Spectravideo SVI 318 Service – Technical Manual page 79

x
1 6384 1 BIT DYNAMIC MOS RANDOM ACCESS
The 4 1 1 6 i s a 1 63 8 4 wo r d s b y 1 b i t Dy nam i c MOS
ap p l i c a t i o n s whe re ve r y l ow co s t and l a rg e b i t s t o r a g e a re impor t a n t de s i g n
ob j e c t i v e s .
wh i c h
t h e 4 1 1 6 i s f ab r i c a t e d u s i ng a d ou b l e-po l y - l a y e r
dy na m i c
a f f o r d s h i gh s t o r a g e ce l l d e n s i t y and h igh pe r f o rmance .
c i r c u i t r y t h rougho u t ,
pow e r d i s s i pa t i on .
Mu l t i p l e x e d a dd re s s in p u t s p e rm i t t h e 4 1 1 6 to be pa c k a g e d i n the s t a nd a r d 1 6
p i n du a l - i n- l i ne packa g e .
t i m i n g
d e n s i t i e s and i s av a i l a b l e i n e i t h e r ce ram i c o r p l a s t i c "
re q u i remen t s a l l ow u s e o f t he mu l t i p l e x ing t ec h n i que wh i l e ma i n t a i n ing
h i gh p e r f o rmance .
x
1
65 53 6 B IT DYNAMIC MOS
The 4 86 4 ut i l i z e s a t h r e e - po l y N-channe l s i l i c on g a t e p roc e s s wh i c h p rov i d e s
h i gh s t o rage c e l l d e n s i t y , h i gh p e r f o rmance and h i gh re l i ab i l i t y .
The 486 4 us e s a s i ng l e t r a n s i s t o r dynam ic s t o r a ge ce l t a n d a dvan c e d dy nam i c
c i rc u i t r y t h roughou t ,
p o w e r d i s s i pa t i o n i s m i n i m i z e d .
max i m i z e y i e l d ( low c o s t to us e r ) wh i l e ma i n t a i n i ng comp a t i b i l i t y between
Dy na m i c RAM gen e r a t i o n s .
The 4 8 64 t h r e e - s t a te ou t pu t i s c o n t ro l l e d by CAS ,
va l i d re a d or r e a d-mo d i f y -w r i t e c yc l e , d a t a i s he l d on the ou t p u t by ho l d i ng
CAS l o w . The d a t a ou t p i n i s re t u rne d to the h i gh i mp e n d a n c e s t a t e b y
re t u rn i n g CAS t o a h i gh s t a t e .
CAS t o be he l d l ow to ma i n t a i n ou t p u t d a ta wh i l e RAS is used t o e x e c u t e d RAS
on l y re f re sh c yc l e s .
Re f r e sh ing i s ac comp l i s he d b y p e r f o rm ing RAS o n l y re f r e sh c yc l e s , h id d e n
re f r� s h c y c l e s , o r no rma l re a d o r w r i t e c yc l e s on the 1 2 8 a d d re s s comb i n a t iuns
o f A 0 t h rou gh A 6
Mu l t i p l e x e d a dd re s s i n p u t s pe rm i t the 4864 t o be pa c k a g e d i n the s t an d a r d
p i n d u a l - i n- l i ne packa g e .
d e n s i t i e s a n d i s compa t i b l e w i t h wi d e l y a va i l a b l e a u to ma t e d han d l i n g e q u i pmen t .
i n c l u d i ng the s e n s e
T he 1 6 p in package p ro v i d e s the h i ghe s t s y s tem b i t
RANDOM
ACCES S MEMORY ( 4864)
i n c l u d i ng t he 5 1 2 s e n s e amp l i f i e r s , wh i c h a s su r e s t ha t
Re f re s h cha r a c t e r i s t i c s have be e n cho s e n t o
The 4864 h id d e n re f r e s h f e a t u re a l l ows
du r ing a 2 ms p e r i od .
The 1 6 p i n package p ro v i d e s the h i ghe s t s y s t em b i t
4 . 46
�!EMORY ( 41 1 6 )
RAM .
I t i s d e s i gne d f o r mem o r y
N- c h a n n e l
am p l i f i e r s ,
ind ep e n d e nt of RAS .
s i l i c on g a t e p roc e s s
The u s e of
a s s u re s m i n i ma l
N o nc r i t i c a l c l o c k
A f t e r a
1 6