This paper describes the Loop Compensator and Capacitor Decoupling Design Tool software for digital DC/DC converters. The DC/DC converter is modeled using a structural flow obtained using graph theory and switched Hamiltonian Differential Algebraic Equation models. These models are suitable for analysis in the time domain, which is especially useful for load transient simulations. Linear models that can be transformed to the frequency domain for analysis are derived from the Hamiltonian models. The duty cycle is included in the input signal vector, enabling full system analysis with respect to the system’s transfer functions: audio susceptibility, output impedance, and the control loop.