A method for simulating a response of a circuit to an ESD input stimulus applied to the circuit includes the steps of: receiving a description of the circuit into a circuit simulation program, the circuit including at least one mutual inductance element indicative of magnetic coupling in the circuit; generating a linear approximation of nonlinear elements in the circuit at respective DC bias points of the nonlinear elements; obtaining a frequency domain transfer function of the circuit; obtaining a time domain impulse response of the circuit as a function of the frequency domain transfer function; integrating the time domain impulse response to yield a step response of the circuit, the step response being indicative of a response of the circuit to the ESD input stimulus; and analyzing the step response of the circuit to determine whether the circuit will operate within prescribed parameters corresponding to the circuit.