December 2004
®
AS7C25512PFS32A
AS7C25512PFS36A
2.5V 512K
×
32/36 pipelined burst synchronous SRAM
Features
•
•
•
•
•
•
•
•
•
Organization: 524,288 words × 32 or 36 bits
Fast clock speeds to 166 MHz
Fast clock to data access: 3.5/3.8 ns
Fast OE access time: 3.5/3.8 ns
Fully synchronous register-to-register operation
Single-cycle deselect
Asynchronous output enable control
Available in 100-pin TQFP package
Individual byte write and global write
•
•
•
•
•
Multiple chip enables for easy expansion
2.5V core power supply
Linear or interleaved burst control
Snooze mode for reduced power-standby
Common data inputs and data outputs
Logic block diagram
LBO
CLK
ADV
ADSC
ADSP
A[18:0]
19
CLK
CE
CLR
D
CE
Address
register
CLK
D
Q0
Burst logic
Q1
19
Q
17
19
512K × 32/36
Memory
array
GWE
BWE
BW
d
DQ
d
Q
Byte write
registers
CLK
D
DQ
c
Q
Byte write
registers
CLK
DQ
b
Q
Byte write
registers
CLK
D
DQ
a
Q
Byte write
registers
CLK
D
Enable
CE
register
CLK
Power
down
D
Enable
Q
delay
register
CLK
Q
D
36/32
36/32
BW
c
BW
b
BW
a
CE0
CE1
CE2
4
OE
Output
registers
CLK
Input
registers
CLK
ZZ
OE
36/32
DQ[a:d]
Selection guide
Minimum cycle time
Maximum clock frequency
Maximum clock access time
Maximum operating current
Maximum standby current
Maximum CMOS standby current (DC)
-166
6
166
3.5
290
85
40
-133
7.5
133
3.8
270
75
40
Units
ns
MHz
ns
mA
mA
mA
12/23/04, v. 2.2
Alliance Semiconductor
1 of 19
Copyright © Alliance Semiconductor. All rights reserved.
AS7C25512PFS32A
AS7C25512PFS36A
®
16 Mb 2.5V Synchronous SRAM products list
1,2
Org
1MX18
512KX32
512KX36
1MX18
512KX32
512KX36
1MX18
512KX32
512KX36
1MX18
512KX32
512KX36
1MX18
512KX32
512KX36
Part Number
AS7C251MPFS18A
AS7C25512PFS32A
AS7C25512PFS36A
AS7C251MPFD18A
AS7C25512PFD32A
AS7C25512PFD36A
AS7C251MFT18A
AS7C25512FT32A
AS7C25512FT36A
AS7C251MNTD18A
AS7C25512NTD32A
AS7C25512NTD36A
AS7C251MNTF18A
AS7C25512NTF32A
AS7C25512NTF36A
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
166/133 MHz
166/133 MHz
166/133 MHz
166/133 MHz
166/133 MHz
166/133 MHz
7.5/8.5/10 ns
7.5/8.5/10 ns
7.5/8.5/10 ns
166/133 MHz
166/133 MHz
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 = 2.5V + 0.125V
2 I/O Supply Voltage: VDDQ = 2.5V + 0.125V
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
1NTD: 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.
12/23/04, v. 2.2
Alliance Semiconductor
2 of 19
AS7C25512PFS32A
AS7C25512PFS36A
®
Pin assignment
100-pin TQFP - top view
A
A
CE0
CE1
BWd
BWc
BWb
BWa
CE2
V
DD
V
SS
CLK
GWE
BWE
OE
ADSC
ADSP
ADV
A
A
NC/DQPc
DQc0
DQc1
V
DDQ
V
SSQ
DQc2
DQc3
DQc4
DQc5
V
SSQ
V
DDQ
DQc6
DQc7
NC
V
DD
NC
V
SS
DQd0
DQd1
V
DDQ
V
SSQ
DQd2
DQd3
DQd4
DQd5
V
SSQ
V
DDQ
DQd6
DQd7
NC/DQPd
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
100
99
98
97
96
95
94
93
92
91
90
89
88
87
86
85
84
83
82
81
TQFP 14 x 20mm
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
DQPb/NC
DQb7
DQb6
V
DDQ
V
SSQ
DQb5
DQb4
DQb3
DQb2
V
SSQ
V
DDQ
DQb1
DQb0
V
SS
NC
V
DD
ZZ
DQa7
DQa6
V
DDQ
V
SSQ
DQa5
DQa4
DQa3
DQa2
V
SSQ
V
DDQ
DQa1
DQa0
DQPa/NC
Note: For pins 1, 30, 51, and 80, NC applies to the x32 configuration. DQPn applies to the x36 configuration.
12/23/04, v. 2.2
LBO
A
A
A
A
A1
A0
NC
NC
V
SS
V
DD
A
A
A
A
A
A
A
A
A
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
Alliance Semiconductor
3 of 19
AS7C25512PFS32A
AS7C25512PFS36A
®
Functional description
The AS7C25512PFS32A/36A is a high-performance CMOS 16-Mbit synchronous Static Random Access Memory (SRAM) device
organized as 524,288 words x 32/36. It incorporates a two-stage register-register pipeline for highest frequency on any given technology.
Fast cycle times of 6/7.5 ns with clock access times (t
CD
) of 3.5/3.8 ns enable 166 MHz and 133 MHz bus frequencies. Three chip enable
(CE) inputs permit easy memory expansion. Burst operation is initiated in one of two ways: the controller address strobe (ADSC), or the
processor address strobe (ADSP). The burst advance pin (ADV) allows subsequent internally generated burst addresses.
