طراحي و تحلیل مبدل آنالوگ به ديجيتال کم‌توان با استفاده از ترانزيستور نانولوله کربني
محورهای موضوعی : مهندسی برق و کامپیوترسعیده حیدری 1 , داریوش دیدبان 2 *
1 - دانشگاه کاشان
2 - دانشگاه کاشان
کلید واژه: مبدل آنالوگ به ديجيتال, مبدل فلش, مقايسه کننده TIQ, توان مصرفی پایین, انکدر ROM, انکدر Fat tree .,
چکیده مقاله :
امروزه مبدل‌هاي آنالوگ به ديجيتال به عنوان جزء جدايي‌ناپذير از سيستمهاي بر روي تراشه به شمار مي‌آيند زيرا فاصله بين دنياي فيزيکي آنالوگ و دنياي منطقي ديجيتال را از بين مي‌برند. اين امر و تمايل روزافزون به استفاده از تجهيزات قابل حمل، سبب شده ملزومات طراحي اين مبدل‌ها مانند سرعت، توان مصرفي و سطح اشغالي بهبود يابند. راهکارها و روش‌هاي مختلفي جهت بهبود عملکرد مبدل‌ها ارائه شده که روز به روز در حال پيشرفت مي‌باشند. با توجه به اهميت روزافزون مبدل‌ها، در اين مقاله يک ADC سريع و کم‌توان با استفاده از CNTFET طراحي شده و عملکرد آن با نمونه مشابه MOSFET با همان طول کانال مورد بررسي قرار گرفته و همچنين عملکرد مبدل طراحي‌شده با دو نوع کدگذار مختلف، ROM و Fat tree مورد مطالعه قرار گرفته است. در ادامه، نتايج شبيه‌سازي که با بهره‌گيري از نرم‌افزار HSPICE در تغذیه 9/0 ولت به دست آمده ارائه گرديده است. نتايج شبيه‌سازي مبدل در فناوری CNTFET بهبود قابل توجهي در پارامترهاي توان و تأخير نسبت به طراحي مشابه در فناوری CMOS نشان مي‌دهد. توان مصرفي و تأخير مبدل مبتنی بر نانولوله کربنی با کدگذار نوع ROM به ترتيب 5/92% و 54% و با کدگذار Fat tree به ترتيب 93% و 72% نسبت به مبدل‌های مبتنی بر ترانزیستورهای CMOS بهبود يافته‌اند.
Nowadays, analog to digital (A/D) converters are indistinguishable parts of system on chip (soC) structures because they omit the distance between analog real data and digital logic world. Due to this fact and ever increasing trend for using portable instruments, the figures of merit for design of these converters such as speed, power and occupied area are improved. Different methods are proposed to improve the performance of these converters. In this paper, we design a fast and low power ADC using carbon nano-tube field effect transistor (CNTFET) and then its performance is comprehensively compared with a MOSFET based counterpart at the same technology node. The performance is studied two encoders: ROM and Fat tree. The obtained results are presented using HSPICE simulator at 0.9 V power supply. The simulated data from CNTFET based converter shows significant improvements in delay and power compared with its CMOS based counterpart. The power and delay obtained from CNTFET based converter using ROM encoder are improved by 92.5% and 54% with respect to the same parameters obtained from CMOS based design while the improvements using a Fat tree encoder in CNTFET converter reaches 93% and 72% in comparison with CMOS conventional design.
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