2021: Synopsys Timing Constraints And Optimization User Guide

The Synopsys Timing Constraints and Optimization User Guide 2021 is a comprehensive resource for digital designers, verification engineers, and design managers. By mastering timing constraints and optimization techniques, designers can create high-performance, low-power, and area-efficient designs. The guide provides best practices, key features, and solutions to common challenges, helping designers to get the most out of Synopsys' EDA tools.

The logic gates and interconnect wires that delay the signal.

Synopsys tools use Design Constraints (SDC) syntax to communicate design intent to the synthesis and implementation engines. SDC files constrain three primary elements: area, power, and timing. Of these, timing constraints are the most complex.

In ideal simulation, clock edges arrive instantaneously across every flip-flop. In real silicon, physical factors degrade the clock signal. Synopsys provides specific commands to model these real-world effects during synthesis and pre-layout STA. Clock Uncertainty synopsys timing constraints and optimization user guide 2021

To efficiently achieve timing closure, engineers should follow these best practices:

: Techniques like adaptive retiming, register merging, and FSM optimization. High-Level Optimization : Datapath and multiplexer mapping strategies. 7. Analysis and Management Reporting Constraints report_timing check_timing report_constraint to verify the design. Managing Large Designs

While slight over-constraining can help achieve closure, extreme over-constraint can lead to excessive runtime and poor area/power results. 4. Advanced Optimization Techniques The Synopsys Timing Constraints and Optimization User Guide

# Maximum output delay for external setup compliance set_output_delay -max 0.4 -clock SYS_CLK [get_ports OUT_DATA] # Minimum output delay for external hold compliance set_output_delay -min -0.1 -clock SYS_CLK [get_ports OUT_DATA] Use code with caution. 4. Timing Exceptions and Control

For detailed command syntax and specific tool behaviors, refer to the documentation for the 2021.03SP1 or later versions.

Many designs use , which are clocks derived from a master clock. These are common in designs with clock dividers. The user guide covers how to define generated clocks with the create_generated_clock command, specifying the relationship between it and its source master clock, including division factors, phase shifts, and duty cycle changes. Getting generated clocks correct is crucial for accurate multi-clock domain analysis. The logic gates and interconnect wires that delay the signal

set_output_delay -max 0.5 -clock SYS_CLK [get_ports data_out] set_output_delay -min -0.2 -clock SYS_CLK [get_ports data_out] Use code with caution. 4. Advanced Timing Exceptions

Before physical placement occurs, Design Compiler estimates interconnect capacitance and resistance using statistical wire load models. set_wire_load_model -name "tsmc16_wl30" Use code with caution. Design Rule Constraints (DRVs)