Synopsys Timing Constraints And: Optimization User Guide 2021

Synopsys Timing Constraints and Optimization User Guide (often associated with the Design Compiler or PrimeTime toolsets)

1. create_clock: Creates a clock constraint. Example: create_clock -name clk -period 10 -waveform 0 5
2. set_input_delay: Sets the input delay constraint. Example: set_input_delay -max 3 -clock clk [get_ports input_port]
3. set_output_delay: Sets the output delay constraint. Example: set_output_delay -max 2 -clock clk [get_ports output_port]
4. set_max_delay: Sets the maximum delay constraint. Example: set_max_delay -max 10 -from [get_ports input_port] -to [get_ports output_port]

The Synopsys Timing Constraints and Optimization User Guide is a primary reference for digital designers using tools like Design Compiler and PrimeTime to achieve timing closure. The guide covers the creation and management of Synopsys Design Constraints (SDC), which are essential for guiding synthesis and place-and-route tools to meet performance, area, and power goals.  Core Timing Constraints  synopsys timing constraints and optimization user guide 2021

Defining Timing Constraints in Four Steps - 2025.1 English - UG949 create_clock : Creates a clock constraint

A. System Interface Constraints

• Create Clock (create_clock): Defines the ideal clock waveform (period, waveform, name). This is the heartbeat of the design.
• Generated Clock (create_generated_clock): Essential for PLLs and clock dividers. It establishes the relationship between a master clock and a derived clock, ensuring correct latency propagation.
• Input/Output Delays (set_input_delay / set_output_delay): These define the timing windows relative to the clock for signals entering or leaving the current block. The guide details how to specify max (setup) and min (hold) delays to model external environments accurately.

Common Challenges and Solutions

Create_generated_clock: Essential for clock dividers or PLL outputs. It ensures the tool understands the phase relationship between the master clock and its derivatives. The Synopsys Timing Constraints and Optimization User Guide

• Synopsys Timing Constraints and Optimization User Guide 2021.
• Synopsys Design Compiler User Guide.
• Synopsys PrimeTime User Guide.
• Synopsys Hsim User Guide.