Ordering number : ENN
*
6302
52600RM (OT) No. 6302-1/7
Overview
The LC35256FM and LC35256FT are asynchronous
silicon-gate CMOS SRAMs with a 32K-word by 8-bit
structure. These are full-CMOS devices with 6 transistors
per memory cell, and feature low-voltage operation, a low
operating current drain, and an ultralow standby current.
Control inputs include OE for fast memory access and CE
(chip enable) for power saving and device selection. This
makes these devices optimal for systems that require low
power or battery backup, and makes memory expansion
easy. The ultralow standby current allows these devices to
be used with capacitor backup as well.
Features
Supply voltage range: 4.5 to 5.5 V
Access time at 5 V operation:
LC35256FM, FT-55U: 55 ns (maximum)
LC35256FM, FT-70U: 70 ns (maximum)
Standby current: 3.0 A (Ta
70C)
5.0 A (Ta
85C)
Operating temperature: 40 to +85C
Data retention voltage: 2.0 to 5.5 V
All I/O levels: TTL compatible
Input/output shared function pins, 3-state output pins
No clock required
Package
28-pin SOP (450 mil) plastic package: LC35256FM
28-pin TSOP (8
13.4 mm) plastic package: LC35256FT
Package Dimensions
unit: mm
3187A-SOP28D
unit: mm
3221-TSOP28 (Type I)
Preliminary
LC35256FM, FT-55U/70U
SANYO Electric Co.,Ltd. Semiconductor Company
TOKYO OFFICE Tokyo Bldg., 1-10, 1 Chome, Ueno, Taito-ku, TOKYO, 110-8534 JAPAN
256K (32768 words
8 bits) SRAM
Control Pins: OE and CE
CMOS IC
1
14
15
28
11.8
1.0
8.4
9.8
18.0
0.1 2.3
1.27
0.4
0.15
SANYO: SOP28D
[LC35256FM]
Any and all SANYO products described or contained herein do not have specifications that can handle
applications that require extremely high levels of reliability, such as life-support systems, aircraft's
control systems, or other applications whose failure can be reasonably expected to result in serious
physical and/or material damage. Consult with your SANYO representative nearest you before using
any SANYO products described or contained herein in such applications.
SANYO assumes no responsibility for equipment failures that result from using products at values that
exceed, even momentarily, rated values (such as maximum ratings, operating condition ranges, or other
parameters) listed in products specifications of any and all SANYO products described or contained
herein.
0.55
22
7
21
8
1
28
8.1
1.27max
11.8
13.4
0.5
0.2
0.125
0.08
SANYO: TSOP28 (Type I)
[LC35256FT]
Pin Functions
No. 6302-3/7
LC35256FM, FT-55U/70U
A0 to A14
Address input
WE
Read/write control input
OE
Output enable input
CE
Chip enable input
I/O1 to I/O8
Data I/O
V
CC
, GND
Power supply, ground
Function Table
Mode
CE
OE
WE
I/O
Supply current
Read cycle
L
L
H
Data output
I
CCA
Write cycle
L
X
L
Data input
I
CCA
Output disable
L
H
H
High impedance
I
CCA
Unselected
H
X
X
High impedance
I
CCS
Parameter
Symbol
Conditions
Ratings
Unit
Maximum supply voltage
V
CC
max
7.0
V
Input pin voltage
V
IN
0.3
*
to V
CC
+ 0.3
V
I/O pin voltage
V
I/O
0.3 to V
CC
+ 0.3
V
Operating temperature
Topr
40 to +85
C
Storage temperature
Tstg
55 to +125
C
Specifications
Absolute Maximum Ratings
Note:
*
The minimum value is 3.0 V for pulse widths under 30 ns.
I/O Capacitances
at Ta = 25C, f = 1 MHz
Parameter
Symbol
Conditions
Ratings
Unit
min
typ
max
I/O pin capacitance
C
I/O
V
I/O
= 0 V
6
10
pF
Input pin capacitance
C
I
V
IN
= 0 V
6
10
pF
Note: All units are not tested; only samples are tested.
