April 2004
AS7C251MNTD32A
AS7C251MNTD36A
®
2.5V 1M × 32/36 SRAM with NTDTM
Features
• Common data inputs and data outputs
• Organization: 1,048,576 words × 32 or 36 bits
• NTD™1 architecture for efficient bus operation
• Fast clock speeds to 200 MHz in LVTTL/LVCMOS
• Fast clock to data access: 3.1/3.4/3.8 ns
• Fast OE access time: 3.1/3.4/3.8 ns
• Asynchronous output enable control
• Available in 100-pin TQFP and 165-ball BGA packages
• Byte write enables
• Clock enable for operation hold
• Multiple chip enables for easy expansion
• 2.5V core power supply
• Fully synchronous operation
• Flow-through or pipelined mode
• Self-timed write cycles
• Interleaved or linear burst modes
• Snooze mode for standby operation
• Boundary scan using IEEE 1149.1 JTAG function
1. NTD™ is a trademark of Alliance Semiconductor Corporation. All trade-
marks mentioned in this document are the property of their respective owners.
Logic block diagram
20
20
Q
A[19:0]
D
Address
register
Burst logic
CLK
D
Q
CE0
CE1
CE2
Write delay
addr. registers
20
CLK
R/W
BWa
Control
logic
CLK
BWb
BWc
BWd
ADV / LD
FT
1M x 32/36
SRAM
LBO
ZZ
CLK
Array
32/36
32/36
DQ[a,b,c,d]
Data
Input
Register
D
Q
32/36
32/36
CLK
32/36
CLK
CEN
CLK
Output
Register
OE
32/36
OE
DQ[a,b,c,d]
Selection guide
-200
5
-167
6
-133
7.5
Units
ns
Minimum cycle time
Maximum pipelined clock frequency
Maximum pipelined clock access time
Maximum operating current
200
3.1
400
120
70
167
3.4
350
110
70
133
3.8
MHz
ns
325
100
70
mA
mA
mA
Maximum standby current
Maximum CMOS standby current (DC)
4/26/04, V 1.0
Alliance Semiconductor
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