Tuesday, 20 November 2018

Leakage

1.Contention    2.High Impedance (High-Z)  


Unintended leakage is a common reliability risks in integrated circuits. But the conditions that lead to these risks can be difficult to find with simulation. Leakage is often caused by high-impedance nodes, or “floats”, and is of particular risk in low power or power off states.
Leakage can also be caused by contention As with float cases, contention may depend on state. But the symptoms can be missed by simulation, which depends on specific input stimulus.

Conditional Analysis

Insight Analyzer is the industry’s only tool that discovers conditional float and contention nodes by a process of reverse engineering.


Analyzer operates without specific stimulus. It identifies potential victims of floats and shorts, then works backwards to systematically disprove them, regardless of the conditions that may be required.
Conditional analysis covers situations such as:

  • Floating
  • Leaking
  • Shorts / Crowba

 

Contention

In some situations, current can shoot through from power to ground. The conditions that cause this may be missed during simulation. Perhaps the necessary input stimulus was not provided.
A static ERC / DRC tool can not achieve this kind of analysis.

 

 

Insight Analyzer finds cases of contention, where pull-down and pull-up paths are both on together.

In this example of a standard cell, the passgate controls are faulty, and it is possible to turn on both the internal and external passgates are once.


A contention violation includes back trace of the circuit state, out to the offending inputs that cause the contention.

 

High Impedance ( High-Z )

Cross-Domain Floats

In cross-domain situations, there is a risk of floating input due to off driver.
Insight Analyzer chases after a wide range of cross-domain float cases such as the examples shown here.
Logic keepers can hold an input and make it safe (no violation).
Isolation cells will provide valid protection only if the whole case meets criteria: Valid controls, proper domain assignments, appropriate topology (NAND, NOR, level shifter, etc).

 

Conditional Floats

A passgate multiplexer may have improper controls. If the logic decoder leaves an open state, the multiplexer output will float.
Insight Analyzer detects such cases, by investigating the controls.

 

   

Insight Analyzer finds cases of floating where driver can be off while the power turns off.


Insight Analyzer reports this case, with a listing of the node states that cause the float.
Driver can be powered same as receiver to make this circuit safe.

 


InsightEDA provides software to fill an unmet need in the Electronics industry.

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