December 2002
Advance Information
®
AS7C251MPFS18A
2.5V 1M x 18 pipelined burst synchronous SRAM
Features
•
•
•
•
•
•
•
Organization: 1,048,576 x18 bits
Fast clock speeds to 250MHz in LVTTL/LVCMOS
Fast clock to data access: 2.6/2.8/3/3.4 ns
Fast OE access time: 2.6/2.8/3/3.4 ns
Fully synchronous register-to-register operation
Single register flow-through mode
Single-cycle deselect
•
•
•
•
•
•
Asynchronous output enable control
Available 100-pin TQFP and 165-ball BGA packages
Byte write enables
Multiple chip enables for easy expansion
2.5V core power supply
NTD™ pipelined architecture available (AS7C251MNTD18A,
AS7C25512NTD32A/ AS7C25512NTD36A)
Logic block diagram
LBO
CLK
ADV
ADSC
ADSP
A[19:0]
CLK
CS
CLR
Burst logic
Q
20
D
CS
CLK
20
18 20
Address
register
1M
[
18
Memory
array
18
GWE
BW
b
BWE
BW
a
CE0
CE1
CE2
D
DQb
Q
18
Byte Write
registers
Byte Write
registers
CLK
D
CLK
D
DQa
Q
2
OE
Enable
Q
register
CE
CLK
ZZ
Output
registers
CLK
Input
registers
CLK
Power
down
D
Enable
Q
delay
register
CLK
OE
18
FT DQ[a,b]
Selection guide
Minimum cycle time
Maximum clock frequency
Maximum pipelined clock access time
Maximum operating current
Maximum standby current
Maximum CMOS standby current (DC)
-250
4
250
2.6
425
110
70
-225
4.4
225
2.8
400
110
70
-200
5
200
3.0
370
110
70
-166
6
166
3.4
340
90
70
Units
ns
MHz
ns
mA
mA
mA
12/2/02, v. 0.9.2 Advance Info
Alliance Semiconductor
1 of 21
Copyright © Alliance Semiconductor. All rights reserved.