Friday, 18 October 2013

IR Drop Analysis using Redhawk - Overview

IR Drop Analysis using Redhawk:

Redhawk performs several types of power analysis on a circuit.
  • Static Voltage (IR) drop with average cycle currents
  • Dynamic Voltage drop with worst-case switching currents
  • Electromigration (EM) Analysis
  • Critical path and clock tree impacts
Redhawk Capabilities:
 As discussed above Redhawk is used to perform EM, IR and transient analysis on power grid. Redhawk is available in different modes. They are
1. Static Mode
2. Dynamic Mode
3. Transient Mode

1. Static Mode: 
 In static mode, Redhawk can perform EM, IR drop analysis. In this mode the tool analyzes average IR Drop and EM in the design.

2. Dynamic Mode:
In Dynamic mode, Redhawk analyzes peak IR drop in the design during functional mode using Vectorless algorithm or VCD. It can also analyze peak IR drop in the design during scanning mode using Vectorless or VCD.

3. Transient Mode:
In Transient mode, Redhawk can perform power up and power down analysis. It analyses peak rush current during turn-on, power grid turn-on time.

Inputs for Redhawk :

  • . LEF
  • . DEF
  • . LIBS
  • . TECH
  • . ploc
  • . GSR
  • . <design>.timing
  • APL files ( cell.spcurrent, cell.cdev)
LEF - Library Exchange Format :
This is a industry standard format that has the information related to pin description and boundaries of the block /instances in the design.

DEF - Design Exchange Format :
This contains logical and physical connectivity between different instances and blocks in the design.

LIB - Synopsys liberty format:
This has several electrical and logical properties for a cell like: input and output pin properties, information on distributing power among the different power pins, internal energy of the cell, cell functionality information, etc.

SPEF - Standard Parasitic Exchange Format:
This file contains the parasitic (RC values) associated with each nets in the design.

It contains Pad location information based on Full-chip Floorplan.

Redhawk Tech file:
It contains Resistance information for all interconnect layers, EM limit information for all interconnect layers, Interconnect Stack information.

APL Files:
It Contains Current Profile characterization data for each standard cell, Intrinsic decap characterization data for each standard cell, Piecewise linear cap characterization data for each standard cell.

It contains STA Timing Information From Primetime. It is Recommended for Static analysis-provides accurate transition times and instance frequency. It required for Dynamic –provides switching windows.

RedHawk outputs:
• IR voltage drop contour maps
• Electro-migration (EM) analysis
• Power density and average current maps
• Text report files of detailed static power, voltage, and current data
• Warnings and violations reports.

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