ALSC AS7C256A

September 2004
AS7C256A
®
5V 32K X 8 CMOS SRAM (Common I/O)
Features
• TTL-compatible, three-state I/O
• 28-pin JEDEC standard packages
- 300 mil SOJ
- 8 × 13.4 mm TSOP 1
• ESD protection ≥ 2000 volts
• Latch-up current ≥ 200 mA
• 2.0V Data retention
•
•
•
•
Pin compatible with AS7C256
Industrial and commercial temperature options
Organization: 32,768 words × 8 bits
High speed
- 10/12/15/20 ns address access time
- 5, 6, 7, 8 ns output enable access time
• Very low power consumption: ACTIVE
- 412.5 mW max @ 10 ns
• Very low power consumption: STANDBY
- 11 mW max CMOS I/O
• Easy memory expansion with CE and OE inputs
Logic block diagram
Pin arrangement
28-pin TSOP 1 (8×13.4 mm)
VCC
28-pin SOJ (300 mil)
Input buffer
256 X 128 X 8
Array
(262,144)
Sense amp
I/O7
Row decoder
A0
A1
A2
A3
A4
A5
A6
A7
I/O0
Column decoder
OE
A11
A9
A8
A13
WE
VCC
A14
A12
A7
A6
A5
A4
A3
1
2
3
4
5
6
7
8
9
10
11
12
13
14
28
27
26
25
24
23
22
21
20
19
18
17
16
15
AS7C256A
WE
Control
A10
CE
I/O7
I/O6
I/O5
I/O4
I/O3
GND
I/O2
I/O1
I/O0
A0
A1
A2
A14
A12
A7
A6
A5
A4
A3
A2
A1
A0
I/O0
I/O1
I/O2
GND
1
2
3
4
5
6
7
8
9
10
11
12
13
14
AS7C256A
GND
28
27
26
25
24
23
22
21
20
19
18
17
16
15
VCC
WE
A13
A8
A9
A11
OE
A10
CE
I/O7
I/O6
I/O5
I/O4
I/O3
OE
circuit
CE
A A A A A A A
8 9 10 11 12 13 14
Selection guide
-10
-12
-15
-20
Unit
Maximum address access time
10
12
15
20
ns
Maximum output enable access time
5
6
7
8
ns
Maximum operating current
75
70
65
60
mA
Maximum CMOS standby current
2
2
2
2
mA
9/24/04; v.1.2
Alliance Semiconductor
P. 1 of 9
Copyright © Alliance Semiconductor. All rights reserved.
AS7C256A
®
Functional description
The AS7C256A is a 5.0V high-performance CMOS 262,144-bit Static Random-Access Memory (SRAM) device organized
as 32,768 words × 8 bits. It is designed for memory applications requiring fast data access at low voltage, including
PentiumTM, PowerPCTM, and portable computing. Alliance’s advanced circuit design and process techniques permit 5.0V
operation without sacrificing performance or operating margins.
The device enters standby mode when CE is high. CMOS standby mode consumes ≤11 mW. Normal operation offers 75%
power reduction after initial access, resulting in significant power savings during CPU idle, suspend, and stretch mode.
Equal address access and cycle times (tAA, tRC, tWC) of 10/12/15/20 ns with output enable access times (tOE) of 5, 6, 7, 8 ns
are ideal for high-performance applications. The chip enable (CE) input permits easy memory expansion with multiple-bank
memory organizations.
A write cycle is accomplished by asserting chip enable (CE) and write enable (WE) LOW. Data on the input pins I/O0-I/O7
is written on the rising edge of WE (write cycle 1) or CE (write cycle 2). To avoid bus contention, external devices should
drive I/O pins only after outputs have been disabled with output enable (OE) or write enable (WE).
A read cycle is accomplished by asserting chip enable (CE) and output enable (OE) LOW, with write enable (WE) high. The
chip drives I/O pins with the data word referenced by the input address. When chip enable or output enable is high, or write
enable is low, output drivers stay in high-impedance mode.
All chip inputs and outputs are TTL-compatible. Operation is from a single 5.0 ±0.5V supply. The AS7C256A is packaged
in high volume industry standard packages.
Absolute maximum ratings
Parameter
Symbol
Min
Max
Unit
Voltage on VCC relative to GND
Vt1
–0.5
+7.0
V
Voltage on any pin relative to GND
Vt2
–0.5
VCC + 0.5
V
Power dissipation
PD
–
1.0
Storage temperature (plastic)
Tstg
–65
W
+150
o
C
Ambient temperature with VCC applied
Tbias
–55
+125
oC
DC current into outputs (low)
IOUT
–
20
mA
Stresses greater than those listed under Absolute Maximum Ratings may cause permanent damage to the device. This is a stress rating only and functional
operation of the device at these or any other conditions outside those indicated in the operational sections of this specification is not implied. Exposure to
absolute maximum rating conditions for extended periods may affect reliability.
