AM27C256-120DCB AMD [Advanced Micro Devices], AM27C256-120DCB Datasheet - Page 6

• Manufacturer Part Number: AM27C256-120DCB
• Description: 256 Kilobit (32 K x 8-Bit) CMOS EPRO
• Manufacturer: AMD [Advanced Micro Devices]

connection to all devices in the array and connected to
the READ line from the system control bus. This as-
sures that all deselected memory devices are in their
low-power standby mode and that the output pins are
only active when data is desired from a particular mem-
ory device.
System Applications
During the switch between active and standby condi-
tions, transient current peaks are produced on the ris-
ing and falling edges of Chip Enable. The magnitude of
MODE SELECT TABLE
Notes:
1. V
2. X = Either V
3. A1–A8 and A10–14 = V
4. See DC Programming Characteristics for V
6
Mode
Read
Output Disable
Standby (TTL)
Standby (CMOS)
Program
Program Verify
Program Inhibit
Autoselect
(Note 3)
H
= 12.0 V
Manufacturer Code
Device Code
IH
0.5 V.
or V
IL
.
IL
V
CC
PP
CE#
V
V
V
V
V
V
V
voltage during programming.
X
IH
IH
IL
IL
IL
IL
IL
0.3 V
Am27C256
OE#
V
V
V
V
V
V
X
X
X
IH
IH
IL
IL
IL
IL
these transient current peaks is dependent on the out-
put capacitance loading of the device. At a minimum, a
0.1 µF ceramic capacitor (high frequency, low inherent
inductance) should be used on each device between
V
to overcome the voltage drop caused by the inductive
effects of the printed circuit board traces on EPROM ar-
rays, a 4.7 µF bulk electrolytic capacitor should be used
between V
tion of the capacitor should be close to where the
power supply is connected to the array.
CC
and V
V
A0
V
X
X
X
X
X
X
X
CC
IH
SS
IL
and V
to minimize transient effects. In addition,
SS
A9
V
V
X
X
X
X
X
X
X
for each eight devices. The loca-
H
H
V
V
V
V
X
X
X
X
X
X
PP
PP
PP
PP
Outputs
High Z
High Z
High Z
High Z
D
D
01h
10h
D
OUT
OUT
IN