APPLICATION NOTE
3
Calculating the Total Loop Gain
Once the voltage gain and the current gain are calculated, the total loop gain can be determined by the
following relation:
1/T+1 = 1/Ti+1 + 1/Tv+1
Therefore,
T=((Ti+1)||(Tv+1)) - 1
where
x||y = 1/(1/x + 1/y) = xy/(x+y)
Figure 1: Symbol Graphic
The symbol contains the attribute VOLTS = 0. This parameter is used to pass the value of a global
parameter to the subcircuit. In the example circuit, the global parameter ACVAL is defined and the
attribute value of VOLTS is set to {ACVAL}. If a parameter value is not passed to the subcircuit, the
default value for VOLTS is then 0. The template for the symbol is as follows (as a single line):
X^@REFDES %A %B @MODEL PARAMS: ?VOLTS|VOLTS=@VOLTS||VOLTS=0|
