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LOW POWER CMOS SUB-THRESHOLD

CIRCUITS

KALYANI S. BHOSALE

ROLL NO: ME13EM05

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Introduction

 Transistor scain! " a!# od soutionto consu$%tion d#cr#as# ands%##d incr#as#.

&or t'at transistor (as o%#rat#d int'# stron! in)#rsion r#!ion.

3 o%#ratin! r#!ions o* transistor:

+#a, In)#rsion R#!ionMod#rat# In)#rsion R#!ion

Stron! In)#rsion R#!ion

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+#a, In)#rsion R#!ion

In t'is r#!ion -

∴ drain curr#nt ↓

∴ s'ort circuit dissi%ation ↓in turn r#sutin! d#cr#as# in

o%#rationa s%##d

co$%ar#d to stron! in)#rsion/

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So (' !o *or o%#ration in (#a,in)#rsion r#!ion

 Trad# o2 #t(##n s%##d and %o(#rA%%ications in ('ic' %o(#r

consu$%tion is an i$%ortant *actor

&or suc' a%%ications s%##d is not ai$itin! *actor

E!: #n#r! 'ar)#stin! a%%ications to

cr#at# s#* %o(#r#d $icrosst#$s-(ir##ss s#nsor nod#s #tc

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 T'# O%#ration R#!ions

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Fig: Alltransisto

roperatio

nregions(Courtesy:

Operationand

 Modeling of

the MOS

Transistor

2nd ed.,

Y. Tsividis)

E4u i/: A r#!ion sin!#%i#c# $od# #6%r#ssion

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+'#n o%#ratin! in t'# sut'r#s'od r#!ion- t'# drain curr#nt

is !i)#n as:

('#r# r#%r#s#nts t'# drain curr#nt('#n

and is !i)#n -

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Fig 2: IDDsub – Vds characteristics in sub-threshold operation region [1]

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7MOS In)#rt#r

Fig 3: a) C!" In#erter

b) !" transistor characteristic[1

]

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Fig $: V%C o& C!" in#erter in sub-thresholdregion [1]

 T'r#s'od )ota!# is sut'r#s'od r#!ionis otain#d in t'# sa$# (a as in stron!

in)#rsion r#!ion- #4uai8in! curr#nts

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R#%acin! and so)in! *or(# !#t-

I* t'# in)#rt#r is s$$#tric- i.#. i*

t'#n-

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Os#r)ations and7oncusions T'#r# is a co$%#t# #'a)iour anao! o*

di!ita circuits in ot' o%#ration r#!ions.

 T'# di2#r#nc# is in t'# *unctionad#%#nd#nc# o* t'# %ara$#t#rs.

In stron! in)#rsion r#!ion- t'#d#%#nd#nc# is 4uadratic- i.#. s4uar# root-and in sut'r#s'od #6%on#ntia- i.#.

o!arit'$ic.

 T'# #'a)iour anao! #na#s t'#usa!# o* t'# sa$# to%oo!i#s *or di!itacircuits in ot' o%#ration r#!ions.

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R#*#r#nc#s

[1] B. Dokic and A. Pajkanovic , “o! po!er "#os su$%threshold "ir"uits,& in Ino!"a#ion Co""$nica#ion

T%c&no'o() E'%c#!onic* Mic!o%'%c#!onic* +MIPRO, /10

0#& In#%!na#iona' Conv%n#ion on /10 22. /34.

[] 5%i' W%*#% and 6a"a!an 7 'rin"iples of CMOS S *esign8 Ed$ca#ion A*ia.

[0] 9. T*ividi* “Operation and Modeling of the MOS

Transistor& nd Ed. O:o!d Univ%!*i#) P!%** /11.

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9u#stions

 T'an, ou