A circuit for protecting an electronic device including a differential
nulling avalanche clamp circuit (200, 300) and method of using the
circuit in an electronic system (100) to limit radio frequency overdrive.
The electronic system (100) includes a surge clamp (130) coupled to
dissipate an electrical surge effect of a first frequency from a noise
sensitive node (140) and a ring wave clamp (120) coupled to dissipate an
electrical surge effect of a second frequency from the noise sensitive
node (140). The ring wave clamp circuit (200, 300) includes a first
bipolar junction transistor (210, 310), a second bipolar junction
transistor (220, 320) coupled to the first bipolar junction transistor
(210, 310), and a resistive circuit (230, 330, 340) coupled to the first
and second bipolar junction transistors (210, 220, 310, 320). A method of
using the electronic system (100) in a device to limit radio frequency
overdrive includes the steps of driving an output node with the radio
frequency signal subject to overdrive effects (410), clamping a first
order overdrive effect on a first node using a first clamp circuit (420),
and clamping a second order overdrive effect on the first node using the
differential nulling avalanche clamp circuit (430).