AS4LC256K16EO
®
3.3V 256K X 16 CMOS DRAM (EDO)
Features
• Organization: 262,144 words × 16 bits
• High speed
- 45/60 ns RAS access time
- 10/12/15/20 ns column address access time
- 7/10/10 ns CAS access time
• Low power consumption
• EDO page mode
• 5V I/O tolerant
• 512 refresh cycles, 8 ms refresh interval
- RAS-only or CAS-before-RAS refresh or self refresh
• Read-modify-write
• LVTTL-compatible, three-state I/O
• JEDEC standard packages
- Active: 280 mW max (AS4LC256K16EO-35)
- Standby: 2.8 mW max, CMOS I/O (AS4LC256K16EO-
35)
- 400 mil, 40-pin SOJ
- 400 mil, 40/44-pin TSOP II
• 3.3V power supply
• Latch-up current > 200 mA
Pin arrangement
SOJ
Vcc
I/O0
I/O1
I/O2
I/O3
Vcc
I/O4
I/O5
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
Pin designation
TSOP II
V
CC
I/O0
I/O1
I/O2
I/O3
V
CC
I/O4
I/O5
I/O6
I/O7
NC
NC
WE
RAS
Pin(s)
44
43
42
41
40
39
38
37
36
35
32
31
30
29
28
27
26
25
24
23
GND
I/O15
I/O14
I/O13
I/O12
GND
I/O11
I/O10
I/O9
I/O8
NC
LCAS
UCAS
OE
Description
Address inputs
Row address strobe
Input/output
Output enable
Column address strobe, upper byte
Column address strobe, lower byte
Read/write control
Power (3.3V
±
0.3V)
Ground
AS4LC256K16EO
AS4LC256K16EO
I/O6
I/O7
NC
NC
WE
RAS
NC
A0
A1
A2
I/O9
I/O8
NC
LCAS
UCAS
OE
A8
A7
A6
A5
1
2
3
4
5
6
7
8
9
10
13
14
15
16
17
18
19
20
21
22
A0 to A8
RAS
I/O0 to I/O15
OE
UCAS
LCAS
WE
V
CC
GND
A3
Vcc
A4
GND
NC
A0
A1
A2
A3
V
CC
A8
A7
A6
A5
A4
GND
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
t
RAC
t
CAA
t
CAC
t
OEA
t
RC
t
PC
I
CC1
I
CC2
AS4LC256K16EO-35
35
17
7
7
50
15
70
200
AS4LC256K16EO-45
45
20
10
10
80
17
60
200
AS4LC256K16EO-60
60
25
10
10
100
30
50
200
Unit
ns
ns
ns
ns
ns
ns
mA
µA
4/11/01; V.1.1
Alliance Semiconductor
P. 1 of 25
Copyright © Alliance Semiconductor. All rights reserved.
ALSC [ ALLIANCE SEMICONDUCTOR CORPORATION ]
