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AccuCell

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Who Buys Cell Characterization Software?

Commercial Libraries Users Who Do Not Have In-house Characterization Tool Characterize Different Process, Voltage or Temperature (PVT)

Library vendors usually charge $35k per corner and it takes as long as 2 months for them to deliver

Aggressive Use of Library in Designs Narrow timing guard-bands for worst-case corner True performance – save time by avoiding fixing phantom timing

problems Quality Assurance of library

Timing arc validation Accuracy (timing, power, capacitance, etc.)

Typical Designs High End ASICs – Networking, DSP, Graphics, Chip-sets, embedded

controllers

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Who Buys Cell Characterization Software? (cont’d)

Custom Library Users Who Already Have In-house Characterization Tools Expand Capability with Commercial Software for Accuracy and

Capability Design Cycle Reduction – their tools are too slow Performance, Power and Area Migration of Designs

Foundry to foundry Process to process

Typical Designs Microprocessors, DSPs, FPGAs, Structure Custom Designs Battery powered designs that need “end of life” corners (home grown char

tools/methodology)

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Cell Characterization Challenges

Extensive set-up Function Determination Vector Selection for Various Measurements Choosing points for the load and slope tables

Long Run Time Tsetup/Thold Long vector set

Accuracy Vector dependent Measurement techniques

Results Validation Tool Maintenance

Keep-up with formats and standards Change templates for new designs Scripts around SPICE not sufficient/efficient

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Conventional Approach Manual Function

Identification

Manual Description of Transactions

Convert Transactions to Vectors

Run Simulation

Extract Results

Build Model


Players in the Market

Customers Who Have Internally Developed Solutions Library Technologies - LibChar Synopsys - Star-MTB/Nanochar/Liberty NCX Magma - CellRater CR Nangate - Library Characterizer Altos - Liberate

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Internally Developed Solutions – Strengths

Perceived Competitive Advantage NIH-hard to replace

Optimized for Their Specific Needs “Acceptable” Shortcuts taken

Control Over Development Priorities New Features New Model Formats

Unlimited License Access May Support an Internal Simulator Trusted Results

Empirical, users have built working silicon with these tools

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Common in IDMs, Large COTs, and large IP Providers (Artisan/ARM, Virage)


Internally Developed Solutions – Weaknesses

High Cost of Ownership Dedicated programmers are needed to maintain and enhance code Or, if the teams no longer exist, there is no support and no future

Inflexible Enhancing for new technology, new requirements or external forces such as an

external fab, is difficult Many IDMs are now using external fabs of third party libraries for the first time-

this often renders their internal system obsolete! May not support industry standard simulators

Difficult to Use Regularly rely on established users to run it / train new users Often have poor error messages, sporadic documentation, and little support

No Q/A of Generated Models Relies on user history or programming team credibility to validate models

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Library Technologies’ LibChar – Strengths

Works like most home grown tools Aggressively priced Establish installed base in small Fabless accounts Functional Verification of All Cell Types Additional Product Offerings

Power optimization for library development Clock tree analysis Gate-level power analysis (competes with WattWatcher) Static Timing Analysis Block & Micro Characterization

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Library Technologies’ LibChar – Weaknesses

LibTech is a very small company Current focus is not Characterization – Will he stay in business?

Fixed Table Size (No Variable Model Sizes) Manual Job Distribution and Dependency Management No Automatic Model Verification No Manpower for Support and Services Software releases every month – hard for customers to manage Less accurate Not for custom cells No distribution channel Significant manual steps Script based solution with no IP Uses 3rd party simulation software

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Synopsys Star-MTB/Nanochar/Liberty NCX – Strengths

Large Existing Customer Base Low Cost When Purchasing HSPICE Unlimited Access (Based on Available HSPICE licenses) Functional Recognition Supports Advanced Sequential Cells Supports Verilog, VHDL/VITAL, LIBERTY

Custom model interface permits new model integration All model engines are provided as source code for customization

Model Q/A Incremental Characterization Automatic function extraction Automatic vector generation

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Synopsys Star-MTB/Nanochar/Liberty NCX – Weaknesses