Read cycles are initiated with ADSP (regardless of WE and ADSC) using the new external address clocked into the on-chip address register
when ADSP is sampled low, the chip enables are sampled active, and the output buffer is enabled with OE. In a read operation, the data
accessed by the current address registered in the address registers by the positive edge of CLK are carried to the data-out registers and driven
on the output pins on the next positive edge of CLK. ADV is ignored on the clock edge that samples ADSP asserted, but is sampled on all
subsequent clock edges. Address is incremented internally for the next access of the burst when ADV is sampled low and both address
strobes are high. Burst mode is selectable with the LBO input. With LBO unconnected or driven high, burst operations use an interleaved
count sequence. With LBO driven low, the device uses a linear count sequence.
Write cycles are performed by disabling the output buffers with OE and asserting a write command. A global write enable GWE writes all 32/
36 regardless of the state of individual BW[a:d] inputs. Alternately, when GWE is high, one or more bytes may be written by asserting BWE
and the appropriate individual byte BWn signals.
BWn is ignored on the clock edge that samples ADSP low, but it is sampled on all subsequent clock edges. Output buffers are disabled when
BWn is sampled lOW regardless of OE. Data is clocked into the data input register when BWn is sampled low. Address is incremented
internally to the next burst address if BWn and ADV are sampled low. This device operates in single-cycle deselect feature during read
cycles.
Read or write cycles may also be initiated with ADSC instead of ADSP. The differences between cycles initiated with ADSC and ADSP are
as follows:
• ADSP must be sampled high when ADSC is sampled low to initiate a cycle with ADSC.
• WE signals are sampled on the clock edge that samples ADSC low (and ADSP high).
• Master chip enable CE0 blocks ADSP, but not ADSC.
The AS7C25512PFS32A/36A family operates from a core 2.5V power supply. These devices are available in a 100-pin TQFP package.
TQFP capacitance
Parameter
Input capacitance
I/O capacitance
* Guaranteed not tested
Symbol
C
IN*
C
I/O*
Test conditions
V
IN
= 0V
V
OUT
= 0V
Min
-
-
Max
5
7
Unit
pF
pF
TQFP thermal resistance
Description
Thermal resistance
(junction to ambient)
1
Thermal resistance
(junction to top of case)
1
1 This parameter is sampled
Conditions
Test conditions follow standard test methods
and procedures for measuring thermal
impedance, per EIA/JESD51
1–layer
4–layer
Symbol
θ
JA
θ
JA
θ
JC
Typical
40
22
8
Units
°C/W
°C/W
°C/W
12/23/04, v. 2.2
Alliance Semiconductor
4 of 19
AS7C25512PFS32A
AS7C25512PFS36A
®
Signal descriptions
Pin
CLK
A,A0,A1
DQ[a,b,c,d]
CE0
CE1, CE2
ADSP
ADSC
ADV
GWE
BWE
BW[a,b,c,d]
OE
LBO
ZZ
NC
I/O Properties Description
I
I
I/O
I
I
I
I
I
I
I
I
I
I
I
-
CLOCK
SYNC
SYNC
SYNC
SYNC
SYNC
SYNC
SYNC
SYNC
SYNC
SYNC
ASYNC
STATIC
ASYNC
-
Clock. All inputs except OE, ZZ, and LBO are synchronous to this clock.
Address. Sampled when all chip enables are active and when ADSC or ADSP are asserted.
Data. Driven as output when the chip is enabled and when OE is active.
Master chip enable. Sampled on clock edges when ADSP or ADSC is active. When CE0 is
inactive, ADSP is blocked. Refer to the “Synchronous truth table” for more information.
Synchronous chip enables, active high, and active low, respectively. Sampled on clock
edges when ADSC is active or when CE0 and ADSP are active.
Address strobe processor. Asserted low to load a new address or to enter standby mode.
Address strobe controller. Asserted low to load a new address or to enter standby mode.
Advance. Asserted low to continue burst read/write.
Global write enable. Asserted low to write all 32/36 and 18 bits. When high, BWE and
BW[a:d] control write enable.
Byte write enable. Asserted low with GWE high to enable effect of BW[a:d] inputs.
Write enables. Used to control write of individual bytes when GWE is high and BWE is
low. If any of BW[a:d] is active with GWE high and BWE low, the cycle is a write cycle. If
all BW[a:d] are inactive, the cycle is a read cycle.
Asynchronous output enable. I/O pins are driven when OE is active and chip is in read
mode.
Selects Burst mode. When tied to V
DD
or left floating, device follows interleaved Burst order. When
driven Low, device follows linear Burst order.
This signal is internally pulled High.
Snooze. Places device in low power mode; data is retained. Connect to GND if unused.
No connect
Snooze Mode
SNOOZE MODE is a low current, power-down mode in which the device is deselected and current is reduced to I
SB2
. The duration of
SNOOZE MODE is dictated by the length of time the ZZ is in a High state.
The ZZ pin is an asynchronous, active high input that causes the device to enter SNOOZE MODE.
When the ZZ pin becomes a logic High, I
SB2
is guaranteed after the time t
ZZI
is met. After entering SNOOZE MODE, all inputs except ZZ is
disabled and all outputs go to High-Z. Any operation pending when entering SNOOZE MODE is not guaranteed to successfully complete.
Therefore, SNOOZE MODE (READ or WRITE) must not be initiated until valid pending operations are completed. Similarly, when exiting
SNOOZE MODE during t
PUS
, only a DESELECT or READ cycle should be given while the SRAM is transitioning out of SNOOZE MODE.
12/23/04, v. 2.2
Alliance Semiconductor
5 of 19
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