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  14 <em>Translations of this page are also available in the following languages:</em> <a href="geda-example_hsm.ru.html" class="wikilink1" title="geda-example_hsm.ru.html">Русский</a>.
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  17 <h1 class="sectionedit1" id="hierarchical_spice_model">Hierarchical SPICE model</h1>
  18 <div class="level1">
  19
  20 <p>
  21 Example of a hierarchical analog RF SPICE model in the:<br/>
  22
  23 <strong><code>${prefix}/share/doc/geda-gaf/examples/RF_Amp</code></strong><br/>
  24
  25 directory, where <code>${prefix}</code> is the installation prefix for gEDA on your
  26 system (usually <strong><code>/usr</code></strong> or <strong><code>/usr/local</code></strong>).
  27 </p>
  28 <pre class="code">This README created 3.31.2003
  29
  30 ---------------------  Contents of directories  -----------------------
  31
  32 This directory holds the schematics and associated materials for a
  33 SPICE model of Agilent&#039;s MSA-2643 bipolar amp.  The model was obtained
  34 from Agilent&#039;s datasheet 5980-2396E.  The directory structure is as
  35 follows:
  36
  37 RF_Amp (base directory)
  38
  39 MSA-2643.sch -- schematic of stuff inside device package (as shown in
  40 p. 7 of datasheet.  Note that I have not included the transmission
  41 lines in this schematic because no value of Z was included in the data
  42 sheet.   (Yes, it&#039;s probably 50 ohms, but including them was a
  43 sideshow compared to my main intent: build a hierarchical model of an
  44 RF circuit.)
  45 MSA-2643.cir -- netlisted circuit ready for SPICE simulation.
  46
  47 Q1.sch -- schematic model of Q1 MSA-26 transistor shown on p. 8 of datasheet.
  48 Q1.cir -- netlisted circuit holding .SUBCKT model of Q1.
  49
  50 Q2.sch -- schematic model of Q2 MSA-26 transistor shown on p. 8 of datasheet.
  51 Q2.cir -- netlisted circuit holding .SUBCKT model of Q2.
  52
  53 README -- this file.
  54
  55 Simulation.cmd -- a file holding SPICE analysis commands which is read
  56 at simulation time by the SPICE simulator.
  57
  58 5980-2396E.pdf -- Agilent datasheet about the MSA-2643.
  59
  60
  61 ./model/
  62
  63 BJTM1_Q1.mod -- text-based SPICE model of BJT1 used in Q1 .SUBCKT
  64 DiodeM1_Q1.mod -- text-based SPICE model of diode M1 used in Q1 .SUBCKT
  65 DiodeM2_Q1.mod -- SPICE model of diode M2 used in Q1 .SUBCKT
  66 DiodeM3_Q1.mod -- SPICE model of diode M3 used in Q1 .SUBCKT
  67 (similar files for Q2 models. . . .)
  68 These models were obtained from parameters give in p. 8 of the datasheet.
  69
  70 ./sym/
  71
  72 BJT_Model.sym
  73 spice-subcircuit-IO-1.sym
  74 spice-subcircuit-LL-1.sym
  75 Q_Model.sym -- symbol pointing to lower level models placed on upper
  76 level schematic.
  77
  78 ------------  Usage of hierarchical spice models ---------------------
  79 This project exemplifies construction of a hierarchical SPICE
  80 simulation using gEDA.  The project is built in the following way:
  81
  82 1.  Use a text editor to create .mod files containing SPICE models of
  83 the transistors and diodes on p. 8 of the datasheet.
  84
  85 2.  Create Q1 and Q2 transistor model schematics using gschem.  Place
  86 the .SUBCKT SPICE block on the schematic to alert the netlister that
  87 the schematic is a lower level .SUBCKT for incorporation into other
  88 schematics.  Place spice-IO pads on the schematic to instantiate the
  89 IOs.  Make sure to number the spice-IO pads in the same order as you
  90 wish them to appear in the .SUBCKT line in the .cir.
  91
  92 3.  Generate the .SUBCKT netlist by saying:
  93
  94 gnetlist -g spice-sdb -o Q1.cir Q1.sch
  95 gnetlist -g spice-sdb -o Q2.cir Q2.sch
  96
  97 4.  Create a symbol for Q1.cir and Q2.cir which will be dropped onto
  98 the higher lever schematic.  Name the symbol Q_Model.sym.  Set the
  99 symbol &quot;DEVICE&quot; attribute = NPN_TRANSISTOR_subcircuit.  This causes
 100 the netlister to use &quot;write-default-component&quot; to write out the SPICE
 101 line for the component.  Make sure that the &quot;REFDES&quot; attribute is X?
 102 and not Q? -- this enables the .SUBCKT file to be attached to the
 103 device.
 104
 105 5.  Create the higher layer schematic MSA-2643.sch.  Place
 106 two copies of Q_Model.sym onto the schematic, corresponding to Q1 and
 107 Q2.  Make Q1 point to its model by setting the following attributes:
 108
 109 model-name: Q1_MSA26F
 110 file: Q1.cir
 111
 112 Do the same for Q2.
 113
 114 6.  Create the rest of the higher layer schematic the usual way.  Make
 115 sure to place a spice-include block on the schematic and point it to
 116 &quot;Simulation.cmd&quot;.  Place any analysis commands (e.g. .DC, .AC, .TRAN,
 117 etc.) into the file &quot;Simulation.cmd&quot;.
 118
 119 7.  Netlist the higher layer design:
 120
 121 gnetlist -g spice-sdb -o MSA-2643.cir MSA-2643.sch
 122
 123 8.  The circuit may be simulated by any desired SPICE simulation
 124 and analysis package, e.g. LTSpice.
 125
 126 --------------------  Contact  ----------------------------
 127 Documentation and other materials relevant to SPICE simulation under
 128 gEDA lives at http://www.brorson.com/gEDA/SPICE
 129
 130 For inquiries or bug reports, please contact me:
 131
 132 Stuart Brorson
 133 mailto:sdb@cloud9.net</pre>
 134
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