# 10.5.3. Customizing netlister behavior with component fields¶

Default netlister behavior can be overridden by adding specific fields to a component. Suppose we have the follwing schematic.

Sample circuits used for demonstrating netlister customization via component fields.

All transistors are Q_NPN_BEC components from the device library. Because they are not defined in the default netlister configuration they are netlisted as subcircuits (with instance name prefixed by X). The Value filed is used as the subcircuit name.

In Q_NPN_BEC, collector, base, and emitter pins are numbered 3, 1, and 2 which means that base will be dumped as the first subcircuit pin, emitter as the second, and colelctor as the third. Therefore Q1 without any special fields defined will be netlisted as

xq1 (b1 0 c1) T2N2222


To netlist the pins in correct order (collector, base, emitter) we add a field named PinMap and set it to “3 1 2”. This will dump pin number 3 as the first subcircuit pin (thus collector will come first), followed by pins 1 and 2 (base and emitter). Now Q1 will be netlisted as

xq1 (c1 b1 0) T2N2222


To netlist it as a builtin bipolar transistor device (without adding the x prefix to device name) we must set the NamePrefix field to “Q”. This is what we did with Q2 which is netlisted as

q2 (c1 b1 0) T2N2222


To add parameters to the netlisted instance we must define the Parameters field and set it to the names of the parameters that will be dumped. The values of parameters can be set as additional fileds with parameter name for field name and parameter value for field value. To dump parameters “area” and “m” we must set the Parameters field to “area m”. If we now define the “area” and/or the “m” field they will be dumped in the netlist. Setting m to 4 and area to 8 (as in transistor Q3) will result in

q3 (c3 b3 0) T2N2222 param: m=4 area=8


Although this is fine for a subcircuit (where keyword “param:”) must be added it is not OK for a builtin bipolar transistor. To get rid of the “param:” keyword we must change the netlisting pattern by defining the OutPattern field (as in transistor Q4). By default unknown components are netlisted with the following pattern

#REF() (#PINS()) #MODEL() #PARAM() #PNV() #PV(Specification)


This means that first the correctly prefixed component name (#REF()) is dumped, followed by its pins in parenthesis ((#PINS())). Next the model name is dumped (#MODEL()) which is obtained from the Value field followed by the “param:” keyword (#PARAM()) which is dumped if any of the parameters listed in the Parameters field are defined as fields. This is followed by pairs of the form name=value (#PNV()). In the end the verbatim value of the Specification field (if defined) is added (#PV(Specification)).

To get rid of “param:” we drop #PARAM() from the pattern by setting the OutPattern field to

#REF() (#PINS()) #MODEL() #PNV() #PV(Specification)


This will dump Q4 which (has all the mentioned customizations) as

q4 (c4 b4 0) T2N2222 m=4 area=8


which is the correct way for netlisting a builtin bipolar transistor device.

Demo files for this section can be found here.