White Electronic Designs
256Kx8 Monolithic SRAM
FEATURES
256Kx8 CMOS Static
Random Access Memory
• Access Times of 70, 85, 100ns
• Data Retention Function (LP Versions)
• TTL Compatible Inputs and Outputs
• Fully Static, No Clocks
JEDEC Approved Pinout
• 32 pin Ceramic DIP, 0.6 mils wide (Package 9)
■
Single +5V (±10%) Supply Operation
EDI88257C
The EDI88257C is a 2 Megabit 256Kx8 bit Monolithic
CMOS Static RAM.
The 32 pin DIP pinout adheres to the JEDEC standard for
the two megabit device, and is a pin replacement for the
256Kx8 module, EDI88257C. The device is upgradeable
to the 512Kx8 SRAM, the EDI88512C. Pin 1 becomes the
higher order address.
A Low Power version, EDI88257LP, offers a data retention
function for battery back-up opperation. Military product is
available compliant to Appendix A of MIL-PRF-38535.
FIGURE 1 – PIN CONFIGURATION
32 DIP
PIN DESCRIPTION
32
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
V
CC
A15
A17
W#
A13
A8
A9
A11
G#
A10
E#
I/O7
I/O6
I/O5
I/O4
I/O3
A0-17
TOP VIEW
NC
A16
A14
A12
A7
A6
A5
A4
A3
A2
A1
A0
DQ0
DQ1
DQ2
V
SS
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
A0-17
W#
E#
G#
DQ0-7
V
CC
V
SS
NC
Address Inputs
Write Enable
Chip Enable
Output Enable
Data Inputs/Outputs
Power (+5V ±10%)
Ground
Not Connected
BLOCK DIAGRAM
Memory Array
Address
Buffer
Address
Decoder
I/O
Circuits
DQ0-7
W#
E#
G#
White Electronic Designs Corp. reserves the right to change products or specifications without notice.
September 1999
Rev. 2
1
White Electronic Designs Corporation • (602) 437-1520 • www.wedc.com
White Electronic Designs
ABSOLUTE MAXIMUM RATINGS
Parameter
Voltage on any pin relative to Vss
Operating Temperature T
A
(Ambient)
Industrial
Military
Storage Temperature, Plastic
Power Dissipation
Output Current
Junction Temperature, T
J
Value
-0.5 to 7.0
-40 to +85
-55 to +125
-65 to +150
1
20
175
Unit
V
°C
°C
°C
W
mA
°C
G#
X
H
L
X
E#
H
L
L
L
W#
X
H
H
L
Mode
Standby
Output Deselect
Read
Write
EDI88257C
TRUTH TABLE
Output
High Z
High Z
Data Out
Data In
Power
I
CC2
, I
CC3
I
CC1
I
CC1
I
CC1
RECOMMENDED OPERATING CONDITIONS
Parameter
Supply Voltage
Supply Voltage
Input High Voltage
Input Low Voltage
Symbol
V
CC
V
SS
V
IH
V
IL
Min
4.5
0
2.2
-0.3
Typ
5.0
0
—
—
Max
5.5
0
V
CC
+0.5
+0.8
Unit
V
V
V
V
NOTE:
Stress greater than those listed under “Absolute Maximum Ratings” may cause
permanent damage to the device. This is a stress rating only and functional operation
of the device at these or any other conditions greater than those indicated in the
operational sections of this specification is not implied. Exposure to absolute maximum
rating conditions for extended periods may affect reliability.
CAPACITANCE
Parameter
Address Lines
Data Lines
Symbol
C
I
C
O
Condition
V
IN
= Vcc or Vss, f = 1.0MHz
V
OUT
= Vcc or Vss, f = 1.0MHz
Max
30
14
Unit
pF
pF
These parameters are sampled, not 100% tested.
DC CHARACTERISTICS
V
CC
= 5V, T
A
= +25°C
Parameter
Input Leakage Current
Output Leakage Current
Operating Power Supply Current
Standby (TTL) Power Supply Current
Full Standby Power Supply Current
Output Low Voltage
Output High Voltage
Symbol
I
LI
I
LO
I
CC1
I
CC2
I
CC3
V
OL
V
OH
Conditions
V
IN
= 0V to V
CC
V
I/O
= 0V to V
CC
W#, E# = V
IL
, I
I/O
= 0mA, Min Cycle (70-100ns)
E# ≥ V
IH
, V
IN
≤ V
IL
, V
IN
≥ V
IH
C
E# ≥ V
CC
-0.2V
V
IN
≥ Vcc -0.2V or V
IN
≤ 0.2V
LP
I
OL
= 2.1mA
I
OH
= -1.0mA
Min
—
—
—
—
—
—
—
2.4
Typ
—
—
45
3
—
—
—
—
Max
±10
±10
75
10
5
1
0.4
—
Units
µA
µA
mA
mA
mA
mA
V
V
AC TEST CONDITIONS
Figure 1
Vcc
Figure 2
Input Pulse Levels
Vcc
V
SS
to 3.0V
5ns
1.5V
Figure 1
Input Rise and Fall Times
Input and Output Timing Levels
480Ω
480Ω
Output Load
Q
255Ω
30pF
Q
255Ω
5pF
NOTE: For t
EHQZ
, t
GHQZ
and t
WLQZ
, CL = 5pF Figure 2
White Electronic Designs Corp. reserves the right to change products or specifications without notice.
