3 Benefits of Hot-Swappable Isolated I²C

Digital signal isolation protects low voltage, logic-level subsystems from mid-to-high-voltage sensors, actuators, and transient events. In systems with long cables or in noisy environments, high voltage transients can occur and damage low-voltage circuitry. I2C-compatiable digital isolators, like ISO1640 and ISO1641, help protect low-voltage circuitry from high voltages, and their hot-swap capability combines bus dependability when adding or removing I2C nodes with isolation protection from undesired or unexpected voltage shifts.

By design, ISO1640 and ISO1641 isolated I2C devices have full “hot-swap” compliance and can help prevent the common modes of failure from using regular I2C devices without the following hot-swap feature:

1. Data corruption due to transients while plugging in the part
2. Loading the bus at every low to high bus transition if the supply is not present, as partially hot-swappable devices can
3. Excessive voltages on the I2C bus appearing on the local supply rail due to parasitic leakage paths if the part has non-failsafe ESD

Examples of how TI’s fully hot-swappable I2C devices outperform other devices to prevent some of the modes of failure listed above are demonstrated in the following section.