DC Allowable Operating Ranges
at Ta = 40 to +85C, V
CC
= 4.5 to 5.5 V
Parameter
Symbol
Conditions
Ratings
Unit
min
typ
max
Supply voltage
V
CC
4.5
5.0
5.5
V
Input voltage
V
IH
2.2
V
CC
+ 0.3
V
V
IL
0.3
*
+0.8
V
Note:
*
The minimum value is 3.0 V for pulse widths under 30 ns.
No. 6302-4/7
LC35256FM, FT-55U/70U
DC Electrical Characteristics
at Ta = 40 to +85C, V
CC
= 4.5 to 5.5 V
Parameter
Symbol
Conditions
Ratings
Unit
min
typ
*
max
Input leakage current
I
LI
V
IN
= 0 to V
CC
1.0
+1.0
A
Output leakage current
I
LO
V
CE
= V
IH
or V
OE
= V
IH
or V
WE
= V
IL
,
1.0
+1.0
A
V
I/O
= 0 to V
CC
Output high-level voltage
V
OH
I
OH
= 1.0 mA
2.4
V
Output low-level voltage
V
OL
I
OL
= 2.0 mA
0.4
V
I
CCA2
V
CE
= V
IL
, I
I/O
= 0 mA, V
IN
= V
IH
or V
IL
5.0
mA
Operating current drain
LC35256FM, FT-55U
40
45
I
CCA3
LC35256FM, FT-70U
35
40
mA
1 s cycle
3.5
6.0
Ta
25C
0.05
Standby mode
I
CCS1
Ta
60C
1.5
A
current drain
Ta
70C
3.0
Ta
85C
5.0
I
CCS2
V
CE
= V
IH
, V
IN
= 0 to V
CC
1.0
mA
Note:
*
Reference values when V
CC
= 5 V and Ta = 25C.
TTL inputs
V
CE
V
CC
0.2 V,
V
IN
= 0 to V
CC
V
CC
0.2 V/
0.2 V inputs
TTL inputs
AC Electrical Characteristics
at Ta = 40 to +85C, V
CC
= 4.5 to 5.5 V
AC test conditions
Input pulse voltage levels: V
IH
= 2.4 V
,
V
IL
= 0.6 V
Input rise and fall times: 5 ns
Input and output timing levels: 1.5 V
Output load: 30 pF + 1 TTL gate (including the jig capacitance)
LC35256FM, FT
Parameter
Symbol
-55U
-70U
Unit
min
max
min
max
Read cycle time
t
RC
55
70
ns
Address access time
t
AA
55
70
ns
CE access time
t
CA
55
70
ns
OE access time
t
OA
30
35
ns
Output hold time
t
OH
10
10
ns
CE output enable time
t
COE
5
10
ns
OE output enable time
t
OOE
5
5
ns
CE output disable time
t
COD
20
30
ns
OE output disable time
t
OOD
20
25
ns
Read Cycle
Write Cycle
V
CE
= V
IL
, V
IN
= V
IH
or V
IL
, I
I/O
= 0 mA,
Duty 100 %
Min.
cycle
LC35256FM, FT
Parameter
Symbol
-55U
-70U
Unit
min
max
min
max
Write cycle time
t
WC
55
70
ns
Address setup time
t
AS
0
0
ns
Write pulse width
t
WP
40
50
ns
CE setup time
t
CW
50
60
ns
Write recovery time
t
WR
0
0
ns
CE write recovery time
t
WR1
0
0
ns
Data setup time
t
DS
25
30
ns
Data hold time
t
DH
0
0
ns
CE data hold time
t
DH1
0
0
ns
WE output enable time
t
WOE
5
5
ns
WE output disable time
t
WOD
20
30
ns
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