AS7C33256PFD16A
AS7C33256PFD18A
March 2002
®
3.3V 256K × 16/18 pipeline burst synchronous SRAM
Features
• Byte write enables
• Multiple chip enables for easy expansion
• 3.3V core power supply
• Organization: 262,144 words × 16 or 18 bits
• Fast clock speeds to 200 MHz in LVTTL/LVCMOS
• Fast clock to data access: 3.0/3.1/3.5/4.0/5.0 ns
• Fast OE access time: 3.0/3.1/3.5/4.0/5.0 ns
• Fully synchronous register-to-register operation
• “Flow-through” mode
• Dual-cycle deselect
- Single-cycle deselect also available (AS7C33256PFS16A/
AS7C33256PFS18A)
• 2.5V or 3.3V I/O operation with separate V
DDQ
• 30 mW typical standby power in power down mode
• NTD™<Superscript>1 pipeline architecture avail-
able
• (AS7C33256NTD16A/AS7C33256NTD18A)
1
®
1. Pentium is a registered trademark of Intel Corporation. NTD™ is a
• Pentium® compatible architecture and timing
• Asynchronous output enable control
• Economical 100-pin TQFP package
trademark of Alliance Semiconductor Corporation. All trademarks men-
tioned in this document are the property of their respective owners.
Pin arrangement
Logic block diagram
LBO
CLK
ADV
CLK
CS
Burst logic
18 16
256K × 16/18
Memory
ADSC
ADSP
A17
NC
NC
V
SSQ
NC
DQpa/NC
DQa
DQa
NC
NC
NC
1
80
79
78
77
76
75
74
73
72
71
70
69
68
67
66
65
64
63
62
61
60
59
58
57
56
55
54
53
52
51
CLR
2
3
18
18
AddresQs
register
D
array
A[17:0]
V
4
DDQ
DDQ
V
V
5
CS
SSQ
NC
6
CLK
NC
7
DQb
DQb
8
16/18
16/18
9
V
V
V
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
SSQ
DDQ
SSQ
V
GWE
BW
D
Q
DDQ
DQb
DQb
FT
DQb
DQa
DQa
VSS
NC
b
Byte Write
registers
TQFP 14 × 20mm
BWE
CLK
V
DD
D
Q
V
ZZ
NC
DD
DQa
V
DQb
DQb
2
SS
BW
Byte Write
registers
a
DQa
DQa
CLK
V
V
V
DDQ
SSQ
DDQ
CE0
CE1
CE2
OE
V
SSQ
D EnableQ
register
Input
DQa
DQa
NC
DQb
Output
registers
DQb
DQpb/NC
NC
registers
CE
CLK
CLK
CLK
NC
V
V
V
SSQ
DDQ
SSQ
D EnableQ
delay
V
DDQ
Power
down
NC
NC
NC
NC
NC
NC
ZZ
register
CLK
OE
16/18
DQ [a,b]
FT
Note: pins 24, 74 are NC for ×16.
Selection guide
–200
5
–183
5.4
–166
6
–133
7.5
133
4
–100
10
Units
Minimum cycle time
ns
MHz
ns
Maximum pipelined clock frequency
Maximum pipelined clock access time
Maximum operating current
200
3
183
3.1
166
3.5
475
130
30
100
5
570
160
30
540
140
30
425
100
30
325
90
mA
mA
mA
Maximum standby current
Maximum CMOS standby current (DC)
30
3/8/02; v.1.6
Alliance Semiconductor
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