An analysis of bipolar breakdown and its application to the design of ESD protection circuits

Analytical expressions for the breakdown voltage of an NPN with a resistively grounded base, both with and without the Zener diode trigger which is used in a common ESD protection circuit, are presented for the first time. The results are used to explain anomalous behavior in the I-V curve of the protection circuit, and to achieve a more efficient ESD protection circuit design.