AS4LC256K16EO
®
3.3V 256K X 16 CMOS DRAM (EDO)
Features
• EDO page mode
• 5V I/O tolerant
• Organization: 262,144 words × 16 bits
• High speed
• 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
- 400 mil, 40-pin SOJ
- 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
- Active: 280 mW max (AS4LC256K16EO-35)
- Standby: 2.8 mW max, CMOS I/O (AS4LC256K16EO-
35)
- 400 mil, 40/44-pin TSOP II
• 3.3V power supply
• Latch-up current > 200 mA
Pin arrangement
Pin designation
Pin(s)
A0 to A8
RAS
Description
TSOP II
SOJ
VCC
I/O0
I/O1
I/O2
I/O3
VCC
I/O4
GND
I/O15
I/O14
I/O13
I/O12
GND
I/O11
I/O10
I/O9
I/O8
1
44
43
42
41
40
39
38
37
36
35
Address inputs
Vcc
I/O0
I/O1
I/O2
I/O3
Vcc
I/O4
I/O5
I/O6
I/O7
NC
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
2
3
Row address strobe
Input/output
4
5
I/O0 to I/O15
OE
6
7
Output enable
I/O5
8
I/O6
9
UCAS
LCAS
Column address strobe, upper byte
Column address strobe, lower byte
Read/write control
Power (3.3V ± 0.3V)
Ground
I/O7
10
NC
NC
NC
NC
13
14
15
16
17
18
19
20
21
22
32
31
30
29
28
27
26
25
24
23
WE
WE
RAS
NC
A0
A1
A2
A3
Vcc
LCAS
UCAS
OE
WE
RAS
NC
A0
VCC
A6
A5
A4
GND
A8
GND
A7
A1
A6
A2
A5
A3
A4
VCC
GND
Selection guide
Symbol AS4LC256K16EO-35 AS4LC256K16EO-45 AS4LC256K16EO-60 Unit
Maximum RAS access time
tRAC
tCAA
tCAC
tOEA
tRC
35
17
7
45
20
10
10
80
17
60
200
60
25
ns
ns
Maximum column address access time
Maximum CAS access time
10
ns
Maximum output enable (OE) access time
Minimum read or write cycle time
Minimum EDO page mode cycle time
Maximum operating current
7
10
ns
50
15
70
200
100
30
ns
tPC
ns
ICC1
ICC2
50
mA
µA
Maximum CMOS standby current
200
4/11/01; V.1.1
Alliance Semiconductor
P. 1 of 25
Copyright © Alliance Semiconductor. All rights reserved.