spicemanual

# spicemanual - Concise SPICE Ihsan Djomehri Spring 1999 1...

This preview shows pages 1–3. Sign up to view the full content.

Concise SPICE Ihsan Djomehri, Spring 1999 1 Introduction to Circuit Simulation Developed at Berkeley in the 70s, SPICE has evolved into the tool of choice for circuit level simulation. This handout seeks to provide a concise, fairly comprehensive introduction to HSPICE (version 98.2 running on MIT’s Athena network) and the graphing utility AvanWaves. I credit the authors of previous manuals for their information. In essence, SPICE reads in a list (called the “SPICE deck”) of circuit nodes and the elements between them, generates a series of nodal equations, and solves for the voltages. The deck also contains statements identifying which mode(s) the circuit should solve for: DC, AC, or transient analysis. Words of caution: many hacks have been introduced into SPICE over the years; always check the output to make sure it is intuitively reasonable! 2 Creating a SPICE Deck To start on Athena, make a new directory for your SPICE stuff, then type “add hspice” to add the HSPICE locker. Begin by sketching out your circuit on paper, labeling each node with a number, naming each circuit element and assigning properties to them. Note that node 0 is always ground and there can’t be any floating nodes. Use emacs to edit any text file like test.sp that will become our SPICE deck. An * in front of any line causes it to be interpreted as a comment. Later on, we will be using the circuit schematic in Figure 1 as a demonstration. The general format for entering in a circuit element is a one-letter identifier merged with a name, space, the node numbers that connect it, space, the properties of the element. Numerical property values are always in SI units (meters, seconds, volts, etc…) but can be modified by a suffix letter that acts as a multiplier: Suffix: t g x k m u n p f Multiplier: 1e12 1e9 1e6 1e3 1e-3 1e-6 1e-9 1e-12 1e-15 Thus, for various circuit elements we write (you modify italics, <>s are optional): Voltage: V name N+ N- <qualifier> value Current: I name N+ N- <qualifier> value Resistor: R name N+ N- value Capacitor: C name N+ N- value Inductor: L name N+ N- value Diode: D name N+ N- model_name BJT: Q name Nc Nb Ne model_name

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
MOSFET: M name Nd Ng Ns Nb model_name L= value W= value <+ AD =value AS =value PD =value PS =value> where N+ , N- are node numbers from the positive to negative node; Nc , Nb , Ne are the collector, base, and emitter node numbers of a bipolar transistor; Nd , Ng , Ns , Nb are the drain, gate, source, and body node numbers of a MOSFET; model_name refers to a user specified element model; L, W are the length and width of a MOSFET; AD, AS are the areas of the drain and source to body interface, while PD, PS are their perimeters.
This is the end of the preview. Sign up to access the rest of the document.

## This note was uploaded on 07/20/2009 for the course CSAIL 6.012 taught by Professor Prof.cliftonfonstadjr. during the Fall '03 term at MIT.

### Page1 / 7

spicemanual - Concise SPICE Ihsan Djomehri Spring 1999 1...

This preview shows document pages 1 - 3. Sign up to view the full document.

View Full Document
Ask a homework question - tutors are online