Issue link: https://resources.pcb.cadence.com/i/1180526
PSpice User Guide DC analyses October 2019 485 Product Version 17.4-2019 © 1999-2019 All Rights Reserved. Overview of small-signal DC transfer The small-signal DC transfer analysis calculates the small-signal transfer function by transforming the circuit around the bias point and treating it as a linear circuit. The small-signal gain, input resistance, and output resistance are calculated and reported. The digital devices themselves are not included in the small-signal analysis. A gate, for example, does not have a frequency response. Instead, all the digital devices hold the states that were calculated when solving for the bias point. However, for N and O devices in the analog/digital interface subcircuits, the analog side has a well-defined linear equivalent. To calculate the small-signal gain, input resistance, and output resistance 1. In the Bias Point analysis type, select Calculate small-signal DC gain (.TF). 2. Specify the value for either an output voltage or the current through a voltage source in the To Output variable text box. For example, entering V(a,b) as the output variable specifies that the output variable is the output voltage between two nets, a and b. Entering I(VDRIV) as the output variable specifies that the output variable is the current through a voltage source VDRIV. 3. Specify the input source name for Calculate small-signal DC gain (.TF) section. The gain from the input source to the output variable is calculated along with the input and output resistances. For example, if you enter V(OUT2)as the output variable and V1 as the input source, the input resistance for V1 is calculated, the output resistance for V(OUT2) is calculated, and the gain from V1 to V(OUT2) is calculated. All calculations are reported to the simulation output file.