The World Leader in High Performance Signal Processing Solutions
Farnell & Analog Devices
partner to host a webinar on‘Converter Simulation –
Beyond the Evaluation Board’
Analog Devices’ Approach to Behavioral ModelingBy: Tom MacLeod
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Outline
Modeling OverviewWho am I?What is Converter Simulation?Why Model at All?How Does One Model Behavior?How Does One Model Converter Behavior?Modeling Converter BehaviorCan behavioral modeling be any good?What can converter modeling do for me?Does Analog Devices currently have a converter modeling tool?What is the Future for Behavioral Modeling?
ReviewQ&A
Who am I?
My name is Tom MacLeodApplications/Software Engineer for the Converter System
Applications groupDeveloper of ADIsimADC™Developer of Tools/Scripts for the labTraditional Applications for High Speed ADCs
Been with ADI for 7.578 yearsGraduated from North Carolina State University
What is Converter Simulation?
It is a “top down” or “black box” approach to modeling a converter (inherently a mixed signal device)
It models the “what” as opposed to the “how”Models the transfer function rather than multi-stage pipeline Models harmonic distortion rather than transistor imbalance
within a current mirror of an input buffer
It implements a unique strategy, modeling characteristics of interest (proxies) without needing to know the circuit level implementation
What is Converter Simulation? (cont.)
The concept of modeling converter proxies generalizes to a modeling philosophy known as “behavioral modeling”
Behavioral Modeling – the ability to model apparent behavior of a process or entity without simulating the complex internal subsystems which yield such behavior
Example: IBIS (Input Output Buffer Information Specification ) Models IBIS is a method of providing information about the input/output buffers of an
integrated circuit to the outside world. It is an EIA (Electronic Industries Alliance) standard. The idea of IBIS is to provide the behavioral aspects of a circuit without providing the actual circuit information to the user. – Wikipedia
Models: Current vs. Voltage Voltage vs. Time
What is Converter Simulation? (cont.)
What behavioral modeling is notNot SPICE (Simulation Program with Integrated Circuit Emphasis)
General-purpose analog electric circuit simulator
Not a database
Not Evaluation Software
Why Model at All?
Simulation is becoming heavily used in system design and initial characterization to reduce risk and cost
Modeling communicates information about new products more quickly and comprehensively than traditional means of product introduction
Modeling communicates information about our current portfolio more efficiently and intuitively to the “young kids with their iPods and videogames”
Why Model at All? (cont.)
Benefits of Behavioral ModelingReduces the technical complexity of the modeling tool
Decreases simulation timeIncreases productivity and user satisfaction
Abstracts implementation and consequently intellectual property
Leverages reuse of modeling tool for similar productsCan parameterize proxies thus providing a framework to support
similar products
Simplifies model creation processImportant when creating and maintaining hundreds of products
How Does One Model Behavior?
Answer: Math Models!
Example – Gaussian Distribution
Example – Population Growth
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Modeling Converter Behavior
A model should faithfully reproduce converter proxies (both static and dynamic) such as:OffsetGainQuantizationSample Rate DependenciesInput BandwidthJitter SensitivityLatencyAC and DC Linearity
Modeling Converter Behavior (cont.)
It should be flexible enough to support different architecturesPipelineDelta-SigmaSAR
Support many “bolt-on” featuresNumerically Controlled OscillatorsDigital FiltersNoise ShapersAnalog FiltersLow Noise AmplifiersVariable Gain Amplifiers
Modeling Converter Behavior (cont.)
A model should be contained within a library so that it can be called from multiple applicationsDynamic Linked Library (DLL)
Can behavioral modeling be any good?
Model
Physical
Part = AD6645
Model
Can behavioral modeling be any good? (cont.)
AD9271(Octal LNA/VGA/AAF/ADC)
Model
Physical
What can converter modeling do for me?
Live datasheetFind typical performance not explicitly listed on the static
datasheet
Part = AD9229, Ain = 49.3 MHzSNR = 68 dB, 2nd = -82.8, 3rd = -80.3
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What can converter modeling do for me? (cont.)
DidacticConsider impact on performance from jitter (AN-501)
AD9246, Ain = 2.3 MHz, fs = 125 MSPS
Calculate “composite DNL”
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What can converter modeling do for me? (cont.)
AD9246, Ain = 201.3 MHz, fs = 125 MSPS
13 fsec difference
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What can converter modeling do for me? (cont.)
DidacticConsider effects of adding band limited dither
Without Dither With Dither
What can converter modeling do for me? (cont.)
Product selectionFind the product that meets your requirements under your
conditionsWelcome to the online ADIsimADC Design Tool
http://www.analog.com/adisimadc
Click here
What can converter modeling do for me? (cont.)
Input yourrequirements(SNR > 78 dB
SFDR <= -85 dBc)
Click here
Input yourconditions
What can converter modeling do for me? (cont.)
Models that metmy requirements
What can converter modeling do for me? (cont.)
It worked!SNR = 78 dB
SFDR = -93 dBc
What’s 100kvolume pricing?
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What can converter modeling do for me? (cont.)
Product EvaluationA subset of products (those ending in .PMF) support a register
map interface
Example – AD6657
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What can converter modeling do for me? (cont.)
Tuning word changed from 28 to 0Same as real device
What can converter modeling do for me? (cont.)
