ACTreS: Analog Clock Tree Synthesis

TL;DR

This paper introduces ACTreS, a formal graph-theoretic approach and automated flow for designing clock trees in Sampled-Data Analog Circuits, leveraging digital clock tree synthesis tools to improve efficiency and reduce errors.

Contribution

It presents a novel formalism and automated design flow for analog clock trees, adapting digital CTS techniques for analog circuit applications.

Findings

Automated clock tree design reduces manual effort.

Flow successfully applied to a 0.18 micron ADC circuit.

Demonstrates feasibility of digital CTS tools in analog domain.

Abstract

This paper describes a graph-theoretic formalism and a flow that, to a great extent, automate the design of clock trees in Sampled-Data Analog Circuits (SDACs). The current practice for clock tree design of SDACs is a manual process, which is time-consuming and error-prone. Clock tree design in digital domain, however, is fully automated and is carried out by Clock Tree Synthesis (CTS) software. In spite of critical differences, SDAC clock tree design problem has fundamental similarities with its digital counterpart. We exploited these similarities and built a design flow and tool set, which uses commercial digital CTS software as an intermediate step. We will explain our flow using a 0.18 micron 10-bit 60 MHz 2-stage pipelined differential-input flash analog-to-digital converter as a test circuit.