Sunday, 27 May 2018

Device Level Voltage Checks

1. Power Connections Scan   2. Level Shifters


Insight Analyzer checks for a wide variety of power connectivity issues, both at the device level and bigger picture level. Like gate voltage over stress, missing level shifters , PBTI / NBTI.

Power Connections Scan

The Max ratings group contains checks that compare predicted in-circuit operating voltages to the voltage parameters specified in Device Parameters for each device. The Appropriate use group contains checks that will find other types of voltage related problems.

Max ratings

  • MOSFET gates
    Checks for MOSFET transistor gate voltages that can exceed maximum Vgs, Vgd or Vgb.

 

  • MOSFET drain/source
    Checks for MOSFET transistor source and/or drain voltages that can exceed maximum Vsd, Vdb or Vsb.

 

  • Diodes, Resistors, Capacitors
    Checks for passive device primitives (not FET-based) where the voltage across the device can exceed maximum Vbr (for reverse-biased diodes) or Vmax (for resistors and capacitors).

 

Appropriate use

  • MOSFET leaking
    Check for MOSFET transistors that cannot fully turn off, i.e., Vg < Vs for a PFET and Vg > Vd for an NFET. A common example would be a low voltage device driving a high voltage device.

 

  • MOSFET gate over-driven
    Check for MOSFET transistor gate voltages that can driven above (Vg > Vb for PFETs) or below (Vg < Vb for NFETs) its own body voltage, yet is still within device maximum rating. This can indicate a missing level shifter, risk of PBTI/NBTI, other unintended crossings, etc.

 

  • MOSFET cap flipped
    Checks for MOSFET transistors configured as capacitors that can be upside down, i.e., Vg > Vb for PFETs or Vg < Vb for NFETs.

 

  • Diode forward-biased
    Checks for primitive diodes (not FET-based) that can be forward-biased.

 

  • Substrate invalid voltage
    Checks for MOSFET transistors where the substrate can be forward biased. Vd < Vb < Vs for PFETs and Vd > Vb > Vs for NFETs.

 

  • Substrate foreign rail
    Checks for MOSFET transistors where the substrate connection leads to a rail other than that used for it's source (PFETs) or drain (NFETs).

 

  • Substrate soft tied
    Checks for MOSFET transistors where the substrate is tied to a rail through a resistive path.

 

MOS Body & Well Ties

Analyzer checks the 4th, 5th, and 6th terminals of MOS devices, supporting triple well process. All relevant bias points are checked. These checks need only a minimum of setup, and are process independent.


Built in checks support the most common requirements of MOSFET bulk terminal ties. Insight Analyzer enforces PMOS and NMOS types separately, according to industry standard practice.

 

Analog : PBTI / NBTI

It also reports gate-over-bulk mismatch as PBTI / NBTI, transconductance shift. For analog functions, this is an important check.

 

Level Shifters


Insight Analyzer recognizes level shifters automatically. That means easy setup, and reduced false positives in voltage checking.

  • Detect missing level shifters, by voltage mismatch, domain (name) mismatch, and UPF power state combinations.
  • Review all existing level shifters, showing signal names and power domains.

Check that level shifters are used in the approved voltages they were designed for (optimal application).

 


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

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