Module 88 min

Cadence Tempus

Cadence Tempus signoff STA: MMMC views, Quantus parasitics, the report_timing flow, its common flow with Innovus, signal integrity and ECO. PrimeTime’s counterpart.

Cadence Tempus is Cadence's signoff STA tool, the counterpart to Synopsys PrimeTime. It reads the routed netlist, SPEF parasitics (typically extracted by Cadence Quantus), libraries and SDC, and signs off timing across all scenarios. Tempus shares a common flow and data model with the Innovus place-and-route tool, so ECOs pass cleanly back for implementation, and it is built for massively-parallel, distributed analysis of large designs.

The Tempus flow

1
Set up the design and views

Read the libraries, routed netlist and the MMMC view definition (modes + corners).

2
Read parasitics

Load the Quantus-extracted SPEF for each corner so net delays are signoff-accurate.

3
Constrain and propagate

Apply the SDC per mode and use the propagated clock.

4
Update and report

update_timing, then report_timing for setup and hold across the active views.

5
SI and ECO

Run signal-integrity analysis and generate a timing ECO for Innovus to implement.

tcl
read_lib sky130.lib
read_netlist top_routed.v ; read_def top.def
read_spef top.spef
read_sdc  top.sdc
set_analysis_view -setup {func_ss} -hold {func_ff}
update_timing
report_timing -late   ;# setup
report_timing -early  ;# hold

Concepts worth knowing

  • Common flow with Innovus, the same data model and constraints carry from place-and-route into signoff and back for ECOs.
  • Quantus extraction, Tempus signs off on Quantus SPEF, the Cadence golden extractor.
  • Massively parallel, Tempus is designed to distribute large multi-scenario runs across many cores/machines.
  • SI, GBA/PBA and ECO, like PrimeTime, it models crosstalk, offers path-based analysis, and drives an ECO flow.
CommandPurpose
read_netlist / read_defRead the routed design
read_spefLoad Quantus parasitics
read_sdc / set_analysis_viewConstraints + MMMC views
update_timingCompute timing
report_timing -late / -earlySetup / hold reports
Note

In short, Tempus is Cadence signoff STA: define MMMC views, read the netlist and Quantus SPEF, constrain and propagate, then report setup/hold across scenarios and drive ECOs back into Innovus. It is PrimeTime's counterpart in the Cadence flow.