December 12, 1997
7
UD61464
p
FPM Read-Write
FPM Cycle Time
t
PC
t
c(PG)RW
95
100
ns
Access Time from CAS Precharge
t
CPA
t
a(CASH)
35
40
ns
p
HIDDEN REFRESH
CAS Hold Time (CAS before RAS Cycle)
t
CHR
t
RASL-CASH
15
15
ns
Remark: see below
Dynamic Characteristics
3)
Symbol
Min.
Max.
Unit
Alt.
IEC
DC07
DC08
DC07
DC08
Remarks:
1)
The Input Low Voltage must not
drop below -0.3 V for more than
40 ns.
1a)
The total sum of the absolute
values of output currents must
not exceed 100 mA in case of
static application.
2)
The current is inversely propor-
tional to the cycle time; the max.
current is measured in the shor-
test cycle time.
3)
For test conditions see test confi-
guration for functional test and
clock timing.
4)
V
and V
are reference
levels for time measurement of
the input signals; transition times
are measured between V
IH
and
V
IL
.
5)
t
and t
define the time at
which the data output goes to
High-Z; this time is not related to
any level.
6)
t
and t
are given
as reference points only; they do
not represent restrictive conditi-
ons.
7)
The values of t
, t
and
t
cRWmin
are used for indication of
the particular cycle time in which
full function is guaranteed in the
temperature range from 0 to
70
°
C. Values below the one
shown above may cause perma-
nent damage to the component.
8)
Measured with a load equivalent
to 2 TTL loads, 100 pF.
9)
In Read cycle either t
h(RAS-R)
or
t
h(CAS-R)
must be kept.
10)
t
h(RASH-CA)
is only required if the
valid data are to be held beyond
the rising edge of RAS.
11)
t
su(W-CAS)
, t
RAS-W
, t
CAS-W
and
t
(CA-W)RW
do
restrictive parameters:
not
represent
- if t
su(W-CAS)
≥
t
su(W-CAS)min
and
t
h(CASH-W)
≥
t
h(CASH-W)min
, the
cycle is a Write cycle (CAS-con-
trolled), and the data output
remains in High-Z throughout the
whole CAS cycle,
- if t
CAS-W
> t
CAS-Wmin
, t
RAS-W
> t
RAS-Wmin
and t
(CA-W)RW
> t
(CA-
W)RWmin
, the cycle is a Read-
Write cycle, and the content of
the cell is available at the data
output,
- if none of these conditions is
satisfied, the condition of the
data output (at access time) is
indeterminate, since a Write
cycle (W-controlled) is carried
out.
12)
These parameters refer to CAS
during Write (CAS-controlled),
and to W (W-controlled) or to W
during Read-Write.
14)
t
su(W-CAS)
, t
RAS-W
, t
CAS-W
and t
(CA-
W)RW
do not represent restrictive
parameters:
- if t
su(W-CAS)
≥
t
su(W-CAS)min
the
cycle is a Write cycle (CAS-con-
trolled) and the data output
remains in High-Z throughout the
whole CAS cycle,
- if t
CAS-W
> t
CAS-Wmin
, t
RAS-W
> t
RAS-Wmin
and t
(CA-W)RW
> t
(CA-
W)RWmin
, the cycle is a Read-
Write cycle, and the content of
the cell is available at the data
output,
- if none of these conditions is
satisfied, the condition of the
data output (at access time) is
indeterminate, since a Write
cycle (W-controlled) is carried
out.