ﺗﮑﻨﯿﮏ ﺗﺮاﻧﺰﯾﺴﺘﻮرﻫﺎي MOS ﺗﻮزﯾﻊ ﺷﺪه ﺑﺎ ﻗﺎﺑﻠﯿﺖ ﺗﺴﻬﯿﻞ ﭘﯿﺎده ﺳﺎزي ﺗﻄﺒﯿﻖ ﭘﻮﯾﺎي ﻋﻨﺎﺻﺮ در ﻣﺒﺪل دﯾﺠﯿﺘﺎل ﺑﻪ آﻧﺎﻟﻮگ ﺑﺎﯾﻨﺮي 10 ﺑﯿﺘﯽ

Distributed MOS Transistor Technique to Facilitate Dynamic Element Matching Implementation Capability in Low Power 10–Bit Binary Digital to Analog Converter

ﭼﮑﯿﺪه: ﻋﻤﻠﮑﺮد ﻣﺒﺪل ﻫﺎي دﯾﺠﯿﺘﺎل ﺑﻪ آﻧﺎﻟﻮگ ﻫﺪاﯾﺖ ﺟﺮﯾﺎﻧﯽ، ﺑﺨﺎﻃﺮ ﻋﺪم اﻧﻄﺒﺎق ﻃﻮل و ﻋﺮض ﺗﺮاﻧﺰﯾﺴـﺘﻮرﻫﺎ و اﺧـﺘﻼف وﻟﺘـﺎژ آﺳﺘﺎﻧﻪ و وﻟﺘﺎژ ارﻟﯽ آﻧﻬﺎ ﮐﻪ ﻧﺎﺷﯽ از ﺧﻄﺎي ﭘﺮوﺳﻪ ﺳﺎﺧﺖ اﺳﺖ، ﻣﺤﺪود ﻣﯽ ﮔﺮدد. ﻫﺮ ﭼﻨﺪ روش ﻫﺎي ﻣﺨﺘﻠﻔﯽ ﺑﺮاي ﺗﻌـﺪ ﯾﻞ ﺧﻄﺎﻫـﺎ ي ﻧﺎﺷﯽ از ﻋﺪم اﻧﻄﺒﺎق اﻟﻤﺎﻧﻬﺎ وﺟﻮد دارد، اﻣﺎ اﯾﻦ ﺧﻄﺎ ﺑﻪ ﻃﻮر ﮐﺎﻣﻞ ﻗﺎﺑﻞ ﺣﺬف ﻧﯿﺴﺖ. در اﯾﻦ ﻣﻘﺎﻟـﻪ ﺗﮑﻨﯿـﮏ ﺗﺮاﻧﺰ ﯾﺴـﺘﻮرﻫﺎ ي MOS ﺗﻮزﯾﻊ ﺷﺪه ﺑﺎ ﻗﺎﺑﻠﯿﺖ ﺗﺴﻬﯿﻞ ﭘﯿﺎده ﺳﺎزي ﺗﻄﺒﯿﻖ ﭘﻮﯾﺎي ﻋﻨﺎﺻﺮ در ﻣﺒﺪل دﯾﺠﯿﺘﺎل ﺑﻪ آﻧﺎﻟﻮگ ﺑﺎﯾﻨﺮي اراﺋﻪ ﺷﺪه اﺳﺖ ﺑﻪ ﻧﺤﻮي ﮐﻪ ﺑﺪون ﻧﯿﺎز ﺑﻪ ﺗﻮان ﻣﺼﺮﻓﯽ ﺑﺎﻻ و ﭘﯿﭽﯿﺪﮔﯽ ﻣﺪاري زﯾﺎد اﻣﮑﺎن ﮐﺎﻫﺶ ﺧﻄﺎي ﻧﺎﺷﯽ از ﻋﺪم اﻧﻄﺒﺎق ﺗﺮاﻧﺰﯾﺴﺘﻮرﻫﺎ و ﻧﯿﺰ ﺧﻄﺎي ﻧﺎﺷﯽ از ﺗﻐﯿﯿﺮات وﻟﺘﺎژ ﺑﺎر را ﻓﺮاﻫﻢ آورده اﺳﺖ. اﯾﻦ ﺗﮑﻨﯿﮏ ﺑﺮ ﻣﺒﻨﺎي اﻧﺘﺨﺎب ﺗﺼﺎدﻓﯽ از ﻣﯿﺎن ﺗﻌﺪاد ﻣﻌﯿﻨﯽ از ﺑﻠﻮك ﻫﺎي ﺟﺮﯾﺎن واﺣﺪ ﻋﻤﻞ ﻣـ ﯽ ﮐﻨـﺪ ﺑﺮاي ﺗﺼﺎدﻓﯽ ﺗﺮ ﮐﺮدن ﻫﺮ ﭼﻪ ﺑﯿﺸﺘﺮﮐﺪ ﺗﻮﻟﯿﺪي از ﯾﮏ ﻣﻮﻟﺪ ﮐﺪ ﺗﺼﺎدﻓﯽ و ﺗﻤﺎم ﺟﻤﻊ ﮐﻨﻨﺪه ﺑﻪ ﻫﻤﺮاه رﻣﺰﮔﺸﺎي 4 ﺑﻪ 16 اﺳﺘﻔﺎده ﺷﺪه اﺳﺖ. اﯾﻦ ﺗﮑﻨﯿﮏ در ﺳﺎﺧﺘﺎر ﻣﺒﺪل دﯾﺠﯿﺘﺎل ﺑﻪ آﻧﺎﻟﻮگ 10 ﺑﯿﺘﯽ ﺑﺎﯾﻨﺮي ﺑﺎ ﺗﮑﻨﻮﻟﻮژي 180 ﻧﺎﻧﻮ ﻣﺘﺮ CMOS ﭘﯿﺎده ﺳﺎزي ﺷـﺪه اﺳـﺖ، ﺟﺮﯾﺎن LSB 500 ﻧﺎﻧﻮآﻣﭙﺮ و وﻟﺘﺎژ ﺗﻐﺬﯾﻪ 1/8 وﻟﺖ و ﺗﻮان ﻣﺼﺮﻓﯽ اﯾﻦ ﻣﺒﺪل 14/6mW و ﺷﺎﺧﺺ SFDR ﻣﺒﺪل ﺑﺎ ﺷﺒﯿﻪ ﺳﺎزي ﺗﺤـﺖ ﻧﺮم اﻓﺰار Cadence Spectre 60/27 دﺳﯿﺒﻞ ﺑﻪ دﺳﺖ آﻣﺪه اﺳﺖ.

Performance of the current steering digital to analog converters are limited by transistors channel width and length mismatches and their Threshold and Early voltage variations due to fabrication process errors. Although there are several ways to reduce errors due to element mismatches, however these errors cannot be completely eliminated. In this paper, Distributed MOS Transistor Technique is utilized which facilitates Dynamic Element Matching implementation capability in Binary Digital to Analog Converter. The proposed technique reduces the errors due to element mismatches and also load voltage variations needless of high power consumption and complex circuitry. This technique operates based on random selection of unit current blocks among specific number of available current units. To make the generated code as random as possible, a random code generator, full adder and 4*16 decoder have been used. This technique is realized in a 10-bit digital to analog converter with 180 nm CMOS technology. The LSB current is 500nA and supply voltage is 1.8v and the power consumption of this converter is 14.6 mW and SFDR of DAC is achieved 60.27 dB based on simulation result with Cadence Spectre software.