Abstract

Overvoltage tolerant inputs are digital isolator input pins that can safely accept logic signals at voltages higher than the isolator’s input-side supply. Digital isolators with overvoltage tolerant inputs, such as ISO6441 and ISO6041, provide several system-level benefits, including safe operation with higher-than-supply logic levels, simplified interfacing between devices with different supply voltages or power sequences, and improved robustness during brown-out conditions. They can also withstand signal overshoots caused by parasitics, maintain signal integrity during EMC transients without requiring additional filtering networks, and enable the isolator to be powered down during portions of normal system operation to reduce power consumption. By reducing the need for external protection and filtering components, overvoltage tolerant inputs can also help minimize board area. This application note reviews these benefits and discusses implementation considerations for digital isolators with overvoltage tolerant inputs.