ESD Protection of Failsafe and Voltage-Tolerant Signal Pins
This chapter helps circuit designers to gain a better understanding of the challenges that exist when failsafe (FS), or FS/voltage-tolerant (VTOL) electrostatic discharge (ESD) protection is requested and to provide a checklist of considerations in the upstream development phase for successful integration of their designs. Successful integration of such ESD protection requires addressing a list of integration challenges early in the development cycle along with considerations of input/output (I/O) performance and cost. As technology scales and the cost pressure for reduced area and high performance are considered, upstream co-design activities between the I/O design team and the ESD design team are important for integrating the ESD protection into the circuit topology and layout landscape. In many complementary metal-oxide semiconductor (CMOS) applications, the chip substrate plays an integral role in triggering the FS ESD protection, thus control of the interactions with nearby diffusions is critical to success.