How do you integrate STA with other design tools, such as synthesis, simulation, and layout?

1 Synthesis and STA

Synthesis is the process of transforming a high-level description of the circuit, such as a hardware description language (HDL) code, into a gate-level netlist that consists of logic gates and interconnects. Synthesis also performs optimizations to reduce the area, power, and delay of the circuit. STA is used during and after synthesis to check the timing constraints and violations of the netlist, such as setup and hold times, clock skew, and slack. STA can also provide feedback to the synthesis tool to guide further optimizations or adjustments. For example, STA can identify critical paths that need more timing margin or less loading, and suggest changes in the gate sizing, placement, or logic restructuring.

2 Simulation and STA

Simulation is the process of testing the functionality and behavior of the circuit by applying input stimuli and observing output responses. Simulation can be performed at different levels of abstraction, such as behavioral, functional, or gate-level. Simulation can also model different aspects of the circuit, such as logic, timing, power, or noise. STA is used in conjunction with simulation to verify the timing accuracy and consistency of the circuit. STA can also complement simulation by providing faster and more comprehensive coverage of the timing scenarios and corner cases. For example, STA can analyze the worst-case and best-case delays of the circuit under different process, voltage, and temperature (PVT) variations, while simulation can verify the functionality and robustness of the circuit under specific PVT conditions.

3 Layout and STA

Layout is the process of arranging the physical components and interconnects of the circuit on a silicon substrate. Layout also involves routing, floorplanning, placement, and parasitic extraction. Layout affects the timing performance and reliability of the circuit, as it introduces parasitic capacitance, resistance, and inductance that can alter the signal propagation and integrity. STA is used before and after layout to evaluate the impact of layout on the timing characteristics and requirements of the circuit. STA can also provide input to the layout tool to optimize the layout design and minimize the timing violations. For example, STA can identify congested or noisy regions that need more spacing or shielding, and suggest changes in the routing, placement, or vias.

4 Here’s what else to consider

This is a space to share examples, stories, or insights that don’t fit into any of the previous sections. What else would you like to add?