Spreadsheet style allow you to sort, manipulate your design netlist to easy managing both electrical and physical constraints
SPECCTRAQuest Power Integrity module is a new add on option to SPECCTRAQuest SI Expert. It embeds proven technology from Sun Microsystems, Inc along with design and analysis environment from Cadence to address power delivery issues in high-speed PCB systems design. SPECCTRAQuest Power Integrity embodies a methodology used to design and optimize frequency dependent characteristics of power delivery systems in high speed systems design. It offers an integrated design and analysis environment to allow users many quick iterations of “change-simulate-analyze” in a short period of time.
Over the past decade, power delivery requirements for modern high-speed systems have been increasing rapidly even as the supply voltages have been dropping from 5V in early 1990s to less than 2V in systems being designed today. Chart above shows how the current requirements have grown 5 times faster than the voltages have dropped on most high-speed systems with microprocessors and complex bus architectures. This has resulted in complex high-speed microprocessor based designs requiring over 100 watts of power to be delivered to it. As the supply voltage has dropped in these systems, the tolerance ripple voltage has shrunk as well. 5% allowed ripple in a 5V system meant that the supply voltage could tolerate a swing of 0.25V. The same 5% ripple in a 1.8V system means the swing cannot be more than 0.09V! The systems are becoming more sensitive as the supply voltage drops. The need to reduce the supply voltage will continue to be driven by the battery life and thermal concerns. Most high-speed systems that have front end or post layout SI/Crosstalk simulations performed assume a clean dependable supply voltage. The approach was to sprinke more capacitors than needed to avoid hot spots. Any that were missed were caught in a prototype debug stage. This approach drives up the system per unit cost and complexity (harder to place and route when real-esate is tight).
Power Delivery System design errors show up in various places. Unreliable power delivery (supply droop) can cause timing failures, which can result in system crashes. Improperly addressed hot spots in a high-speed system can increase common mode EMI preventing the product from shipping. Not solving the problem or addressing it too late in the cycle increases development costs and causes the product to miss its time to market window of opportunity, which can be fatal for many products in a competitive market place.
How do people deal with these issues today? Most people tend to deal with it either by over-designing (a bypass cap per power supply pin per device) or by adding an iteration after the prototype debug shows problems. Both approaches are becoming unacceptable if the system cost or real-estate is an issue. Certainly adding an iteration to build a prototype eats into the precious time to market window for most companies building complex high-speed PCB systems. Some companies that use simulation for power delivery system design use standalone time domain (TD) simulation engines to find the voltage swing. The problem is that the cause of the swing is not identified by the TD simulation. Leaving the user to guess at the cause, make a fix and then run simulation again to see if the problem is solved or not. This is the “shooting in the dark” approach. There is no gurantee of convergence. There is a better approach……….
The approach that Cadence has taken is a better approach. It investigates the problem in the frequency domain to identify the cause and also to suggest a solution that can fix the problem. The approach is rooted in the fact that power delivery system’s impedance is freuency dependent and must be controlled for all frequency ranges from DC to daylight. In addition to simulating in frequency domain to identify the problem and suggest a solution, SPECCTRAQuest Power Integrity offers an environment that makes multiple iterations of “change-simulate-analyze” very quick and easy. It offers an intergated design and analysis environment allowing the users to focus on the problem instead of struggling with data translation issues between the CAD system and the analysis engines.
High Speed PCB Design and Analysis
®Agenda• Today’s High Speed PCB design challenges• Cadence PCB solution overview• Demonstration overview• Summary• Q&A2 CADENCE DESIGN SYSTEMS, INC.
®MARKET CONVERGENCEIS DRIVING DESIGN CONVERGENCE MARKET CONVERGENCE DESIGN CONVERGENCE Communications Hardware Software Computing Multimedia Digital Analog IC Board Consumer3 CADENCE DESIGN SYSTEMS, INC.
® High Speed Design Challenges IC Board 1 • System timingClock 4Driver Setup Hold 2 Tco D0 3 Flight Time D0 – What is the maximum data rate for reliable data transfer? • Waveform integrity D1 D1 D2 D2 Driving Receiving D0 D1 D2 – Do signals meet applicable electrical requirements? • Crosstalk – Do the signals interfere with each other? • Power and/or ground plane stability – Are power voltages at the ICs sufficiently controlled? • EMI (differential and common mode) – Are critical signals radiating too much energy? – Are power planes producing common-mode radiation? 4 CADENCE DESIGN SYSTEMS, INC.
