Setting the Spectre FX Options Locally

By default, Spectre FX options are applied at the global level. However, you can set the following options locally for a subcircuit by using the subckt= option or for specific instances by using the inst= option. Wildcards are supported for subckt and inst.

Examples

Sets the option locally on subcircuit primitives:

.option sfx_speed=mx subckt=pll

.option sfx_preset=basemx subckt=[osc bandgap]

Sets the option locally on instances:

.option sfx_speed=lx inst=x1.x1

.option sfx_speed=ax inst=[x1.x2 x1.x3]

In post-layout simulations with flatten DSPF file, there is no design hierarchy. sfx_preset can apply to specific elements in a DSPF file, as shown below.

.option sfx_preset=baseax subckt=[pll] element=[*osc*]

.option sfx_preset=baseax subckt=[pll] element=[x1/x2/xosc*]

In these examples, pll is the subckt name defined in a DSPF file. *osc* or x1/x2/xosc* is the instance name in DSPF file. element=[*osc*] or element=[x1/x2/xosc*] applies the local option to all MOSFETs in the specified oscillator block.

Spectre FX Circuit Simulator User Guide
Product Version 23.1, September 2023