Extensive manual setup Limited to simple cells Hard to Use; Requires Expert User to Generate Accurate Data No support for TLF, Spectre, or SmartSpice No Dependency Management Poor Throughput Parallelization available but doesn’t use commercial job schedulers

Job distribution interferes with commercial job schedulers Practical number of parallel CPUs is 5-10 (rapid performance degradation

thereafter) Slows down the whole network, not just characterization run

Product Support Virtually abandoned in the US Support and Development now in China No future development roadmap

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Magma CellRater CR – Strengths and Weaknesses

Strengths Strong Market Presence Full featured Works will with existing library Simple to use – GUI driven

Weaknesses Legal and financial problem with Magma/Synopsys lawsuit Not member of Synopsys In-Sync program so do not have access to

LC, DC, and PTSI to validate operation—must rely on customers Unable to handle complex cells Manual set-up Script based solution with no IP Requires external SPICE (integration with MSIM) Non-scalable technology

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AccuCell Strengths

Algorithmic approach Proven software for 8 Years While Developed, Sold and Supported by

Circuit Semantics Large Customer Base of DynaCell and AccuCell Functional recognition

Good for casual users re-characterizing foundry-supplied or commercial libraries

Automatic function extraction and verilog model generation with optimization Automatic vector generation - just plug and play

Supports Domino and self-timing logic – for microprocessor people SmartSpice accelerated simulator improves overall throughput Automated slope/load selection I/O PADS, different logic High accuracy Database driven

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AccuCell Strengths (cont’d)

SmartSpice license sold with each AccuCell license Attractive to new users with little available simulation resource Tight integration insures compatibility

Supports SmartSpice, HSPICE, Eldo, Spectre Supported on Solaris and Linux Independent of Magma for Synopsys Customers

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AccuCell Weaknesses

Synopsys customers– does not support for PrimeTime SI Noise modeling (CCS)

Cadence customers– does not support ECSM for Encounter, SignalStorm

Cadence customers - does not support CDB Limited state dependent power characterization Does not have oversampling/reduction but it is not important with

Auto Table Selection (ATS) No support for high speed LVDS I/Os – IORater Product No support for memories – MemRater or MemCut Products Less rigorous model verification

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Nangate Library Characterizer – Strengths and Weaknesses

Strengths Support of CCS and ECSM Support multi-processing through Sun Grid Engine and LSF GUI Wizard for characterization setup Datasheet generator supports both pdf and HTML Complements Library Creator product Library comparison utility and GUI

Weaknesses Small startup with only a dozen people Internal SPICE subset is minimal functionality Only available on Linux No VITAL/VHDL output No customers announced yet

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Altos Liberate – Strengths and Weaknesses

Strengths Support of CCS and ECSM Low power MCTOS examples Uses Virage as reference account Library comparison utility and GUI Foundry supported

Weaknesses Small startup with only a dozen people Internal SPICE subset is minimal functionality Only available on Linux No VITAL/VHDL output No customers announced yet

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AccuCell’s Advantages

Easy Setup Automated Function Extraction Automated Optimum Vector

Generation Supports Complex Custom Cells

I/O Pads Dynamic Logic Differential Logic Cells with large number of inputs

Automatic Slope/Load selection Higher accuracy Integrated SPICE for Blazing Speed Flexible usage

Measurements, API Scalable technology

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Accurate Cell Characterization saves Engineering Resources and prevents Expensive Silicon Re-spins!

Manual Function Identification


Convert Transactions to

Vectors

Run Simulation

Extract Results

Build Model

Automatic • Function Extraction • Vectors Generation • Integrated SPICE • Database • Build Model

Conventional Tools Script Based Flow

AccuCell Algorithmic Approach


Customers’ Use of AccuCell

Library Characterization Standard cell Custom cell and I/O Complex cell - Dynamic, dcvs

Migration of cells to new processes

Foundry to foundry Process to process PVT variations

QA of existing libraries “On-the-fly” characterization

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Well suited for High Performance Cell based design


Usage Model

Commercial Libraries Users Typical Library Size 300 to 500 Cells with 40 – 60 sequential

Avg. Run Time/Comb Cell = 10 min (AOI, MUXs, XOR, NAND, NOR INV) Avg. Run Time/Sequential Cell = 4 hrs (FFs and Latches) Total run time for 400 cells with 50 Seq = 350*.166 + 50*4 = 258 hrs = 11

days (w/ 1 copy) Number of Various corners (PVT) traditionally 3 (SS, FF, Typical)

Total run time for all corners = 11*3 = 33 days!! At 65 nm some companies run 27 corners = 11*27=300 days

Typically need 5 copies to complete in 1 week assuming integrated SmartSpice is being used. Run time may be 2 to 4 times more with external SPICE.

