Modern designs have multiple operating modes (e.g., turbo mode vs. power-saving mode). Synopsys tools in 2021 allow for , ensuring that fixing a violation in one scenario does not violate timing in another. 4. Best Practices for 2021 Timing Closure
To prevent the optimization engine from over-restructuring logic that requires precise physical placement, use preservation commands.
By 2021, the focus shifted towards . As designs grow in complexity (7nm and below), managing thousands of constraints manually is error-prone. The 2021 workflow emphasizes:
set_input_delay -clock sys_clk 0.2 [all_inputs] set_output_delay -clock sys_clk 0.3 [all_outputs] Use code with caution. C. False Paths and Multicycle Paths synopsys timing constraints and optimization user guide 2021
While the core SDC syntax remains consistent, the 2021 user guide places increased emphasis on:
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This technical guide unpacks the foundational methodologies and implementation techniques outlined in the , focusing on Synopsys Design Constraints (SDC) generation, clock modeling, path exception handling, and synthesis optimization. 1. Understanding the Synopsys Timing and Optimization Flow Modern designs have multiple operating modes (e
These define how long external logic takes to deliver data to the chip ( Tincap T sub i n end-sub ) or accept data from it ( Toutcap T sub o u t end-sub
In a real silicon chip, clocks do not arrive at all registers perfectly or at the exact same time. You must model these imperfections using the following commands:
report_timing -delay_type max : Generates the detailed path calculation for your worst setup violations. As designs grow in complexity (7nm and below),
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Mastering timing closure is the most critical phase of modern digital integrated circuit design. As clock frequencies push into the gigahertz range and process nodes shrink to sub-nanometer levels, writing accurate timing constraints is no longer just an administrative task—it is a core architectural requirement.
If you are currently diagnosing a timing issue, tell me about your , the clock relationship involved, or the Synopsys tool you are running. I can help you write the exact Tcl commands to fix it. AI responses may include mistakes. Learn more Share public link
The create_clock command is the primary method to define design speed. create_clock -name sys_clk -period 1.0 [get_ports clk] Use code with caution.
# Tells the tool that external logic takes 1.2ns to present data at 'data_in' set_input_delay -max 1.2 -clock SYS_CLK [get_ports data_in] Use code with caution.