AM27C2048 Datasheet, PDF (6/12 Pages) Advanced Micro Devices – 2 Megabit (128 K x 16-Bit) CMOS EPROM

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
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_CC and V_SS to minimize transient effects. In addition,
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_CC and V_SS for each eight devices. The loca-
tion of the capacitor should be close to where the
power supply is connected to the array.
MODE SELECT TABLE
Mode
Read
Output Disable
Standby (TTL)
Standby (CMOS)
Program
Program Verify
Program Inhibit
Autoselect ^{Manufacturer Code}
(Note 3)
Device Code
CE#
OE# PGM#
A0
A9
V_PP Outputs
V_IL
V_IL
X
X
X
X
D_OUT
V_IL
V_IH
X
X
X
X
High Z
V_IH
X
X
X
X
X
High Z
V_CC ± 0.3 V
X
X
X
X
X
High Z
V_IL
X
V_IL
X
X
V_PP
D_IN
V_IL
V_IL
V_IH
X
X
V_PP
D_OUT
V_IH
X
X
X
X
V_PP
High Z
V_IL
V_IL
X
V_IL
V_H
X
01h
V_IL
V_IL
X
V_IH
V_H
X
98h
Notes:
1. V_H = 12.0 V ± 0.5 V.
2. X = Either V_IH or V_IL.
3. A1–A8 and A10–16 = V_IL.
4. See DC Programming Characteristics for V_PP voltage during programming.
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Am27C2048