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Usage Model (cont’d)

Structured Custom Design Library size 600 – 900 cells Get designed over a period of several months # of Copies dictated by number of users, usually >4 Similar requirements as commercial lib users when migrating to

another process

Company A had 700 cells (20 Seq) took 48 hours with 10 AccuCells

5 pack with option of peak demand usage may be more aligned model to customers’ requirements

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Benefits of AccuCell (1 of 3)

Performance Improvement – Higher Premium, Design Wins Customer Cells along with Std Cells New logic styles – Dynamic & differential

Design Quality – Saves Silicon re-spins Automation – functions, vectors, measurements Verbose CSI Models

Better timing and coverage when used with AccuCore Accurate Results

Design Cycle reduction – Market Window, Design Wins Automation – frees up engineering resources

Several weeks of engineers from chasing phantom timing problems

High Productivity, automated cell characterization solution gets the design quicker to First Pass Silicon

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Productivity Improvement Week or less for set-up from scratch compared to weeks On time accurate libraries – shorter design cycle Complete library characterization at 3 PVT within a week with few or

same computer resource compared to over a month with other competing software

Fewer engineering resources due to automation and removal of overhead of maintaining internal tools

Higher Quality, Higher Yields, Quicker Time-to-Market Saves silicon re-spins Reduces engineering resources, enables faster design convergence

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Cost Significantly cheaper than outsourcing

Security IP Control Third-party dependence

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AccuCell vs. Competition

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Company Product Strength Weakness

Magma Cell Rater Strong Marketing, characterization GUI environment, completeness, multi-voltage I/Os, validation

No technology, manual setup, accuracy. Large and custom cells more of data pre and post processing

Synopsys MTB/Nanochar/Liberty NCX

Large Installed base. Connection to Synopsys tools that use .lib

Old unsupported tool. Very slow and requires extensive set-up.

Lib Tech Inc LibChar Library Completeness, Validation, I/Os, Pricing

No technology, manual setup, accuracy. Large and custom cells more of data pre and post processing. Support-very limited. No distribution channel.

Altos Liberate Variety, fast, statistical, foundry support New, track-record, unproven

Nangate Library Characterizer

CCS/ECSM, SUN GRID/LSF GUI Wizard, datasheets, lib compare

Startup, SPICE subset only, no VITAL/VHDL

Design Houses Home Grown Customized to the need, unlimited licenses Usually lacks automation in the area of vectors and function extraction. Out-dated. Poor maintenance and support.

Simucad AccuCell Automation, accuracy, Flexibility, scalability, throughput, technology, built-in SPICE allows customization thru API

I/F (GUI), library validation, and differential I/Os, memory char, CCS, ECSM


High Productivity, Automated Cell Characterization Solution

Easy Setup Function Extraction Vector Generation

Aggressive Design Styles Outputs

Liberty .lib (for Synthesis, Static Timing, & Power

Structural Verilog Validation setup Datasheet

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Easy to Setup Reduces Design Cycle

Improves Design Quality

AccuCell Boolean

Extraction

Vector Generation

SmartSpice Simulations

Delay Database

Config File

SPICE Models

SPICE Netlist

Liberty .lib Verilog .tbench Datasheet

AccuCell Sales Training 27

Conventional Cell Characterization

Typically a set of poorly documented scripts where at best one person really knows how they work

Manual function identification is time consuming because original cell designer must be consulted

All timing arcs must be identified and converted into test vectors to achieve the desired transitions to measure

Many measurements must be made and stored

Models must be built that are syntactically correct

Conventional Approach

Manual Function Identification


Convert Transactions to Vectors

Run Simulation

Extract Results

Build Model

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