September 1999
Rev. 2
2
White Electronic Designs Corporation • (602) 437-1520 • www.wedc.com
White Electronic Designs
AC CHARACTERISTICS – READ CYCLE
V
CC
= 5.0V, Vss = 0V, -55°C
≤
T
A
≤
+125°C
70ns
Alt.
t
RC
t
AA
t
ACS
t
CLZ
t
CHZ
t
OH
t
OE
t
OLZ
t
OHZ
Min
70
Max
70
70
10
25
10
35
5
0
25
5
0
10
45
30
5
0
10
30
10
Min
85
Symbol
Parameter
Read Cycle Time
Address Access Time
Chip Enable Access Time
Chip Enable to Output in Low Z (1)
Chip Disable to Output in High Z (1)
Output Hold from Address Change
Output Enable to Output Valid
Output Enable to Output in Low Z (1)
Output Disable to Output in High Z(1)
1. This parameter is guaranteed by design but not tested.
EDI88257C
85ns
Max
85
85
10
Min
100
100ns
Max
100
100
30
50
30
Units
ns
ns
ns
ns
ns
ns
ns
ns
ns
JEDEC
t
AVAV
t
AVQV
t
ELQV
t
ELQX
t
EHQZ
t
AVQX
t
GLQV
t
GLQX
t
GHQZ
AC CHARACTERISTICS – WRITE CYCLE
V
CC
= 5.0V, V
SS
= 0V, -55°C≤ T
A
≤
+125°C
70ns
Alt.
t
WC
t
CW
t
CW
t
AS
t
AS
t
AW
t
AW
t
WP
t
WP
t
WR
t
WR
t
DH
t
DH
t
WHZ
t
DW
t
DW
t
WLZ
Min
70
60
60
0
0
65
65
50
50
0
0
0
0
0
40
30
5
Max
Min
85
70
70
0
0
70
70
55
55
0
0
0
0
0
40
35
0
Symbol
Parameter
Write Cycle Time
Chip Enable to End of Write
Address Setup Time
Address Valid to End of Write
Write Pulse Width
Write Recovery Time
Data Hold Time
Write to Output in High Z (1)
Data to Write Time
Output Active from End of Write (1)
1. This parameter is guaranteed by design but not tested.
85ns
Max
Min
100
80
80
0
0
80
80
60
60
0
0
0
0
0
40
40
0
100ns
Max
Units
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
JEDEC
t
AVAV
t
ELWH
t
ELEH
t
AVWL
t
AVEL
t
AVWH
t
AVEH
t
WLWH
t
WLEH
t
WHAX
t
EHAX
t
WHDX
t
EHDX
t
WLQZ
t
DVWH
t
DVEH
t
WHQX
25
30
30
White Electronic Designs Corp. reserves the right to change products or specifications without notice.
September 1999
Rev. 2
3
White Electronic Designs Corporation • (602) 437-1520 • www.wedc.com
White Electronic Designs
FIGURE 2 – TIMING WAVEFORM - READ CYCLE
t
AVAV
ADDRESS
EDI88257C
t
AVQV
E#
t
AVAV
ADDRESS
ADDRESS 1
ADDRESS 2
t
ELQV
t
ELQX
G#
t
EHQZ
t
AVQV
DATA I/O
t
AVQX
DATA 1
DATA 2
t
GLQV
t
GLQX
DATA OUT
t
GHQZ
READ CYCLE 1 (W# HIGH; G#, E# LOW)
READ CYCLE 2 (W# HIGH)
FIGURE 3 – WRITE CYCLE - W# CONTROLLED
t
AVAV
ADDRESS
t
AVWH
t
ELWH
E#
t
WHAX
t
AVWL
W#
t
WLWH
t
DVWH
t
WHDX
DATA IN
DATA VALID
t
WLQZ
DATA OUT
HIGH Z
t
WHQX
WRITE CYCLE 1, W# CONTROLLED
FIGURE 4 – WRITE CYCLE - E# CONTROLLED
t
AVAV
ADDRESS
t
AVEH
t
ELEH
E#
t
EHAX
t
AVEL
W#
t
WLEH
t
DVEH
t
EHDX
DATA IN
DATA OUT
HIGH Z
DATA VALID
WRITE CYCLE 2, E# CONTROLLED
White Electronic Designs Corp. reserves the right to change products or specifications without notice.
September 1999
Rev. 2
4
White Electronic Designs Corporation • (602) 437-1520 • www.wedc.com
White Electronic Designs
DATA RETENTION CHARACTERISTICS (EDI88257LP ONLY)
-55°C
≤
T
A
≤
+125°C
Characteristic
Low Power Version only
Data Retention Voltage
Data Retention Quiescent Current
Chip Disable to Data Retention Time
Operation Recovery Time
Sym
V
CC
I
CCDR
t
CDR
T
R
Conditions
V
CC
= 2.0V
E# ≥ V
CC
-0.2V
V
IN
≥ V
CC
-0.2V
or V
IN
≤ 0.2V
Min
2
–
0
t
AVAV
Typ
–
–
–
–
EDI88257C
Max
–
185
–
–
Units
V
µA
ns
ns
FIGURE 5 – DATA RETENTION - E# CONTROLLED
DATA RETENTION MODE
V
CC
t
CDR
E#
E# = V
CC
-0.2V
4.5V
V
CC
4.5V
t
R
DATA RETENTION, E# CONTROLLED
White Electronic Designs Corp. reserves the right to change products or specifications without notice.
September 1999
Rev. 2
5
White Electronic Designs Corporation • (602) 437-1520 • www.wedc.com
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