TXS0108E 8-Channel Logic Level Converter Module

The TXS0108E is a popular 8-channel bidirectional logic level converter designed for interfacing devices with differing voltage levels.

The TXS0108E is a straightforward, robust module for interfacing digital systems running at different voltages, with ease of use thanks to its auto-direction sensing and speed capabilities. It’s widely used in maker and professional setups for connecting 1.8 V, 3.3 V, and 5 V logic domains—just be mindful of OE and pull-ups!

Features:

• 8‑bit bi‑directional translation (no direction-control signal needed) 
• Voltage support:
  • Port A (low) V_CCA: 1.4 – 3.6 V (typical: 1.8/3.3 V)
  • Port B (high) V_CCB: 1.65 – 5.5 V (typical: 3.3/5 V)
• High speed:
  • Push–pull: up to 110 Mbps
  • Open‑drain: up to 1.2 Mbps 
• No power sequencing required: either supply (A or B) can power up first 
• OE (Output Enable) pin:
  • Active‑high = outputs enabled
  • Active‑low = all channels go high‑impedance 
• Built‑in ESD protection: up to 2 kV HBM on A‑port 

? Pin & Board Layout

• VCCA, A1–A8, OE, GND, B1–B8, VCCB (20 pins total) 
• Dimensions ~26 × 16 mm; plated‑through‑hole headers for easy soldering 

⚙️ How It Works

• Push–pull signals: full‑duplex up to 110 Mbps.
• Open‑drain interfaces (e.g. I²C, 1-wire): works with internal pull-ups to each side; up to 1.2 Mbp
• Enable/OE logic: OE tied low disables translator (Hi‑Z); tie high (or VCCA) to enable. Defaults disabled via pull‑down resistor on many breakout boards 

✅ Typical Applications

• SPI / UART / GPIO bridging between 3.3 V and 5 V systems
• I²C bus translation (open‑drain auto‑direction sensing)
• Interfacing microcontrollers, sensors, SD cards, etc. 

?️ Wiring Example (e.g., RPi ↔ Arduino):

1. Connect RPi 3.3 V → VCCA and relevant A pins (A1-Ax).
2. Connect Arduino 5 V → VCCB and matching B pins.
3. Tie GND between both systems.
4. Connect OE to VCCA (3.3 V) to enable translator.
5. Connect your data lines: e.g., A1 ↔ B1, A2 ↔ B2, etc. 

⚠️ Notes & Limitations

• Not ideal for analog signals—designed for digital logic edges.
• Pull‑ups: internal ones for open‑drain lines; external pull‑ups may be needed for heavy loads or long wires.
• OE must never be left floating—tie it explicitly to avoid undefined behavior .
• Bidirectional auto-detect doesn’t work for all analog speeds—best for digital buses with moderate speeds.