eldo_user

Eldo Netlist Setup
Subcircuits
• Or globally in the top level netlist:
.PARAM p3=5
X1 N1 N2 N3 MY_SUBCIRCUIT
The precedence of these parameter assignment methods is, in descending order, subcircuit
instantiation, internal subcircuit, subcircuit declaration which acts as a default only, and finally
global declaration.
Use option PARHIER to control the priorities for parameters.
Note
.PARAM assignments are order dependent within the netlist. Thus, a parameter value
assigned using the .PARAM command will only apply to subcircuits instantiated after this
.PARAM command. Therefore, for the below:
.SUBCKT INV
.PARAM p1=v0
.ENDSx1 ... inv
.param p1=v1
This is accepted, and p1 retains the value of v0 within x1 (when option PARHIER is set to
local).
Accessing Nodes Inside Subcircuit Instances from Outside
The following example illustrates how inner nodes may be accessed from outside of a subcircuit
instance in which they are defined.
.subckt inner n1 n2 n3
r1 n1 n3 1k
r2 n3 n8 4k
q27 n1 n7 n8 nbip
*...
.ends inner
.subckt outer n1 n2 n3 n4
q1 n1 n5 n6 pbip
*...
x1 n10 n12 vdd inner
*...
.ends outer
x13 n21 n25 n30 vdd outer
cmill1 x13.n1 x13.n5 1.2p
cmill2 x13.x1.n1 x13.x1.n5 0.9p
Where cmill1 is the Miller Capacitance of q1 located inside the subcircuit x13 and cmill2 is the
Miller Capacitance of q27 located inside x1 which in turn is located inside x13. Note that in this
example, the capacitances are declared from outside of the subcircuit definitions.
128
Eldo® User's Manual, 15.3