M48T02(1998) 데이터 시트보기 (PDF) - STMicroelectronics
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M48T02 Datasheet PDF : 15 Pages
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M48T02, M48T12
Table 10. Write Mode AC Characteristics
(TA = 0 to 70°C; VCC = 4.75V to 5.5V or 4.5V to 5.5V)
Symbol
Parameter
M48T02 / M48T12
-70
-150
-200
Min Max Min Max Min Max
tAVAV
Write Cycle Time
70
150
200
tAVWL
Address Valid to Write Enable Low
0
0
0
tAVEL
Address Valid to Chip Enable Low
0
0
0
tWLWH
Write Enable Pulse Width
50
tELEH
Chip Enable Low to Chip Enable High
55
90
120
90
120
tWHAX
Write Enable High to Address Transition
0
10
10
tEHAX
Chip Enable High to Address Transition
0
10
10
tDVWH
Input Valid to Write Enable High
30
40
60
tDVEH
Input Valid to Chip Enable High
30
40
60
tWHDX
Write Enable High to Input Transition
5
5
5
tEHDX
Chip Enable High to Input Transition
5
5
5
tWLQZ
tAVWH
Write Enable Low to Output Hi-Z
Address Valid to Write Enable High
25
50
60
60
120
140
tAVEH
Address Valid to Chip Enable High
60
120
140
tWHQX
Write Enable High to Output Transition
5
10
10
Unit
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
READ MODE
The M48T02/12 is in the Read Mode whenever W
(Write Enable) is high and E (Chip Enable) is low.
The device architecture allows ripple-through ac-
cess of data from eight of 16,384 locations in the
static storage array. Thus, the unique address
specified by the 11 Address Inputs defines which
one of the 2,048 bytes of data is to be accessed.
Valid data will be available at the Data I/O pins
within Address Access time (tAVQV) after the last
address input signal is stable, providing that the E
and G access times are also satisfied. If the E and
G access times are not met, valid data will be
available after the latter of the Chip Enable Access
time (tELQV) or Output Enable Access time (tGLQV).
The state of the eight three-state Data I/O signals
is controlled by E and G. If the outputs are activated
before tAVQV, the data lines will be driven to an
indeterminate state until tAVQV. If the Address In-
puts are changed while E and G remain active,
output data will remain valid for Output Data Hold
time (tAXQX) but will go indeterminate until the next
Address Access.
WRITE MODE
The M48T02/12 is in the Write Mode whenever W
and E are active. The start of a write is referenced
from the latter occurring falling edge of W or E. A
write is terminated by the earlier rising edge of W
or E. The addresses must be held valid throughout
the cycle. E or W must return high for a minimum
of tEHAX from Chip Enable or tWHAX from Write
Enableprior to the initiation of anotherread or write
cycle. Data-in must be valid tDVWH prior to the end
of write and remain valid for tWHDX afterward. G
shouldbe kept high during write cycles to avoid bus
contention; although, if the output bus has been
activated by a low on E and G, a low on W will
disable the outputs tWLQZ after W falls.
7/15
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