Issue link: https://resources.pcb.cadence.com/i/1180526
PSpice User Guide Digital device modeling October 2019 376 Product Version 17.4-2019 © 1999-2019 All Rights Reserved. Introduction The standard part libraries contain a comprehensive set of digital parts in many different technologies. Each digital part is described electrically by a digital device model in the form of a subcircuit definition stored in a model library. The corresponding subcircuit name is defined by the part's MODEL attribute value. Other attributes—MNTYMXDLY, IO_LEVEL, and the PSPICEDEFAULTNET set—are passed to the subcircuit, thus providing a high-level means for influencing the behavior of the digital device model. Generally, the digital parts provided in the part libraries are satisfactory for most circuit designs. However, if your design requires digital parts that are not already provided in the PSpice part and model libraries, you need to define digital device models corresponding to the new digital parts. A complete digital device model has three main characteristics: ■ Functional behavior: described by the gate-level and behavioral digital primitives comprising the subcircuit. ■ I/O behavior: described by the I/O model, interface subcircuits, and power supplies related to a logic family. ■ Timing behavior: described by one or more timing models, pin-to-pin delay primitives, or constraint checker primitives. These characteristics are described in this chapter with a running example demonstrating the use of gate-level primitives.