®PCB System Design Flow and Products Communications Functional Functional NC Sim Verification Verification PSpice/AWB Computing SPECCTRAQuest C Multimedia Exploration PCB Design Infrastructure O C Design Entry S Capture CIS N O I Concept HDL S N T Floorplanning R S A A SPECCTRAQuest T N I Consumer R A N A High-Speed L Allegro T I PCB Layout Y SPECCTRA M IC Board N S A Digital Analog T I SPECCTRAQuest N S S A IC G E Packaging Advanced Package R Designer5 CADENCE DESIGN SYSTEMS, INC.
® IC BoardPCB System Design Flow and Products Communications Functional Functional NC Sim Verification Verification PSpice/AWB Computing SPECCTRAQuest C Multimedia Exploration PCB Design Infrastructure O C Design Entry S Capture CIS N O I Concept HDL S N T Floorplanning R S A A SPECCTRAQuest T N I Consumer R A N A High-Speed L Allegro T I PCB Layout Y SPECCTRA M IC Board N S A Digital Analog T I SPECCTRAQuest N S S A IC G E Packaging Advanced Package R Designer6 CADENCE DESIGN SYSTEMS, INC.
®SPECCTRAQuest products today PCB Systems IC-Packaging Model Management EnvironmentPower Integrity (PI) SPECCTRAQuest Power Integrity SPECCTRAQuest SPECCTRAQuest SI Expert IC Packaging (SQIC)Signal Integrity (SI) SPECCTRAQuest Signal Explorer An environment for creation, verification and management of all types of models7 CADENCE DESIGN SYSTEMS, INC.
® IC BoardIntroducing the Design Flow• High speed design issues must be managed throughout the PCB design process Model Pre-Route Post Route Simulation Development Sol’n-Space Analysis & Verification Analysis Verification Topology Constraint Layout Entry & Driven Floorplanning Layout8 CADENCE DESIGN SYSTEMS, INC.
® IC Board SPECCTRAQuest in the PCB Design flow Physical Layout Physical Layout Exploration Exploration Design/Implementation Design/Implementation FP FP Place Place Route Route Simulation Simulation Verification Verification Design Specs SQ-SigXP SQ-SigXP Concept HDL Expert Concept HDL Expert SQ SQ Allegro Expert Allegro Expert CM CM CM CM CM CM CM CM I/O models SPECCTRAQuest SPECCTRAQuest CM CM • Model Verification SPECCTRA • Topology explorations • Rules development • Timing driven floorplanning • Post placement verification9 • Post route verification CADENCE DESIGN SYSTEMS, INC.
® Constraint Driven Layout • Design rule violations during interactive routing are identified in real-time • Autorouter follows design rules - powerful integration with SPECCTRA! • Because solution space analysis has defined a set of conditions under which the nets are known to work, chance of first-pass success is high. – Nets can be ripped up and rerouted, as long as they still adhere to the design rules10 CADENCE DESIGN SYSTEMS, INC.
® PSD 14.0 Constraint Manager • Common, powerful environment for constraint entry / editing / management and verification • Single mechanism for managing constraints throughout the design process11 CADENCE DESIGN SYSTEMS, INC.
®Constraint Manager – Key Features • Spreadsheet-based graphical interface – No cryptic formats or cumbersome updating • Provides unsurpassed Integration across the entire design flow – Consistent Front to Back solution – No translations with static constraint data – Directly integrated with schematic and PCB databases – Analysis engines can update spreadsheet data interactively12 CADENCE DESIGN SYSTEMS, INC.
®SPECCTRAQuest Power Integrity • Innovative technology developed and proven by Sun Microsystems, now commercialized by Cadence Design Systems, Inc. to address Power Delivery issues in high-speed PCB System Designs. • A design tool / methodology used to design and optimize the frequency-dependent characteristics of Power Delivery Systems in high-speed system designs • An integrated solution to allow many quick iterations of “change-simulate-analyze” • Introduced in PSD 14.1 release CADENCE DESIGN SYSTEMS, INC.
