second, ensure that both Grounds are connected. Third, explicitly verify that you have tied the OE (Output Enable) pin to VCCA. If OE is floating or LOW, the module will not transmit.

19. Can I leave unused channels disconnected? Yes, you do not need to use all 8 channels. Unused channels can safely be left floating (unconnected).

20. Will adding this module introduce delay/latency into my circuit? Technically yes, as the signal must pass through silicon gates, but the propagation delay is measured in nanoseconds (billionths of a second). For microcontroller applications like Arduino or Raspberry Pi, this delay is completely imperceptible and irrelevant.