eldo_user

Optimization
Design Objectives
Design Objectives
This topic describes how to specify the design objectives to be considered by the .OPTIMIZE
command when performing an optimization.
Design objectives represent a desired behavior, for example a required frequency response for a
filter circuit. The optimizer adjusts the design variable parameters of the circuit (such as resistor
or capacitor values, the current gain (β) value of a transistor, widths and lengths of a MOSFET)
to meet the desired behavior. They are specified using .EXTRACT statements with additional
optimization parameters, or for more complex objectives the .OBJECTIVE command
(dedicated to optimization) can be used. For example, the objective of fixing the input power
matching of a Low Noise Amplifier (LNA) at a frequency of 2.4GHz to -15 is specified as:
.EXTRACT AC LABEL=S11_dB@2.4GHz
+ YVAL(SDB(1,1),2.4G)
+ GOAL=-15
This section covers:
Specifying Design Objectives Using .EXTRACT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 604
Specifying Design Objectives Using .OBJECTIVE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 608
Types of Design Objective. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 610
Design Objectives for Multi-Point Simulation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 618
Scaling Design Objectives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 621
Eldo® User's Manual, 15.3 603