ESD Protection Circuits

This chapter discusses exemplar electrostatic discharge (ESD) protection circuit design techniques. ESD protection follows the same general principle for all integrated circuit (IC) pads, i.e., to discharge the large ESD transient current without overheating and to clamp the pad voltage to a low level to avoid voltage breakdown. In general, the ESD protection schemes for input pads can be used for output pads too. However, as stated before, good ESD protection must be IC‐specific, or tailored for each pad per its functional needs. For output pads, ESD protection has its uniqueness, such as, breakdown features and self‐protection. A forward diode‐string may be used for I/O ESD protection to meet the design specs of both ESD triggering and low ESD‐induced parasitic capacitance. For output ESD protection, the output buffer transistors may be modified for ESD self‐protection. Various ESD protection structures can be used as supply line power clamps.