.DC — Perform a DC Source Sweep Analysis

This performs a DC analysis while sweeping the DC value of a source. It is useful for computing the DC transfer function of an amplifier or plotting the characteristic curves of a transistor for model verification.

Syntax:

.dc <sweep1> [<sweep2> [<sweep3>]]

<sweep1>, <sweep2>, and <sweep3> can be:

[<oct, dec, lin>] <srcnam> <start> <stop> <incr>

The <srcnam> is either an independent voltage or current source that is to be swept. The source is swept from <start> to <stop>. The number of steps is defined with the keyword oct, dec, or lin (which is the default) and <incr> according to the following table:

Keyword	incr
oct	No. of steps per octave
dec	No. of steps per decade
lin	Step size

<srcnam> list <value1> [<value2> [<value3> [ ... ]]]

The source is assigned values from the given list.

The source is assigned values read from the given file. This file can contain comments like a regular netlist. The numbers must be separated by whitespace or commas.

In the following example, the default BSIM3v3.2.4 characteristic curves are plotted:

* Example .dc sweep
M1 2 1 0 0 nbsim
Vgs 1 0 3.5
Vds 2 0 3.5
.dc Vds 3.5 0 -0.05 Vgs 0 3.5 0.5
.model nbsim NMOS Level=8
.save I(Vds)
.end