System Level SimulationSimulate the effects a particular ADC will have on your system
LTE Uplink (5 MHz) waveformAD6655 (14-bit IF receiver)
SNR = 65.7 dB
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Does Analog Devices currently have a converter modeling tool?
Yes - ADIsimADC
Where can I buy ADIsimADC?
You can’t buy it! It’s free!Visit: http://www.analog.com/adisimadc
As part of ADI’s “whole product initiative” There is no cost to use this tool; use it in whatever environment
you prefer
+ =
Where can I buy ADIsimADC? (cont.)
We package it with VisualAnalog (also free)
Just install VisualAnalog, run it,browse for your favorite ADC,select it and start modeling!
Also available as an online design tool
What products are currently supported?
AD6645_105 AD9214_105_1V AD9218_80_1V AD9230_210 AD9238_20 AD9246_105 AD9255_125 AD9268_80AD9445_105_3p2V AD9600 AD9629_40 AD80141 AD9230 AD9252 AD9287 AD9609
AD6645_80 AD9214_65_2V AD9219_40 AD9230_250 AD9238_40 AD9246_125 AD9255_80 AD9271 AD9445_125_2V AD9601 AD9629_65 AD9204 AD9231 AD9254 AD9289 AD9626
AD6655 AD9214_80_1V AD9219_65 AD9231_20 AD9238_65 AD9248_20 AD9258_105 AD9272AD9445_125_3p2V AD9609_20 AD9629_80 AD9211 AD9233 AD9255 AD9430 AD9627-11
AD6657 AD9215_105 AD9222_40 AD9231_40 AD9239_170 AD9248_40 AD9258_125 AD9273 AD9446_100_2V AD9609_40 AD9640 AD9214 AD9236 AD9258 AD9433 AD9627
AD80141 AD9215_65 AD9222_50 AD9231_65 AD9239_210 AD9248_65 AD9258_80 AD9287AD9446_100_3p2V AD9609_65 AD9644_80 AD9215 AD9237 AD9259 AD9444 AD9629
AD9204_20 AD9215_80 AD9222_65 AD9231_80 AD9239_250 AD9251_20 AD9259 AD9289 AD9446_80_2V AD9609_80 AD9649_20 AD9216 AD9238 AD9262 AD9445 AD9640
AD9204_40 AD9216_105 AD9226_2V AD9233_105 AD9244_40 AD9251_40 AD9262 AD9430_170_LVDS AD9446_80_3p2V AD9626_170 AD9649_40 AD9218 AD9239 AD9265 AD9446 AD9644
AD9204_65 AD9216_65 AD9228_40 AD9233_125 AD9244_65 AD9251_65 AD9265_105 AD9430_210_LVDSAD9460_105_3p4V AD9626_210 AD9649_65 AD9219 AD9244 AD9268 AD9460 AD9649
AD9204_80 AD9216_80 AD9228_65 AD9236 AD9245_20 AD9251_80 AD9265_125 AD9433_105 AD9460_80_3p4V AD9626_250 AD9649_80 AD9222 AD9245 AD9269 AD9461
AD9211_200 AD9218_105_1V AD9229_50 AD9237_20 AD9245_40 AD9252 AD9265_80 AD9433_125AD9461_125_3p4V AD9627-11 AD6645 AD9226 AD9246 AD9271 AD9480
AD9211_250 AD9218_40_1V AD9229_65 AD9237_40 AD9245_65 AD9254 AD9268_105 AD9444AD9461_130_3p4V AD9627 AD6655 AD9228 AD9248 AD9272 AD9600
AD9211_300 AD9218_65_2V AD9230_170 AD9237_65 AD9245_80 AD9255_105 AD9268_125 AD9445_105_2V AD9480 AD9629_20 AD6657 AD9229 AD9251 AD9273 AD9601
All high speed (>20 MSPS) ADCs for the last 5 years. 188 models so far…
What is the Future for ADIsimADC?
Support for high-precision ADCs <20 MSPS16-bit to 24-bit delta sigmas and PULSARsDepends on proxies we identify are important
Support for more accurate modelsBetter integration with SPI control softwareUser defined phase noise profilesArbitrarily oversampled inputsStatistical distribution of products (Monte Carlo)Temperature sensitivitiesOpen to suggestions!
What is the Future of Behavioral Modeling?
Support for precision ADCs
Support for DACs
Support for clocks
Support for amplifiers
Support for modulators/demodulators
Need feedback!
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Review
Behavioral modeling has been shown to be a viable and effective technologyPurposes
Live datasheet Didactic Product selection Product evaluation System level simulation
Analog Devices freely offers ADIsimADC, a converter behavioral modeling tool as part of its “whole product” initiativeWe want this tool to be part of a dialog between you and us
Give us feedback Provide suggestions Try and break it
Analog Devices is committed to maturing this technology
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Outline
Modeling OverviewWho am I?What is Converter Simulation?Why Model at All?How Does One Model Behavior?How Does One Model Converter Behavior?Modeling Converter BehaviorCan behavioral modeling be any good?What can converter modeling do for me?Does Analog Devices currently have a converter modeling tool?What is the Future for Behavioral Modeling?
ReviewQ&A
The World Leader in High Performance Signal Processing Solutions
Thank You!
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