February 6, 2004
Am42DL16x2D
53
AC CHARACTERISTICS
SRAM Write Cycle
Notes:
1. WE# controlled, if CIOs is low, ignore UB#s and LB#s timing.
1. t
CW
is measured from CE1#s going low to the end of write.
2. t
WR
is measured from the end of write to the address change. t
WR
applied in case a write ends as CE1#s or WE# going high.
3. t
AS
is measured from the address valid to the beginning of write.
4. A write occurs during the overlap (t
WP
) of low CE#1 and low WE#. A write begins when CE1#s goes low and WE# goes low when
asserting UB#s or LB#s for a single byte operation or simultaneously asserting UB#s and LB#s for a double byte operation. A
write ends at the earliest transition when CE1#s goes high and WE# goes high. The t
WP
is measured from the beginning of write
to the end of write.
Figure 30.
SRAM Write Cycle—WE# Control
Parameter
Symbol
Description
Speed Options
Unit
70
85
t
WC
Write Cycle Time
Min
70
85
ns
t
Cw
Chip Enable to End of Write
Min
60
70
ns
t
AS
Address Setup Time
Min
0
ns
t
AW
Address Valid to End of Write
Min
60
70
ns
t
BW
UB#s, LB#s to End of Write
Min
60
70
ns
t
WP
Write Pulse Time
Min
50
60
ns
t
WR
Write Recovery Time
Min
0
ns
t
WHZ
Write to Output High-Z
Min
0
ns
Max
20
25
t
DW
Data to Write Time Overlap
Min
30
35
ns
t
DH
Data Hold from Write Time
Min
0
ns
t
OW
End Write to Output Low-Z
Min
5
ns
Address
CE1#s
Data Undefined
UB#s, LB#s
WE#
Data In
Data Out
t
WC
t
CW
(See Note 2)
t
AW
High-Z
High-Z
Data Valid
CE2s
t
CW
(See Note 2)
t
BW
t
WP
(See Note 5)
t
AS
(See Note 4)
t
WR
(See Note 3)
t
WHZ
t
DW
t
DH
t
OW