User Tools

Site Tools


geda:example_hsm

Differences

This shows you the differences between two versions of the page.

Link to this comparison view

Both sides previous revision Previous revision
Next revision
Previous revision
Last revision Both sides next revision
geda:example_hsm [2006/05/08 15:55]
dhart_1951
geda:example_hsm [2012/03/06 04:18]
vzh Fixed example path
Line 1: Line 1:
 +====== Hierarchical SPICE model ======
 +Example of a hierarchical analog RF SPICE model in the:\\
 +**''​${prefix}/​share/​doc/​geda-gaf/​examples/​RF_Amp''​**\\
 +directory, where ''​${prefix}''​ is the installation prefix for gEDA on your
 +system (usually **''/​usr''​** or **''/​usr/​local''​**).
 +
 +<​code>​This README created 3.31.2003
 +
 +--------------------- ​ Contents of directories ​ -----------------------
 +
 +This directory holds the schematics and associated materials for a
 +SPICE model of Agilent'​s MSA-2643 bipolar amp.  The model was obtained
 +from Agilent'​s datasheet 5980-2396E. ​ The directory structure is as
 +follows:
 +
 +RF_Amp (base directory)
 +
 +MSA-2643.sch -- schematic of stuff inside device package (as shown in
 +p. 7 of datasheet. ​ Note that I have not included the transmission ​
 +lines in this schematic because no value of Z was included in the data
 +sheet. ​  (Yes, it's probably 50 ohms, but including them was a
 +sideshow compared to my main intent: build a hierarchical model of an
 +RF circuit.)
 +MSA-2643.cir -- netlisted circuit ready for SPICE simulation.
 +
 +Q1.sch -- schematic model of Q1 MSA-26 transistor shown on p. 8 of datasheet.
 +Q1.cir -- netlisted circuit holding .SUBCKT model of Q1.
 +
 +Q2.sch -- schematic model of Q2 MSA-26 transistor shown on p. 8 of datasheet.
 +Q2.cir -- netlisted circuit holding .SUBCKT model of Q2.
 +
 +README -- this file.
 +
 +Simulation.cmd -- a file holding SPICE analysis commands which is read
 +at simulation time by the SPICE simulator.  ​
 +
 +5980-2396E.pdf -- Agilent datasheet about the MSA-2643.
 +
 +
 +./model/
 +
 +BJTM1_Q1.mod -- text-based SPICE model of BJT1 used in Q1 .SUBCKT
 +DiodeM1_Q1.mod -- text-based SPICE model of diode M1 used in Q1 .SUBCKT
 +DiodeM2_Q1.mod -- SPICE model of diode M2 used in Q1 .SUBCKT
 +DiodeM3_Q1.mod -- SPICE model of diode M3 used in Q1 .SUBCKT
 +(similar files for Q2 models. . . .)
 +These models were obtained from parameters give in p. 8 of the datasheet.
 +
 +./sym/
 +
 +BJT_Model.sym
 +spice-subcircuit-IO-1.sym
 +spice-subcircuit-LL-1.sym
 +Q_Model.sym -- symbol pointing to lower level models placed on upper
 +level schematic.
 +
 +------------ ​ Usage of hierarchical spice models ---------------------
 +This project exemplifies construction of a hierarchical SPICE
 +simulation using gEDA.  The project is built in the following way:
 +
 +1.  Use a text editor to create .mod files containing SPICE models of
 +the transistors and diodes on p. 8 of the datasheet.  ​
 +
 +2.  Create Q1 and Q2 transistor model schematics using gschem. ​ Place
 +the .SUBCKT SPICE block on the schematic to alert the netlister that
 +the schematic is a lower level .SUBCKT for incorporation into other
 +schematics. ​ Place spice-IO pads on the schematic to instantiate the
 +IOs.  Make sure to number the spice-IO pads in the same order as you
 +wish them to appear in the .SUBCKT line in the .cir.
 +
 +3.  Generate the .SUBCKT netlist by saying:
 +
 +gnetlist -g spice-sdb -o Q1.cir Q1.sch
 +gnetlist -g spice-sdb -o Q2.cir Q2.sch
 +
 +4.  Create a symbol for Q1.cir and Q2.cir which will be dropped onto
 +the higher lever schematic. ​ Name the symbol Q_Model.sym. ​ Set the
 +symbol "​DEVICE"​ attribute = NPN_TRANSISTOR_subcircuit. ​ This causes
 +the netlister to use "​write-default-component"​ to write out the SPICE
 +line for the component. ​ Make sure that the "​REFDES"​ attribute is X?
 +and not Q? -- this enables the .SUBCKT file to be attached to the
 +device. ​
 +
 +5.  Create the higher layer schematic MSA-2643.sch. ​ Place
 +two copies of Q_Model.sym onto the schematic, corresponding to Q1 and
 +Q2.  Make Q1 point to its model by setting the following attributes: ​
 +
 +model-name: Q1_MSA26F
 +file: Q1.cir
 +
 +Do the same for Q2.
 +
 +6.  Create the rest of the higher layer schematic the usual way.  Make
 +sure to place a spice-include block on the schematic and point it to
 +"​Simulation.cmd"​. ​ Place any analysis commands (e.g. .DC, .AC, .TRAN,
 +etc.) into the file "​Simulation.cmd"​.
 +
 +7.  Netlist the higher layer design:
 +
 +gnetlist -g spice-sdb -o MSA-2643.cir MSA-2643.sch
 +
 +8.  The circuit may be simulated by any desired SPICE simulation
 +and analysis package, e.g. LTSpice.
 +
 +-------------------- ​ Contact ​ ----------------------------
 +Documentation and other materials relevant to SPICE simulation under
 +gEDA lives at http://​www.brorson.com/​gEDA/​SPICE
 +
 +For inquiries or bug reports, please contact me:
 +
 +Stuart Brorson
 +mailto:​sdb@cloud9.net
 +</​code>​
  
geda/example_hsm.txt ยท Last modified: 2014/04/18 11:50 by vzh