Issue link: https://resources.pcb.cadence.com/i/1180526
PSpice User Guide Digital device modeling October 2019 389 Product Version 17.4-2019 © 1999-2019 All Rights Reserved. DIGMNTYSCALE This option computes the minimum delay when a typical delay is known, using the formula: TPxxMN = DIGMNTYSCALE ⋅ TPxxTY DIGMNTYSCALE defaults to the value 0.4, or 40% of the typical delay. Its value must be between 0.0 and 1.0. DIGTYMXSCALE This option computes the maximum delay from a typical delay, using the formula TPxxMX = DIGTYMXSCALE ⋅ TPxxTY DIGTYMXSCALE defaults to the value 1.6. Its value must be greater than 1.0. When a typical delay is unspecified, its value is derived from the minimum and/or maximum delays, in one of the following ways. If both the minimum and maximum delays are known, the typical delay is the average of these two values. If only the minimum delay is known, the typical delay is derived using the value of the DIGMNTYSCALE option. Likewise, if only the maximum delay is specified, the typical delay is derived using DIGTYMXSCALE. Obviously, if no values are specified, all three delays will default to zero. Treatment of unspecified timing constraints The remaining timing constraint parameters are handled differently than the propagation delays. Often, data books state pulse widths, setup times, and hold times as a minimum value. These parameters do not lend themselves to the extrapolation method used for propagation delays. Instead, when one or more timing constraints are omitted, the simulator uses the following steps to fill in the missing values: ■ If the minimum value is omitted, it defaults to zero.