w27c020 Winbond Electronics Corp America, w27c020 Datasheet - Page 3

• Manufacturer Part Number: w27c020
• Description: 256k X 8 Electrically Erasable Eprom
• Manufacturer: Winbond Electronics Corp America

Standby Mode
The standby mode significantly reduces V
standby mode, all outputs are in a high impedance state, independent of OE and PGM.
Two-line Output Control
Since EPROMs are often used in large memory arrays, the W27C020 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
concerned with three supply current issues: standby current levels (I
and 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
PP
Read
Output Disable
Standby (TTL)
Standby (CMOS)
Program
Program Verify
Program Inhibit
Erase
Erase Verify
Erase Inhibit
Product Identifier-
manufacturer
Product Identifier-device
= 12V, V
PE
CC
MODE
= 14V, V
and GND. The bulk capacitor will overcome voltage slumps caused by PC board trace
F electrolytic capacitor should be placed at the array's power supply connection
HH
= 12V, V
CP
= 5V, V
V
CC
CE
V
V
V
V
V
V
V
V
V
V
V
CE
IH
IH
IH
IL
IL
IL
IL
IL
IL
IL
IL
0.3V
= 5V, V
CC
ID
OE
V
V
V
V
V
V
V
V
= 14V, X = V
X
X
X
X
IH
IL
IL
IL
IL
IL
IH
IH
current. This mode is entered when CE = V
- 3 -
PGM
CC
V
V
V
V
X
X
X
X
X
X
X
X
IH
IH
IL
IL
and GND. This high frequency, low inherent-
IH
or V
V
V
V
A0
IL
X
X
X
X
X
X
X
X
X
Publication Release Date: September 1998
IH
Preliminary W27C020
IL
IL
PINS
V
V
V
A9
X
X
X
X
X
X
X
X
X
HH
HH
ID
SB
), active current levels (I
V
V
V
V
V
V
V
V
V
V
V
V
V
CC
CC
CC
CC
CC
CC
CC
CC
CC
CP
CP
CE
CE
V
V
V
V
V
V
V
V
V
V
V
V
V
CC
CC
CC
CC
CC
CC
PP
PP
PP
PP
PE
PE
PE
D
High Z
High Z
High Z
D
D
High Z
FF (Hex)
D
High Z
DA (Hex)
85 (Hex)
OUTPUTS
OUT
IN
OUT
OUT
Revision A1
IH
CC
. In
),