AS4C256K16FO
®
5V 256K X 16 CMOS DRAM (Fast Page Mode)
Features
• Organization: 262,144 words × 16 bits
• High speed
- 25/30/35/50 ns RAS access time
- 12/16/18/25 ns column address access time
- 7/10/10/10 ns CAS access time
• Low power consumption
- Active: 770 mW max (ASAS4C256K16FO-50)
- Standby: 5.5 mW max, CMOS I/O
• Fast page mode
• AS4C256K16FO-50 timings
are also valid for
AS4C256K16FO-60.
• Refresh
- 512 refresh cycles, 8 ms refresh interval
- RAS-only or CAS-before-RAS refresh or self-refresh
- Self-refresh option is available for new generation
device only. Contact Alliance for more information.
• Read-modify-write
• TTL-compatible, three-state I/O
• JEDEC standard packages
- 400 mil, 40-pin SOJ
- 400 mil, 40/44-pin TSOP II
• Single 5V power supply/built-in V
bb
generator
• Latch-up current > 200 mA
Pin arrangement
SOJ
V
CC
I/O0
I/O1
I/O2
I/O3
V
CC
I/O4
I/O5
I/O6
I/O7
NC
NC
WE
RAS
NC
A0
A1
A2
A3
V
CC
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
40
39
38
37
36
35
34
33
32
31
30
29
28
27
26
25
24
23
22
21
GND
I/O15
I/O14
I/O13
I/O12
GND
I/O11
I/O10
I/O9
I/O8
NC
LCAS
UCAS
OE
A8
A7
A6
A5
A4
GND
V
CC
I/O0
I/O1
I/O2
I/O3
V
CC
I/O4
I/O5
I/O6
I/O7
NC
NC
WE
RAS
NC
A0
A1
A2
A3
V
CC
TSOP II
44
1
43
2
42
3
41
4
40
5
39
6
38
7
37
8
36
9
35
10
ASC256K16FO
13
14
15
16
17
18
19
20
21
22
32
31
30
29
28
27
26
25
24
23
V
SS
I/O15
I/O14
I/O13
I/O12
V
SS
I/O11
I/O10
I/O9
I/O8
NC
LCAS
UCAS
OE
A8
A7
A6
A5
A4
V
SS
Pin designation
Pin(s)
A0 to A8
RAS
I/O0 to I/O15
OE
UCAS
LCAS
WE
V
CC
GND
Description
Address inputs
Row address strobe
Input/output
Output enable
Column address strobe, upper byte
Column address strobe, lower byte
Read/write control
Power (+5V
±
10%)
Ground
Selection guide
Symbol
Maximum RAS access time
Maximum column address
access time
Maximum CAS access time
Maximum output enable (OE)
access time
Minimum read or write cycle
time
Minimum EDO page mode
cycle time
Maximum operating current
Maximum CMOS standby
current
4/11/01; V.0.9.1
ASC256K16FO
–25
25
12
7
7
40
12
200
2.0
–30
30
16
10
10
65
12
180
2.0
–35
35
18
10
10
70
14
160
2.0
–50
50
25
10
10
85
25
140
2.0
Unit
ns
ns
ns
ns
ns
ns
mA
mA
t
RAC
t
CAA
t
CAC
t
OEA
t
RC
t
PC
I
CC1
I
CC2
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