Cse477 23 Memories

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CSE477 L23 Memories.1 Irwin&Vijay, PSU, 2002

CSE477VLSI Dii!a" Cir#$i!s

%a"" 2002

Le#!$re 23 Semi#on'$#!orMemories

Mary Jane Irwin ( www.cse.psu.edu/~mji )www.cse.psu.edu/~cg477

[Adapted from a!aey"s Digital Integrated Circuits# $%&&%# J. a!aey et a'.

http://www.cse.psu.edu/~mji

http://www.cse.psu.edu/~cg477

http://www.cse.psu.edu/~cg477

http://www.cse.psu.edu/~mji

7/25/2019 Cse477 23 Memories



(e)iew *asi# *$i"'in *"o#+s

atapat*

+,ecution units- Adder# mu'tip'ier# diider# s*ifter# etc.

egister fi'e and pipe'ine registers

Mu'tip'e,ers# decoders

ontro' 0inite state mac*ines (12A# 3M# random 'ogic)

Interconnect

witc*es# ar!iters# !uses

Memory

ac*es (AMs)# 526s# AMs# !uffers

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econd

2ee'

ac*e

(AM)

-yi#a" Memory /ierar#y

ontro'

atapat*

econdary

Memory

(is)

3n-*ip omponents

e

g 0

i ' e

Main

Memory

(AM))

a t a

/ a c

* e

I n s t r

/ a c

* e

I 5 2 6

) 5 2 6

eAM

See' ns .8"s 8"s 8&"s 8&&"s 8#&&&"s

Sie y!es 8&&"s 9"s 8&9"s M"s 5"s

Cos! *ig*est 'owest

6y taing adantage of t*e princip'e of 'oca'ity: 1resent t*e user wit* as muc* memory as is aai'a!'e in t*e

c*eapest tec*no'ogy.

1roide access at t*e speed offered !y t*e fastest tec*no'ogy.

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Semi#on'$#!or Memories

(5M 6V(5M (M

andom Access

;on-andom Access

+13M Mas-programmed

AM

(cac*e#register fi'e)

0I03/2I03 +%13M

AM *ift egister

AM

02A< +'ectrica''y-programmed

(13M)

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9row! in D(M Ci Caa#i!y

=4

%>=

8#&&&

4#&&&

8=#&&&

=4#&&&

%>=#&&&

8&

8&&

8&&&

8&&&&

8&&&&&

8&&&&&&

8?@& 8?@% 8?@4 8?@= 8?@@ 8??& 8??% 8??4 8??= 8??@ %&&&

:ear o; in!ro'$#!ion

< 4 i ! # a . a # i ! y

7/25/2019 Cse477 23 Memories


CSE477 L23 Memories.= Irwin&Vijay, PSU, 2002

1D Memory r#i!e#!$re

ord &

ord 8

ord %

ord n-8

ord n-%

torage

e''

m !its

n w o r d

s

&

8

%

B

n-%

n-8

Input/3utput

n words → n se'ect signa's

ord &

ord 8

ord %

ord n-8

ord n-%

torage

e''

m !its

&

8

%

B

n-%

n-8

Input/3utput

A&

A8

A-8 ) e c o d

e r

ecoder reduces C of inputs

D 'og% n

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A&

o w

) e c o d e r

A8

A j-8

ense Amp'ifiers

!it 'ine

word 'ine

storage

(AM) ce''

o w A d d r e s s

/ o ' u m n

A d d r e s s

A j

A jE8

A-8

ead/rite ircuits

o'umn ecoder

%-j

m% j

Input/3utput (m !its)

amp'ifies !it 'ine swing

se'ects appropriate

word from memory row

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o w

A d d r

/ o ' u m

n

A d d

r

6 ' o c 7

A d d r

Input/3utput (m !its)

Adantages:

8. *orter word and/or !it 'ines

%. 6'oc addr actiates on'y 8 !'oc saing power

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(ea' n"y Memories (Ms

7/25/2019 Cse477 23 Memories


Pre#are' MS 6( (M

Fdd

prec*arge

2(&)

2(8)

2(%)

2(B)

G;

G;

62(&) 62(8) 62(%) 62(B)

& → 8

& → 8

8 8 8 8& 8 8 &

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MS 6( (M Layo$!

Meta'8 on top of diffusion

6asic ce''

8&λ , 7 λ

WL(0)GND (diffusion)

Meta'8

1o'ysi'icon

3n'y 8 'ayer (contact mas) is used to program memory array# so

programming of t*e 3M can !e de'ayed to one of t*e 'ast process steps.

