![](http://datasheet.mmic.net.cn/30000/M48T18-150PC1_datasheet_2360659/M48T18-150PC1_12.png)
Operation modes
M48T08, M48T08Y, M48T18
Table 4.
Write mode AC characteristics
2.3
Data retention mode
With valid VCC applied, the M48T08/18/08Y operates as a conventional BYTEWIDE static
RAM. Should the supply voltage decay, the RAM will automatically power-fail deselect, write
protecting itself when VCC falls within the VPFD (max), VPFD (min) window. All outputs
become high impedance, and all inputs are treated as “Don't care.”
Note:
A power failure during a WRITE cycle may corrupt data at the currently addressed location,
but does not jeopardize the rest of the RAM's content. At voltages below VPFD (min), the
user can be assured the memory will be in a write protected state, provided the VCC fall time
is not less than tF. The M48T08/18/08Y may respond to transient noise spikes on VCC that
reach into the deselect window during the time the device is sampling VCC. Therefore,
decoupling of the power supply lines is recommended.
Symbol
Parameter(1)
1.
Valid for ambient operating temperature: TA = 0 to 70°C; VCC = 4.75 to 5.5 V or 4.5 to 5.5 V (except where noted).
M48T08/M48T18/T08Y
Unit
–100/–10 (T08Y)
–150/–15 (T08Y)
MinMax
tAVAV
WRITE cycle time
100
150
ns
tAVWL
Address valid to WRITE enable low
0
ns
tAVE1L
Address valid to chip enable 1 low
0
ns
tAVE2H
Address valid to chip enable 2 high
0
ns
tWLWH
WRITE enable pulse width
80
100
ns
tE1LE1H
Chip enable 1 low to chip enable 1 high
80
130
ns
tE2HE2L
Chip enable 2 high to chip enable 2 low
80
130
ns
tWHAX
WRITE enable high to address transition
10
ns
tE1HAX
Chip enable 1 high to address transition
10
ns
tE2LAX
Chip enable 2 low to address transition
10
ns
tDVWH
Input valid to WRITE enable high
50
70
ns
tDVE1H
Input valid to chip enable 1 high
50
70
ns
tDVE2L
Input valid to chip enable 2 low
50
70
ns
tWHDX
WRITE enable high to input transition
5
ns
tE1HDX
Chip enable 1 high to input transition
5
ns
tE2LDX
Chip enable 2 low to input transition
5
ns
tWLQZ
WRITE enable low to output Hi-Z
50
70
ns
tAVWH
Address valid to WRITE enable high
80
130
ns
tAVE1H
Address valid to chip enable 1 high
80
130
ns
tAVE2L
Address valid to chip enable 2 low
80
130
ns
tWHQX
WRITE enable high to output transition
10
ns