Global Standards for the Microelectronics Industry
NOTE Large transient currents will be clamped for positive cathode-to-anode voltages when driven into the avalanche breakdown region with one or more p-n junctions placed in series or parallel with each junction connected in the same direction. Large transient currents may also be clamped for negative cathode-to-anode voltages at significantly lower voltages with the typical forward-conducting characteristics of a single p-n junction (or of multiple p-n junctions connected in the same direction). The most common type of unidirectional ABD has a forward-conducting characteristic.
Unidirectional-conducting ABD Unidirectional-blocking ABD