Using the 8 Channel Logic Level Bi-directional Converter TXS0108E
Because some controllers, displays and sensors work on 5V while others work on 3.3V, many makers find that they need to perform level shifting to protect the 3.3V device from 5V.
The simplest and most common method of logic level shifting is a voltage divider but it’s not good for high speed transfers and it only works in one direction. That’s where this chip comes in. It can perform bidirectional level shifting and will auto-detect the direction.
This 8-bit noninverting translator uses two separate configurable power-supply rails. The A port is designed to track VCCA. VCCA accepts any supply voltage from 1.2 V to 3.6 V. The B port is designed to track VCCB. VCCB accepts any supply voltage from 1.65 V to 5.5 V. This allows for universal low-voltage bidirectional translation between any of the 1.2-V 1.5-V, 1.8-V, 2.5-V, 3.3-V, and 5-V voltage nodes. VCCA should not exceed VCCB. When the output-enable (OE) input is low, all outputs are placed in the high-impedance state. It’s s designed so that the OE input circuit is supplied by VCCA. To ensure the high-impedance state during power-up or power-down, OE should be tied to GND through a pulldown resistor; the minimum value of the resistor is determined by the current-sourcing capability of the driver.
1.2 V to 3.6 V on A Port and 1.65 V to 5.5 V on B Port (VCCA ≤ VCCB)
Converting from 5V to 3.3V
- VA connects to Arduino 3.3V power supply
- VB connects to Arduino 5V power supply
- GND connected to the two power supply grounds
- When Bx has TTL 5V input, Ax will get TTL 3.3V output
- Connect OE to 5V