SDAA569 October   2026 ISO6020 , ISO6021 , ISO6040 , ISO6041 , ISO6042 , ISO6420 , ISO6420-Q1 , ISO6421 , ISO6421-Q1 , ISO6440 , ISO6440-Q1 , ISO6441 , ISO6441-Q1 , ISO6442 , ISO6442-Q1 , ISO6462 , ISO6463 , ISOW6441

 

  1.   1
  2.   Abstract
  3.   Trademarks
  4. 1Introduction
  5. 2How to Determine if a Digital Isolator Has Overvoltage-Tolerant Inputs?
  6. 3The Benefits of Digital Isolators with Overvoltage-Tolerant Inputs
    1. 3.1 Accept Higher-Than-Supply Input Levels Safely
    2. 3.2 Simplify Interfacing Between Devices with Different Supplies or Power Sequences
    3. 3.3 Improve Robustness During Brown-Out Conditions
    4. 3.4 Reduce Power Consumption by Powering Down During Normal System Operation
    5. 3.5 Withstands Signal Overshoots Due to Parasitics
    6. 3.6 Preserve Signal Integrity by Avoiding Extra Filtering Networks During EMC Transients
    7. 3.7 Reduce Board Area Utilization
  7. 4Digital Isolators with Overvoltage Tolerant Inputs
  8. 5Summary
  9. 6References

5 Summary

Overall, overvoltage tolerant inputs on digital isolators provide several system-level design benefits by allowing inputs to safely accept signals that exceed the device supply voltage within specified limits. This capability simplifies interfacing between devices with different supply voltages or power sequences and can improve robustness during brown-out conditions and signal overshoots caused by parasitics. By reducing the need for external level-shifting, protection, and filtering networks, overvoltage tolerant inputs can preserve signal integrity during EMC transients, reduce component count and board area, and simplify the overall design. In addition, the ability to maintain valid input operation when the isolator supply is removed or powered down can enable power-saving strategies during normal system operation.

These benefits make overvoltage tolerant digital isolators particularly useful in industrial automation, PLCs, motor drives, and power-electronics applications, where multiple voltage domains, power-sequencing conditions, and transient events are common. By combining voltage-domain compatibility with robust isolation and protection, overvoltage tolerant inputs can help designers develop simpler, more compact, lower-power, and more robust systems while maintaining compliance with applicable safety and reliability requirements.