Simulation Methodology for Analysis of Substrate Noise Impact on Analog / RF Circuits Including Interconnect Resistance

TL;DR

This paper introduces a new simulation methodology that considers parasitic interconnect resistance to analyze substrate noise effects on analog/RF circuits, highlighting the importance of on-chip interconnects.

Contribution

The paper presents a novel simulation approach that includes parasitic resistance effects, enabling detailed analysis of substrate noise impact on high-frequency circuits.

Findings

Resistive coupling causes ground bounce and frequency modulation in VCOs.

On-chip interconnects play a crucial role in substrate noise impact.

Methodology helps identify devices needing shielding or topology changes.

Abstract

This paper reports a novel simulation methodology for analysis and prediction of substrate noise impact on analog / RF circuits taking into account the role of the parasitic resistance of the on-chip interconnect in the impact mechanism. This methodology allows investigation of the role of the separate devices (also parasitic devices) in the analog / RF circuit in the overall impact. This way is revealed which devices have to be taken care of (shielding, topology change) to protect the circuit against substrate noise. The developed methodology is used to analyze impact of substrate noise on a 3 GHz LC-tank Voltage Controlled Oscillator (VCO) designed in a high-ohmic 0.18 $\mu$m 1PM6 CMOS technology. For this VCO (in the investigated frequency range from DC to 15 MHz) impact is mainly caused by resistive coupling of noise from the substrate to the non-ideal on-chip ground interconnect, resulting in analog ground bounce and frequency modulation. Hence, the presented test-case reveals the important role of the on-chip interconnect in the phenomenon of substrate noise impact.