Stats

  • Locked Locked
  • Replies 4
  • Subscribers 125
  • Views 17293
  • Members are here 0
This discussion has been locked.
You can no longer post new replies to this discussion. If you have a question you can start a new discussion

Using OPTION SCALE for only a particuar instance in Virtuoso ADE

jdp721

Hi,

I am simulating a schematic in Virtuoso ADE.

Besides different constituent sub-circuits, the schematic also includes a netlist of a sub-circuit (associated using "spectre" symbol view), yielding a overall netlist like:

simulator lang=spectre
global 0
include "/designPackages/design_installer/scl/scl_pdk/design_kit/models/hspice/ts18sl_scl.lib" section=tt_18
include "/research1/user/scl180_analog/physical_verification/pex/temp/Ckt_block.pex.netlist"

......

// various sub circuit definitions:

subckt cmos_inv in out vdd vss
M0 (out in vss vss) n18 w=2 l=0.2 as=0.96 ad=0.96 ps=4.96 pd=4.96 m=1

......

// main schematic definition and simulation settings

......

simulatorOptions options reltol=1e-3 vabstol=1e-6 iabstol=1e-12 temp=25.0 tnom=27 scalem=1.0 scale=1e-6 gmin=1e-12 ......

......

Now the issue is that most of my sub-circuits defined here need the scale=1e-6; but, the sub-circuit defined in "Ckt_block.pex.netlist" doesn't require this scale (as all values in that netlist are actual ones).

Is there any way to use a local scale statement (like scale=1e+6) in Ckt_block.pex.netlist (but that shouldn't affect the scale used in the main schematic)?

Parents
  • Andrew Beckett

    That won't work, because the model files would only get included inside a subckt definition netlisted by the spectre netlister, which as this is a stopping view, won't happen. I see a couple of alternative ways forward:

    1. Create a wrapper layer around Comparator_ver2a. In other words, create a schematic (say called Comparator_wrapper) which instantiates Comparator_ver2a, and has the same symbol as Comparator_ver2a - simply wire through all the connections. Then in the MTS setup, you can add the  model file for Comparator_ver2a and scale=1.0 with Comparator_wrapper as the MTS block. Set the default scale in the simulation->options->analog as usual.
    2. Or, modify the pex netlist to include simulator options scale=1.0 within the subckt definition for Comparator_ver2a. You might have to bracket the options statement with simulator lang=spectre and simulator lang=spice if it's in SPICE syntax. Then for whatever level of hierarchy is above the Comparator_ver2a in your schematic, add that as an MTS block and just reference the model file using the form above (without specifying the scale on the form). Set the default scale in simulation->options->analog to 1e-6.

    With both of these approaches, it works (hopefully) because you're taking advantage of the fact that the subckt definitions are defined in a particular scope, rather than being globally defined.

    Hopefully this will work!

    Regards,

    Andrew.

Reply
  • Andrew Beckett

    That won't work, because the model files would only get included inside a subckt definition netlisted by the spectre netlister, which as this is a stopping view, won't happen. I see a couple of alternative ways forward:

    1. Create a wrapper layer around Comparator_ver2a. In other words, create a schematic (say called Comparator_wrapper) which instantiates Comparator_ver2a, and has the same symbol as Comparator_ver2a - simply wire through all the connections. Then in the MTS setup, you can add the  model file for Comparator_ver2a and scale=1.0 with Comparator_wrapper as the MTS block. Set the default scale in the simulation->options->analog as usual.
    2. Or, modify the pex netlist to include simulator options scale=1.0 within the subckt definition for Comparator_ver2a. You might have to bracket the options statement with simulator lang=spectre and simulator lang=spice if it's in SPICE syntax. Then for whatever level of hierarchy is above the Comparator_ver2a in your schematic, add that as an MTS block and just reference the model file using the form above (without specifying the scale on the form). Set the default scale in simulation->options->analog to 1e-6.

    With both of these approaches, it works (hopefully) because you're taking advantage of the fact that the subckt definitions are defined in a particular scope, rather than being globally defined.

    Hopefully this will work!

    Regards,

    Andrew.

Children
No Data

Community Guidelines

The Cadence Design Communities support Cadence users and technologists interacting to exchange ideas, news, technical information, and best practices to solve problems and get the most from Cadence technology. The community is open to everyone, and to provide the most value, we require participants to follow our Community Guidelines that facilitate a quality exchange of ideas and information. By accessing, contributing, using or downloading any materials from the site, you agree to be bound by the full Community Guidelines.