W27E257
32K
×
8 ELECTRICALLY ERASABLE EPROM
GENERAL DESCRIPTION
The W27E257 is a high-speed, low-power Electrically Erasable and Programmable Read Only
Memory organized as 32768
×
8 bits that operates on a single 5 volt power supply. The W27E257
provides an electrical chip erase function. This part was the same EPROM Writer's utilities as the
W27E256.
FEATURES
•
High speed access time:
•
•
•
•
100/120/150 nS (max.)
Read operating current: 15 mA (typ.)
Erase/Programming operating current
1 mA (typ.)
Standby current: 5
µA
(typ.)
Single 5V power supply
•
+14V erase/+12V programming voltage
•
Fully static operation
•
All inputs and outputs directly TTL/CMOS
compatible
•
Three-state outputs
•
Available packages: 28-pin 600 mil DIP and
32-pin PLCC
PIN CONFIGURATIONS
V
PP
A12
A7
A6
A5
A4
A3
A2
A1
A0
Q0
Q1
Q2
GND
1
2
3
4
5
6
7
8
9
10
11
12
13
14
28-pin
DIP
28
27
26
25
24
23
22
21
20
19
18
17
16
15
V
CC
A14
A13
A8
A9
A11
OE
A10
CE
Q7
Q6
Q5
Q4
Q3
BLOCK DIAGRAM
Q0
.
.
Q7
CE
OE
CONTROL
OUTPUT
BUFFER
A0
.
.
A14
VCC
GND
VPP
DECODER
CORE
ARRAY
A V
V A A
A 1 P N C 1 1
7 2 P C C 4 3
4 3 2
A6
A5
A4
A3
A2
A1
A0
NC
Q0
5
6
7
8
9
10
11
12 1
13 4
1
3
2
3
1
3
0 29
28
27
26
25
24
23
22
2
0 21
PIN DESCRIPTION
A8
A9
A11
NC
OE
A10
CE
Q7
Q6
SYMBOL
A0−A14
Q0−Q7
CE
OE
V
PP
V
CC
GND
NC
32-pin
PLCC
1
5
1
6
1 1
7 8
1
9
Q Q G N
1 2 N C
D
Q Q Q
3 4 5
DESCRIPTION
Address Inputs
Data Inputs/Outputs
Chip Enable
Output Enable
Program/Erase Supply Voltage
Power Supply
Ground
No Connection
Publication Release Date: January 1997
Revision A3
-1-
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