M68AF031A
256 Kbit (32K x 8) 5.0V Asynchronous SRAM
FEATURES SUMMARY
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SUPPLY VOLTAGE: 4.5 to 5.5V
32K x 8 bits SRAM with OUTPUT ENABLE
EQUAL CYCLE and ACCESS TIME: 55, 70ns
LOW STANDBY CURRENT
LOW V
CC
DATA RETENTION: 2V
TRI-STATE COMMON I/O
AUTOMATIC POWER DOWN
PACKAGES
– SO28, PDIP28, TSOP28 Standard and
Reverse Pinout.
– TSOP28 Standard Available in Lead-Free
Version
Figure 1. Packages
SO28 (MS)
28
1
PDIP28 (B)
TSOP28 (N)
8 x 13.4mm
TSOP28 (NS)
8 x 13.4 mm (Reverse)
November 2004
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M68AF031A
TABLE OF CONTENTS
FEATURES SUMMARY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Figure 1. Packages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
SUMMARY DESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Figure 2.
Table 1.
Figure 3.
Figure 4.
Figure 5.
Figure 6.
Figure 7.
Logic Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Signal Names . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
SO Connections. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
DIP Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
TSOP Connections (Normal) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
TSOP Connections (Reverse) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Block Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
MAXIMUM RATING. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Table 2. Absolute Maximum Ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
DC AND AC PARAMETERS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Table 3.
Figure 8.
Figure 9.
Table 4.
Table 5.
Operating and AC Measurement Conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
AC Measurement I/O Waveform . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
AC Measurement Load Circuit. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Capacitance. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
DC Characteristics (M68AF031A-55 and M68AF031A-70) . . . . . . . . . . . . . . . . . . . . . . . . 9
OPERATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Table 6. Operating Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Read Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Figure 10.Address Controlled, Read Mode AC Waveforms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Figure 11.Chip Enable or Output Enable Controlled, Read Mode AC Waveforms. . . . . . . . . . . . . 11
Figure 12.Chip Enable Controlled, Standby Mode AC Waveforms . . . . . . . . . . . . . . . . . . . . . . . . . 11
Table 7. Read and Standby Mode AC Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Write Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Figure 13.Write Enable Controlled, Write AC Waveforms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Figure 14.Chip Enable Controlled, Write AC Waveforms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Table 8. Write Mode AC Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Figure 15.Low V
CC
Data Retention AC Waveforms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Table 9. Low V
CC
Data Retention Characteristics. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
PACKAGE MECHANICAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Figure 16.SO28 - 28 lead Plastic Small Outline, 300 mils body width, Package Outline . . . . . . . . 16
Table 10. SO28 - 28 lead Plastic Small Outline, 300 mils body width, Package Mechanical Data . 16
Figure 17.PDIP28 - 28 pin Plastic DIP, 600 mils width, Package Outline . . . . . . . . . . . . . . . . . . . . 17
Table 11. PDIP28 - 28 pin Plastic DIP, n600 mils width, Package Mechanical Data . . . . . . . . . . . 17
Figure 18.TSOP28 - 28 lead Normal Pinout Plastic Small Outline, Package Outline . . . . . . . . . . . 18
Table 12. TSOP28 - 28 lead Normal Pinout Plastic Small Outline, Package Mechanical Data . . . 18
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M68AF031A
Figure 19.TSOP28 - 28 lead Reverse Pinout Plastic Small Outline, Package Outline . . . . . . . . . . 19
Table 13. TSOP28 - 28 lead Reverse Pinout Plastic Small Outline, Package Mechanical Data. . . 19
PART NUMBERING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
Table 14. Ordering Information Scheme . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
REVISION HISTORY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
Table 15. Document Revision History . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
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M68AF031A
SUMMARY DESCRIPTION
The M68AF031A is a 256 Kbit (262,144 bit) CMOS
SRAM, organized as 32,768 bytes. The device
features fully static operation requiring no external
clocks or timing strobes, with equal address ac-
cess and cycle times. It requires a single 4.5 to
5.5V supply. This device has an automatic power-
down feature, reducing the power consumption by
over 99% when deselected.
The M68AF031A is available in SO28 (28-lead
Small Outline), PDIP28 (28-pin Plastic Dual-In-
Line) and TSOP28 (28-lead Thin Small Outline,
Standard and Reverse Pinout) packages.
In addition to the standard version, the TSOP28
Standard package is also available in Lead-free
version (standard and Tape & Reel packing), in
compliance with JEDEC Std J-STD-020B, the ST
ECOPACK 7191395 Specification, and the RoHS
(Restriction of Hazardous Substances) directive. It
is also compliant with Lead-free soldering pro-
cesses.
Figure 2. Logic Diagram
Table 1. Signal Names
A0-A14
Address Inputs
Data Input/Output
Chip Enable
Output Enable
Write Enable
Supply Voltage
Ground
Not Connected Internally
VCC
DQ0-DQ7
E
16
A0-A14
W
M68AF031A
E
G
8
DQ0-DQ7
G
W
V
CC
V
SS
NC
VSS
AI05920C
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M68AF031A
Figure 3. SO Connections
Figure 5. TSOP Connections (Normal)
A5
A6
A7
A8
A9
A10
A11
A12
A13
A14
DQ0
DQ1
DQ2
VSS
1
2
3
4
5
6
7
M68AF031A
8
9
10
11
12
13
14
28
27
26
25
24
23
22
21
20
19
18
17
16
15
VCC
W
A4
A3
A2
A1
G
A0
E
DQ7
DQ6
DQ5
DQ4
DQ3
AI05921C
G
A1
A2
A3
A4
W
VCC
A5
A6
A7
A8
A9
A10
A11
22
21
28
1
M68AF031A
15
(Normal)
14
7
8
AI07200C
A0
E
DQ7
DQ6
DQ5
DQ4
DQ3
VSS
DQ2
DQ1
DQ0
A14
A13
A12
Figure 4. DIP Connections
Figure 6. TSOP Connections (Reverse)
A5
A6
A7
A8
A9
A10
A11
A12
A13
A14
DQ0
DQ1
DQ2
VSS
1
2
3
4
5
6
7
M68AF031A
8
9
10
11
12
13
14
28
27
26
25
24
23
22
21
20
19
18
17
16
15
VCC
W
A4
A3
A2
A1
G
A0
E
DQ7
DQ6
DQ5
DQ4
DQ3
A11
A10
A9
A8
A7
A6
A5
VCC
W
A4
A3
A2
A1
G
7
8
1
28
M68AF031A
(Reverse)
14
15
22
21
AI07201C
A12
A13
A14
DQ0
DQ1
DQ2
VSS
DQ3
DQ4
DQ5
DQ6
DQ7
E
A0
AI05922C
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