W27E257-15 WINBOND [Winbond], W27E257-15 Datasheet - Page 3

• Manufacturer Part Number: W27E257-15
• Description: 32K X 8 ELECTRICALLY ERASABLE EPROM
• Manufacturer: WINBOND [Winbond]

Standby Mode
The standby mode significantly reduces V
standby mode, all outputs are in a high impedance state, independent of OE.
Two-line Output Control
Since EPROMs are often used in large memory arrays, the W27E257 provides two control inputs for
multiple memory connections. Two-line control provides for lowest possible memory power
dissipation and ensures that data bus contention will not occur.
System Considerations
EPROM power switching characteristics require careful device decoupling. System designers are
interested in three supply current issues: standby current levels (I
transient current peaks produced by the falling and rising edges of CE. Transient current magnitudes
depend on the device output's capacitive and inductive loading. Two-line control and proper
decoupling capacitor selection will suppress transient voltage peaks. Each device should have a 0.1
F ceramic capacitor connected between its V
inductance capacitor should be placed as close as possible to the device. Additionally, for every eight
devices, a 4.7
between V
inductances.
TABLE OF OPERATING MODES
(V
Read
Output Disable
Standby (TTL)
Standby (CMOS)
Program
Program Verify
Program Inhibit
Erase
Erase Verify
Erase Inhibit
Product Identifier-manufacturer
Product Identifier-device
PP
= 12V, V
CC
PE
= 14V, V
and GND. The bulk capacitor will overcome voltage slumps caused by PC board trace
MODE
F electrolytic capacitor should be placed at the array's power supply connection
HH
= 12V, V
CP
= 5V, X = V
V
CC
V
V
V
V
V
IH
CE
V
V
V
V
V
V
IH
IH
IH
IH
IH
IL
IL
IL
IL
IL
IL
or V
0.3V
CC
IL
)
current. This mode is entered when CE = V
CC
- 3 -
OE
V
V
V
V
V
V
V
V
V
V
X
X
IH
IH
IH
IH
IH
IL
IL
IL
IL
IL
and GND. This high frequency, low inherent-
V
V
V
A0
X
X
X
X
X
X
X
X
X
IH
IL
IL
Publication Release Date: January 1997
V
V
PINS
V
SB
A9
X
X
X
X
X
X
X
X
X
HH
HH
PE
), active current levels (I
V
V
V
V
V
V
V
V
V
V
V
V
V
CC
CC
CC
CC
CC
CP
CP
CP
CC
CC
CP
CC
CC
V
V
V
V
V
V
V
V
V
V
V
V
V
CC
CC
CC
CC
PP
PP
PP
PE
PE
PP
CC
CC
PP
W27E257
D
High Z
High Z
High Z
D
D
High Z
D
D
High Z
DA (Hex)
02 (Hex)
OUTPUTS
OUT
IN
OUT
IH
OUT
Revision A3
CC
), and
IH
. In