SUPERCRYSTAL

SuperCrystal is a program for quick yet reasonably accurate simulation of MOS VLSI circuits. SuperCrystal divides the time axis into time steps. In each time step, a circuit is subdivided into subcircuits, each of which is approximated by a linear RC network. Single exponential approximations to node waveforms in the RC network are then calculated using a linear time algorithm.

SuperCrystal is an event-driven simulator. The order in which the subcircuits are evaluated exploits dependency relationships between subcircuits: as far as possible, a subcircuit is evaluated after all its ancestors in the dependency graph have been evaluated. SuperCrystal uses the Schichman-Hodges transistor model with threshold-voltage correction for substrate bias and correction for channel-length modulation.

SuperCrystal supports two simulation modes. In the steady-state simulation mode, an initial solution is obtained at time t = 0. In the transient simulation mode, the user is allowed to specify an arbitrary number of transients to be applied, and SuperCrystal will then obtain piecewise-exponential approximations to voltages at all nodes of the circuit. In addition, the user may specify "watched" nodes, and SuperCrystal will report the piecewise-exponential waveforms obtained for these nodes. SuperCrystal has been used to analyze several MOS circuits, including both large and small sequential and combinational circuits. Results indicate that the program is accurate in comparison with SPICE and several orders of magnitude faster.

SuperCrystal accepts three input formats: its own internal format, the Magic layout system extraction-output format, and a restricted version of the SPICE input format.

The tape includes the source code for a utility "scdisp" that translates SuperCrystal, SPICE, and RELAX2 output data into various forms suitable for plotting and printing.

Documentation Included with the Program:

1. User's Guide (includes Installation Notes). Available separately for $2.50
2. A. Raghunathan and C. D. Thompson, Signal Delay in RC-Trees with Charge Sharing and Leakage (UCB/CSD 85/243, June 1985). Available separately for $2.50
3. R. L. Bauer, A. P.-C. Ng, A. Raghunathan, M. W. Saake, and C. D. Thompson, "Simulating MOS VLSI Circuits Using SuperCrystal," Proc. VLSI, Vancouver, Canada, 1987. Available separately for $2.50

Foreign Distribution: Yes