Beyond simulation: Finding floating nets in analog circuits with Insight Analyzer
Floating nets in analog power-down circuits are a hidden reliability risk in IC designs. When a circuit is disabled to save power, certain internal nodes can lose all connection to any defined voltage – leaving them “floating.” Over time, leakage currents cause these nodes to drift to unpredictable voltages, which can silently turn on transistors that should be off, route unregulated power to sensitive outputs or cause damage to the device. The dangerous part: conventional SPICE simulation almost never catches these defects because they only appear under specific power-down conditions that designers rarely simulate.
According to the Wilson Research Group / Siemens EDA Functional Verification Study, first-silicon success rates dropped to a historic low of 14% in 2024. Structural reliability issues, such as floating nets, are a significant contributor to this decline.
Siemens’ Insight Analyzer solves this problem by analyzing the circuit’s structure rather than simulating its behavior. This technical paper details the use of Calibre Insight Analyzer to detect these issues during the pre-layout schematic stage, providing a "structural signoff" that bridges the gap between design and silicon.
Insight Analyzer examines every net under every enable/disable configuration and flags any node that lacks a defined voltage path – without requiring a simulation testbench. We present a use case in which Insight Analyzer finds a floating net in an LDO voltage regulator, in seconds, from the pre-layout schematic.
What you'll learn:
- Why floating nets are a primary cause of silicon failure in modern analog designs
- The limitations of traditional SPICE simulation in detecting state-dependent defects
- How to use Calibre Insight Analyzer for early, static identification of floating nets
Who should read this:
- Analog design engineers
- Reliability verification engineers
- IC design and CAD managers
- Verification flow architects