® Power Delivery Requirements Trend Year Voltage Power Current Frequency Ztarget (Volts) (Watts) (Amps) (MHz) (m-Ohms) 1990 5 5 1 16 250 1993 3.3 10 3 66 54 1996 2.5 30 12 200 10 1999 1.8 90 50 600 1.8 2002 1.2 180 150 1200 0.4• Power dissipation and longer battery life fueling decreasing chip power supply voltages – Maximum allowable supply ripple decreases accordingly• SoC, SiP fueling trend towards devices with large number of devices – The instantaneous switching current required is enormous• The maximum acceptable power supply ripple voltage determines the target impedance which must be maintained across the PCB CADENCE DESIGN SYSTEMS, INC.
®Power Delivery System Design Challenges • Power supply droop – Alters system timing and can cause Setup failures – Can cause sampling errors that results in a system crash • Unreliable power delivery system design can cause increased common-mode EMI preventing product shipment due to compliance problems • Power delivery system impedance is frequency-dependent – Must be controlled for all frequency range of all transient currents Increases Development Costs and Increases Development Costs and Time to Market is LOST! Time to Market is LOST!15 CADENCE DESIGN SYSTEMS, INC.
® Power Delivery System Design - How it is done today • Standalone analysis tools – Design data translation is left up to the user – Changes to the design resulting from simulation is manual • Use Time Domain simulation – Power delivery system impedance is frequency-dependent! – With only time domain simulation, it is like searching for needle in a haystack • Over design - add more de-coupling capacitors than necessary – Expensive solution that may not work16 CADENCE DESIGN SYSTEMS, INC.
®The Cadence approach • Allow users to determine the needs of the power delivery system – Target impedance – Decoupling capacitor requirements • Provide frequency domain analysis to find problem areas • Provide an integrated PCB design editor to optimize capacitor placement Develop reliable power delivery system Develop reliable power delivery system while shortening design cycle time while shortening design cycle time17 CADENCE DESIGN SYSTEMS, INC.
Introducing … ®SPECCTRAQuest Model Integrity(in v14.2) PCB Systems IC-PackagingPower Integrity (PI) SPECCTRAQuest Power Integrity SPECCTRAQuest SPECCTRAQuest SI Expert IC Packaging (SQIC)Signal Integrity (SI) SPECCTRAQuest Signal ExplorerModel Integrity (MI) SPECCTRAQuest (in v14.2) Model Integrity for An environment creation, verification and management of all types of models18 CADENCE DESIGN SYSTEMS, INC.
®SQ Model Integrity• Family of products that offers model creation, manipulation and verification environment – First release (PSD release 14.2) will offer the basic creation/editing and sanity check environment for IO buffer models for following formats – Cadence (DML) – Quad [translator only] – IBIS 3.2 [.ibs, .pkg, .ebd files] – Future releases will offer advanced options that will provide verification environment and handle different kinds of models – Capacitor models for use with SPECCTRAQuest Power Integrity – S-Parameters – IC Package models – Connector/FPGA models – Link with PCB Librarian Expert series19 CADENCE DESIGN SYSTEMS, INC.
®SPECCTRAQuest Model Integrity20 CADENCE DESIGN SYSTEMS, INC.
®Demonstration Overview • Model development and validation using SPECCTRAQuest Model Integrity • Constraint Development using SPECCTRAQuest SigXP • Topology development using SPECCTRAQuest Floorplanner • Constraints verification throughout the process • System level verification using Design Link capability • Power Integrity21 CADENCE DESIGN SYSTEMS, INC.
®Brief Description - SPECCTRAQuest 14.2• SQ/Allegro, SQIC/APD UI Synchronization Allow users to switch between SQ & Allegro and SQIC & APD plus following commands to be changed in SQ – Display > Element to replace Info > Item – Logic > Net Schedule to replace Topology > Edit Pin Order – Place > Manually to replace Floorplan > Component Place23 CADENCE DESIGN SYSTEMS, INC.
®Brief Description –SPECCTRAQuest SI Expert 14.2• Custom measurements Custom measurements and Custom Stimulus will be available when simulating from the board level through the CM. In prior releases they were only available from SigXP• Differential Signalling improvements Extraction and simulation of coupled differential pairs in SQ, SigXP24 CADENCE DESIGN SYSTEMS, INC.
®Brief Description - Constraint Manager 14.2• Concept Database Synchronization Synchronizes constraints stored as Schematic properties and CM worksheets• Custom Measurement Provides SigXP’s custom measurement capability in CM. Ability to store custom measurements and to display measurement results in CM [requires SQ SI Expert]• Cross Probing Improvements Cross probing with Allegro to handle segments/ratsnest, pin pairs, DRCs and Clines25 CADENCE DESIGN SYSTEMS, INC.