November 2004
®
AS7C331MNTF32A
AS7C331MNTF36A
3.3V 1M × 32/36 Flowthrough SRAM with NTD
TM
Features
•
•
•
•
•
•
•
•
•
Organization: 1,048,576 words × 32 or 36 bits
NTD
™
architecture for efficient bus operation
Fast clock to data access: 7.5/8.5/10 ns
Fast OE access time: 3.5/4.0 ns
Fully synchronous operation
Flow-through mode
Asynchronous output enable control
Available in 100-pin TQFP and 165-ball BGA package
Byte write enables
•
•
•
•
•
•
•
•
Clock enable for operation hold
Multiple chip enables for easy expansion
3.3V core power supply
2.5V or 3.3V I/O operation with separate V
DDQ
Self-timed write cycles
Interleaved or linear burst modes
Snooze mode for standby operation
Boundary Scan using IEEE 1149.1 JTAG function is avail-
able in 165 Ball BGA Package only.
Logic block diagram
A[19:0]
20
D
Address
register
Burst logic
Q
20
CLK
CE0
CE1
CE2
R/W
BWa
BWb
BWc
BWd
ADV / LD
LBO
ZZ
D
Q
20
Write delay
addr. registers
CLK
Control
logic
CLK
Write Buffer
CLK
1M x 32/36
SRAM
Array
DQ[a,b,c,d]
32/36
D
Data
Q
Input
Register
CLK
32/36
32/36
32/36
32/36
CLK
CEN
OE
Output
Buffer
32/36
OE
DQ[a,b,c,d]
Selection guide
-75
Minimum cycle time
Maximum clock access time
Maximum operating current
Maximum standby current
Maximum CMOS standby current (DC)
8.5
7.5
325
140
90
-85
10
8.5
300
130
90
-10
12
10
275
130
90
Units
ns
ns
mA
mA
mA
11/25/04, v 1.1
Alliance Semiconductor
P. 1 of 26
Copyright © Alliance Semiconductor. All rights reserved.
AS7C331MNTF32A/36A
®
32 Mb Synchronous SRAM products list
1,2
Org
2MX18
1MX32
1MX36
2MX18
1MX32
1MX36
2MX18
1MX32
1MX36
2MX18
1MX32
1MX36
2MX18
1MX32
1MX36
Part Number
AS7C332MPFS18A
AS7C331MPFS32A
AS7C331MPFS36A
AS7C332MPFD18A
AS7C331MPFD32A
AS7C331MPFD36A
AS7C332MFT18A
AS7C331MFT32A
AS7C331MFT36A
AS7C332MNTD18A
AS7C331MNTD32A
AS7C331MNTD36A
AS7C332MNTF18A
AS7C331MNTF32A
AS7C331MNTF36A
Mode
PL-SCD
PL-SCD
PL-SCD
PL-DCD
PL-DCD
PL-DCD
FT
FT
FT
NTD-PL
NTD-PL
NTD-PL
NTD-FT
NTD-FT
NTD-FT
Speed
200/166/133 MHz
200/166/133 MHz
200/166/133 MHz
200/166/133 MHz
200/166/133 MHz
200/166/133 MHz
7.5/8.5/10 ns
7.5/8.5/10 ns
7.5/8.5/10 ns
200/166/133 MHz
200/166/133 MHz
200/166/133 MHz
7.5/8.5/10 ns
7.5/8.5/10 ns
7.5/8.5/10 ns
1 Core Power Supply: VDD = 3.3V + 0.165V
2 I/O Supply Voltage: VDDQ = 3.3V + 0.165V for 3.3V I/O
VDDQ = 2.5V + 0.125V for 2.5V I/O
PL-SCD
PL-DCD
FT
NTD
1
-PL
NTD-FT
:
:
:
:
:
Pipelined Burst Synchronous SRAM - Single Cycle Deselect
Pipelined Burst Synchronous SRAM - Double Cycle Deselect
Flow-through Burst Synchronous SRAM
Pipelined Burst Synchronous SRAM with NTD
TM
Flow-through Burst Synchronous SRAM with NTD
TM
1. NTD: No Turnaround Delay. NTD
TM
is a trademark of Alliance Semiconductor Corporation. All trademarks mentioned in this document are the property
of their respective owners.
11/25/04, v 1.1
Alliance Semiconductor
P. 2 of 26
AS7C331MNTF32A/36A
®
Functional Description
The AS7C331MNTF32A/36A family is a high performance CMOS 32 Mbit synchronous Static Random Access Memory
(SRAM) organized as 1,048,576 words × 32 or 36 bits and incorporates a LATE Write.
This variation of the 32Mb+ synchronous SRAM uses the No Turnaround Delay (NTD
™
) architecture, featuring an enhanced
write operation that improves bandwidth over flowthrough burst devices. In a normal flowthrough burst device, the write data,
command, and address are all applied to the device on the same clock edge. If a read command follows this write command,
the system must wait for one dead cycle for valid data to become available. This dead cycle can significantly reduce overall
bandwidth for applications requiring random access or read-modify-write operations.
NTD
™
devices use the memory bus more efficiently by introducing a write latency which matches the one-cycle flow-
through read latency. Write data is applied one cycle after the write command and address, allowing the read pipeline to clear.
With NTD
™
, write and read operations can be used in any order without producing dead bus cycles.
Assert R/W low to perform write cycles. Byte write enable controls write access to specific bytes, or can be tied low for full 36
bit writes. Write enable signals, along with the write address, are registered on a rising edge of the clock. Write data is applied
to the device one clock cycle later. Unlike some asynchronous SRAMs, output enable OE does not need to be toggled for write
operations; it can be tied low for normal operations. Outputs go to a high impedance state when the device is de-selected by
any of the three chip enable inputs.
Use the ADV (burst advance) input to perform burst read, write and deselect operations. When ADV is high, external addresses, chip
select, R/W pins are ignored, and internal address counters increment in the count sequence specified by the LBO control. Any
device operations, including burst, can be stalled using the CEN=1, the clock enable input.
The AS7C331MNTF32A/36A operates with a 3.3V ± 5% power supply for the device core (V
DD
). DQ circuits use a separate
power supply (V
DDQ
) that operates across 3.3V or 2.5V ranges. These devices are available in a 100-pin TQFP package and
165 Ball BGA package.
TQFP and BGA Capacitance
Parameter
Input capacitance
I/O capacitance
*Guranteed not tested
Symbol
C
IN*
C
I/O*
Test conditions
V
in
= 0V
V
in
= V
out
= 0V
Min
-
-
Max
5
7
Unit
pF
pF
TQFP and BGA thermal resistance
Description
Thermal resistance
(junction to ambient)
1
Thermal resistance
(junction to top of case)
1
1 This parameter is sampled
Conditions
1–layer
Test conditions follow standard test methods and
procedures for measuring thermal impedance,
per EIA/JESD51
4–layer
Symbol
θ
JA
θ
JA
θ
JC
Typical
40
22
8
Units
°C/W
°C/W
°C/W
11/25/04, v 1.1
Alliance Semiconductor
P. 5 of 26
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