M27C256B
Table 8B. Read Mode AC Characteristics
(1)
(T
A
= 0 to 70°C, –40 to 85°C, –40 to 105°C or –40 to 125°C; V
CC
= 5V ± 5% or 5V ± 10%; V
PP
= V
CC
)
M27C256B
Symbol
Alt
Parameter
Test Condition
-90
Min
t
AVQV
t
ELQV
t
GLQV
t
EHQZ (2)
t
GHQZ (2)
t
AXQX
t
ACC
t
CE
t
OE
t
DF
t
DF
t
OH
Address Valid to
Output Valid
Chip Enable Low to
Output Valid
Output Enable Low to
Output Valid
Chip Enable High to
Output Hi-Z
Output Enable High
to Output Hi-Z
Address Transition to
Output Transition
E = V
IL
, G = V
IL
G = V
IL
E = V
IL
G = V
IL
E = V
IL
E = V
IL
, G = V
IL
0
0
0
Max
90
90
40
30
30
0
0
0
-10
Min
Max
100
100
50
30
30
0
0
0
-12
Min
Max
120
120
60
40
40
0
0
0
-15/-20/-25 Unit
Min
Max
150
150
65
50
50
ns
ns
ns
ns
ns
ns
Note: 1. V
CC
must be applied simultaneously with or before V
PP
and removed simultaneously or after V
PP
.
2. Sampled only, not 100% tested.
Figure 5. Read Mode AC Waveforms
A0-A14
VALID
tAVQV
tAXQX
VALID
E
tGLQV
G
tELQV
Q0-Q7
tGHQZ
Hi-Z
tEHQZ
AI00758B
System Considerations
The power switching characteristics of Advance
CMOS EPROMs require careful decoupling of the
devices. The supply current, I
CC
, has three seg-
ments that are of interest to the system designer:
the standby current level, the active current level,
and transient current peaks that are produced by
the falling and rising edges of E. The magnitude of
this transient current peaks is dependent on the
capacitive and inductive loading of the device at
the output. The associated transient voltage peaks
can be suppressed by complying with the two line
6/16
output control and by properly selected decoupling
capacitors. It is recommended that a 0.1µF ceram-
ic capacitor be used on every device between V
CC
and V
SS
. This should be a high frequency capaci-
tor of low inherent inductance and should be
placed as close to the device as possible. In addi-
tion, a 4.7µF bulk electrolytic capacitor should be
used between V
CC
and V
SS
for every eight devic-
es. The bulk capacitor should be located near the
power supply connection point. The purpose of the
bulk capacitor is to overcome the voltage drop
caused by the inductive effects of PCB traces.
STMICROELECTRONICS [ STMICROELECTRONICS ]
