Analog and mixed-signal circuit design demands high amounts of knowledge, expertise and intuition. To that purpose, it is not deniable electrical CAD tools play a crucial role assisting designers in such complex scenario. SPICE-like electrical simulators have been established through the years as the de facto standard for analog and mixed-signal circuit simulation. Such simulation programs work at low level circuit description dealing with explicit component instantiations and electrical connections between them with no possibilities of description at a higher level. In this work, a software tool partially addressing this issue is proposed. The developed tool allows the designer to simulate a signal flow graph (SFG) given its behavioral description. The proposed tool efficiently transforms a behavioral SFG description into a netlist suitable for SPICE. It also generates the required graphical commands for rendering the graph as well as the listing of node equations to be solved algebraically. In order to evaluate the tool, it has been applied to behaviorally describe a transient error and fault tolerant scheme applied to a Biquad filter. The tool has been proven to be efficient in terms of its capabilities for mixing structural and behavioral descriptions in a single netlist, as well as for its simplicity and usefulness when dealing with large linear systems, therefore validating the proposal.