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STA : Quality of constraints validation at Block and Fullchip level

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 In the semiconductor industry, meeting stringent timing requirements is of paramount importance for successful design implementation. Static Timing Analysis (STA) is a vital technique used to verify and validate design constraints, ensuring proper functionality and optimal performance. Validating the quality of constraints is essential, as they decide design quality, performance, and faster time-to-market. With designs growing larger and intricate, extending parallel STA analysis is necessary at both the Block level as well FullChip level, accounting for inter-block interactions and global timing considerations. This article explores the challenges and best practices of validating constraints at both levels, highlighting common issues and proposing potential solutions. By addressing these aspects, the primary aim is to streamline the design process and create robust, high-performance digital designs. Importance of Design Constraints For any ASIC chip, design constraints are crucia...
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Low Power Design: A Key to Efficient ASICs

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Consider below scenario: If you have designed one smartphone very faster and less area. speed is very high (no lag) also response is quicker. but what if the device getting discharged within 30min ?  will you buy that smartphone ..? I am assuming your answer would be a big "NO" (unless you have figured out way to reduce battery usage...!! ) Well, there are multiple such scenarios possible if you start counting... that's why requirement of "Low Power" comes into picture. Low Power : significance  for advanced technology mode designs, as frequency is very high which leads to high switching which consumes more dynamic power (internal + switching power).  Also as devices shrinks, Leakage is more compared to older node which leads to Leakage (or standby) power. Thus in lower nodes, along with smaller area and higher speed, it is really important to Low power. Categories of Low power design Multi-voltage design [ Power domain operates at different voltage] If there ar...
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Challenge 14 : Advanced STA

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 Hi All, Challenge on Advanced STA. Please check below image and share views if any issues w.r.t STA: Add you views in comment. Let me know if any further information is required.
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PowerPlan : basic introduction

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 Hi All, Hope you have gone through posts related to Flooroplan and Synthesis. Lets understand importance of PowerPlan in ASIC design flow. PowerPlan In older Technology nodes, main priorities were given to Timing and Area because these parameters  were dominant over power . however in lower nodes, as devices are shrinking there are more numbers of devices in same area. Also to supply power to these smaller devices, Power supply also becoming smaller over a time ( consider mobile batteries. its size keep reducing in last 10 years..!!! and also supply power is also reduced i.e. in older nodes, supply voltage in range of 1.5-2 V while it is drastically reducing now a days within 0.6-0.8 range).  in lower nodes, to address complex timing challenges power consumption is increasing   hence in  power is more dominant over area and timing.  Terminologies Power PAD : it is source from where chip get the power from external world. for wire-bounding Technology,...
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Challenge 13 : Area optimization

****** Area Optimization ****** Suppose you have been given one design and respective Technology  related files and been asked to Optimize area as much as possible considering reasonable Routing DRC numbers and reasonable Hold/Setup violations   (Only Internal). Data Provided: - RTL  - Technology related data You are allowed to modify below: - Constraints :  Constraints file is not given. you can use any constraints requires (but dont make all paths as False paths 🙂 ...!!!) - Floorplan shape and size : any shape and size can be used - Port Placement : no port placement is given. you can place ports in any layers, any location (no ports should be unplaced..!) - any Synthesis/PnR implementation Tool can be used. Goal: - Overall area (stdcell/Physical cells) should be as minimum as possible - Internal Setup/Hold timing should be less than uncertainty - Routing DRC should be reasonable  There are many ways possible here. Please share your approach here.  ...
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Challenge 12 : ECO implementation

  **** ASIC Physical Design ECO Challenge**** Assume below scenario: Design is clean w.r.t Timing Qor/Physical Verification/EMIR. -- Base layer is Frozen. [ good for Tapout ] Timing is Clean Signoff Physical Verification is Clean EMIR is Clean Formality is PASS Due to some Functional ECO, design is opened again and new timing violations were observed. Attempted Timing violations through metal-layers optimization only. after optimization, Timing is Clean Signoff DRC is Clean Signoff ERC/LVS is clean EMIR is Clean Formality is PASS Base layer XoR is clean w.r.t before ECO Is this good to Tapout this design ? Share your answer as "Yes" or "No" in comment box. I will share my views later as first would like to give opportunities to all members to share their views.
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Static Timing Analysis (STA): The Nervous System of Design

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 Static Timing Analysis (STA) in chip design can be  correlated with the nervous system of the human body. Below are few analogies : Signal Propagation In STA, Signal propagation from one sequential element to other element is analyzed and it is make sure that it meet requirement such as Setup/Hold slack. Similarly, Nervous systems ensures that nerves signals propagate properly between brain, spinal cord and other body part. Critical paths in STA, it is really important to identify and critical paths same ways, in body it is important to analyze critical paths such as spinal cord and  Constraints In STA, Constraints plays import role for critical paths. The nervous system also has constraints, such as reaction times, which must be within limits for the body to respond effectively. Optimization: STA helps optimize the design to minimize timing violations by following constraints. The nervous system adapts and optimizes signal transmission, for example, by strengthening neu...
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Challenge 11 : Setup/Hold slack calculation

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Challenge on Setup/hold slack calculation... check below image. without crosstalk impact, setup/hold slack between FF1-->FF2 is 0ps.  with crosstalk, crosstalk of 10ps is introduced on below 3 nets.  what will be setup/hold slack considering this crosstalk effect?  #STA #Setup #Hold  #Challenge Type your answer in Comment below.
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Multi Mode Multi Corner (MMMC)

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MMMC (Multi-Mode Multi-Corner ) is needed in modern chip design to make sure that chip works properly in all conditions. It handles changes in manufacturing, power, temperature, and how the chip operates in different modes. Before understanding details about MMMC, Lets try to understand its importance through below analogy. Suppose you are making a chip which will be used in mobile. in order to have more sells all over India, it is really important that same mobile handset should work in all states including Jammu and Kashmir (J&K) , Gujarat and Kerala (Of course it will be restricted in Military area...!!). J&K is very cold area where temperature might be as low as -40 Degree while Rajasthan's Thar Desert where temperate might go as high as 40 Degree.  other states where  average temperate is in range of 20-30 Degree. In order to have sells across India, it is really important that Mobile Handset should work properly with expected performance in all states.  Thus...
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