SLUAAY3 September   2024 PCA9306 , TCA39306 , TCA9548A

 

  1.   1
  2.   Abstract
  3.   Trademarks
  4. 1Introduction
  5. 2TCA39306 Level Translation Example
    1. 2.1 What is the Hang Time Effect and Why Does the Hang Time Occur?
    2. 2.2 Implications of Hang Time in an I2C System
  6. 3Summary
  7. 4References

1 Introduction

The I2C bus often uses some type of passFET based design to allow level translation on the I2C bus. This can be in the form of an I2C controlled switch (such as TCA9548A) or I2C voltage translators (PCA9306 or TCA39306). I2C controlled switches can be used to control bus capacitance in a system or handle multiple targets with the same I2C address. I2C voltage translators can be used for voltage translation between two supply rails. These I2C devices typically use an internal switch defined as a passFET. The passFET provides a simple low-cost design for I2C bus switching and level shifting, but also introduces a short hanging effect which is defined as passFET hang time in this application note.