WL(1)

WL(2)

WL(3)GND (diffusion)

BL(0) BL(1) BL(2) BL(3)

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-ransien! Mo'e" ;or 6( (M

2

62

!it

prec*arge

cword

meta'8

po'yr word

ord 'ine parasitics

esistance/ce'': B>Ω

ire capacitance/ce'': &.=> f0

Gate capacitance/ce'': >.8& f0

6it 'ine parasitics

esistance/ce'': &.8>Ω

ire capacitance/ce'': &.@B f0

rain capacitance/ce'': %.=& f0

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Proaa!ion De"ay o; 6( (M

ord 'ine de'ay

e'ay of a distri!uted rc-'ine containing M ce''stword D &.B@(r word , cword) M%

D %& nsec for M D >8%

6it 'ine de'ay Assuming min siHe pu''-down and Bmin siHe pu''-up wit*

reduced swing !it 'ines (>F to %.>F)

!it D 8.7 p0 and Ia<2 D &.B= mA so

t<2 D t2< D >.? nsec

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(ea'@5ri!e Memories (Ms

tatic AM

data is stored as 'ong as supp'y is app'ied

'arge ce''s (= fets/ce'') so fewer !its/c*ip

fast so used w*ere speed is important (e.g.# cac*es)

differentia' outputs (output 62 and K62)

use sense amps for performance

compati!'e wit* M3 tec*no'ogy

ynamic AM

periodic refres* reLuired

sma'' ce''s (8 to B fets/ce'') so more !its/c*ip s'ower so used for main memories

sing'e ended output (output 62 on'y)

need sense amps for correct operation

not typica''y compati!'e wit* M3 tec*no'ogy

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CSE477 L23 Memories.1= Irwin&Vijay, PSU, 2002

Memory -imin De;ini!ions

ead

ead yc'e

ead Access ead Access

rite

rite yc'e

ata

rite

etup

ata Fa'id

rite

<o'd

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4A4 S(M Memory

A&

o w

) e c o

d e r

K622[&

A8

A%

o'umn ecoder

sense amp'ifiers

write circuitry

62

2[8

2[%

2[B

!it 'ine prec*arge% !it words

c'ocing and

contro'

ena!'e

read

prec*arge

62[i 62[IE8

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CSE477 L23 Memories.1> Irwin&Vijay, PSU, 2002

2D Memory Con;i$ra!ion

o w

) e c o d e

r

ense Ampsense Amps

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CSE477 L23 Memories.1? Irwin&Vijay, PSU, 2002

De#reasin 5or' Line De"ay

rie t*e word 'ine from !ot* sides

se a meta' !ypass

se si'icides

po'ysi'icon word 'ine

meta' word 'ine

drier drier

2

po'ysi'icon word 'ine

meta' !ypass

2

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De#reasin *i! Line De"ay an' Enery

educe t*e !it 'ine o'tage swing

need sense amp for eac* co'umn to sense/restore signa'

Iso'ate memory ce''s from t*e !it 'ines after sensing (topreent t*e ce''s from c*anging t*e !it 'ine o'tagefurt*er) - pu'sed word 'ine

generation of word 'ine pu'ses ery critica'- too s*ort - sense amp operation may fai'

- too 'ong - power efficiency degraded (!ecause !it 'ine swing siHe dependson duration of t*e word 'ine pu'se)

use feed!ac signa' from !it 'ines

Iso'ate sense amps from !it 'ines after sensing (topreent !it 'ines from *aing 'arge o'tage swings) - !it'ine iso'ation

7/25/2019 Cse477 23 Memories



P$"se' 5or' Line %ee'a#+ Sina"

ummy co'umn *eig*t set to 8&N of a regu'ar co'umn and its ce''s are tied to

a fi,ed a'ue

capacitance is on'y 8&N of a regu'ar co'umn

ead ord 'ine

6it 'ines

omp'ete

ummy

!it 'ines

8&N

popu'ated

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P$"se' 5or' Line -imin

ummy !it 'ines *ae reac*ed fu'' swing and triggerpu'se s*ut off w*en regu'ar !it 'ines reac* 8&N swing

ead

omp'ete

ord 'ine

6it 'ine

ummy !it 'ine ∆F D Fdd

∆F D &.8Fdd

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*i! Line Iso"a!ion

sense

ead

sense

amp'ifier

!it 'ines

iso'ate

sense amp'ifier outputs

∆F D &.8Fdd

∆F D Fdd

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=@!ransis!or S(M Ce""

K62 62

2

M8

M%

MB

M4

M>

M=B

B

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CSE477 L23 Memories 28 Irwin&Vijay PSU 2002

6eA! Le#!$re an' (emin'ers ;e,t 'ecture

AM# AM# and AM cores

- eading assignment a!aey# et a'# 8%.%.%-8%.%.B

eminders 1roject fina' reports due ecem!er >t*

0ina' grading negotiations/correction (e,cept for t*e fina'e,am) must !e conc'uded !y ecem!er 8&t*

0ina' e,am sc*edu'ed

- Monday# ecem!er 8=t* from 8&:8& to noon in 88@ and 8%85*omas

Cse477 23 Memories

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