Truth table
CE
WE
OE
Data
Mode
H
X
X
High Z
Standby (ISB, ISB1)
L
H
H
High Z
Output disable (ICC)
L
H
L
DOUT
Read (ICC)
L
L
X
DIN
Write (ICC)
Key: X = Don’t care, L = Low, H = High
9/24/04; v.1.2
Alliance Semiconductor
P. 2 of 9
AS7C256A
®
Recommended operating conditions
Parameter
Symbol
Min
Typical
Max
Unit
Supply voltage
VCC
4.5
5.0
5.5
V
Input voltage
VIH**
VIL*
2.2
–
VCC+0.5
V
-0.5
–
0.8
V
Ambient operating temperature
commercial
TA
0
–
70
oC
industrial
TA
–40
–
85
o
C
*
VIL min = –1.0V for pulse width less than 5ns.
**
VIH max = VCC + 2.0V for pulse width less than 5ns.
DC operating characteristics (over the operating range)1
-10
Parameter
Sym
Input leakage
current
|ILI|
Test conditions
-12
-15
-20
Min Max Min Max Min Max Min Max Unit Notes
VCC = Max,
Vin = GND to VCC
–
1
–
1
–
1
–
1
µA
Output leakage
V = Max,
|ILO| CC
current
VOUT = GND to VCC
–
1
–
1
–
1
–
1
µA
Operating
power supply
current
Standby power
supply current
Output voltage
ICC
VCC = Max, CE < VIL
f = fMax, IOUT = 0mA
–
75
-
70
–
65
–
60
mA
ISB
VCC = Max, CE > VIH
f = fMax
–
45
–
45
–
40
–
40
mA
VCC = Max, CE > VCC–0.2V
ISB1 VIN < 0.2V or
VIN > VCC–0.2V, f = 0
–
2.0
–
2.0
–
2.0
–
2.0
mA
VOL IOL = 8 mA, VCC = Min
–
0.4
–
0.4
–
0.4
–
0.4
V
4
VOH IOH = –4 mA, VCC = Min
2.4
–
2.4
–
2.4
–
2.4
–
V
4
Capacitance (f = 1MHz, Ta = room temperature, VCC = NOMINAL)4
Parameter
Symbol
Signals
Test conditions
Max
Unit
Input capacitance
CIN
A, CE, WE, OE
Vin = 0V
5
pF
I/O capacitance
CI/O
I/O
Vin = Vout = 0V
7
pF
9/24/04; v.1.2
Alliance Semiconductor
P. 3 of 9
AS7C256A
®
Read cycle (over the operating range)2,8
-10
Parameter
Symbol Min
-12
-15
-20
Max
Min
Max
Min
Max
Min
Max
Unit
Notes
Read cycle time
tRC
10
–
12
–
15
–
20
–
ns
Address access time
tAA
–
10
–
12
–
15
–
20
ns
2
Chip enable (CE) access time
tACE
–
10
–
12
–
15
–
20
ns
2
Output enable (OE) access time
tOE
–
5
–
6
–
7
–
8
ns
Output hold from address change
tOH
3
–
3
–
3
–
3
–
ns
4
CE LOW to output in low Z
tCLZ
3
–
3
–
3
–
3
–
ns
3,4
CE HIGH to output in high Z
tCHZ
–
3
–
3
–
4
–
5
ns
3,4
OE LOW to output in low Z
tOLZ
0
–
0
–
0
–
0
–
ns
3,4
OE HIGH to output in high Z
tOHZ
–
3
–
3
–
4
–
5
ns
3,4
Power up time
tPU
0
–
0
–
0
–
0
–
ns
3,4
Power down time
tPD
–
10
–
12
–
15
–
20
ns
3,4
Key to switching waveforms
Rising input
Falling input
Undefined output/don’t care
Read waveform 1 (address controlled)2,5,6,8
tRC
Address
tOH
tAA
Dout
Data valid
Read waveform 2 (CE controlled)2,5,7,8
tRC1
CE
tOE
OE
tOLZ
tOHZ
tCHZ
tACE
Dout
Data valid
tCLZ
Supply
current
9/24/04; v.1.2
tPU
tPD
50%
Alliance Semiconductor
ICC
ISB
50%
P. 4 of 9
AS7C256A
®
Write cycle (over the operating range)9
-10
Parameter
-12
-15
-20
Symbol
Min
Max
Min
Max
Min
Max
Min
Max
Unit
Write cycle time
tWC
10
–
12
–
15
–
20
–
ns
Chip enable to write end
tCW
8
–
8
–
10
–
12
–
ns
Address setup to write end
tAW
8
–
8
–
10
–
12
–
ns
Address setup time
tAS
0
–
0
–
0
–
0
–
ns
Write pulse width
tWP
7
–
8
–
9
–
12
–
ns
Write recovery time
tWR
0
–
0
–
0
–
0
–
ns
Address hold from end of write
tAH
0
–
0
–
0
–
0
–
ns
Data valid to write end
tDW
5
–
6
–
8
–
10
–
ns
Data hold time
tDH
0
–
0
–
0
–
0
–
ns
3,4
Write enable to output in high Z
tWZ
–
5
–
6
–
7
–
8
ns
3,4
Output active from write end
tOW
3
–
3
–
3
–
3
–
ns
3,4
Write waveform 1 (WE controlled)9
tWC
tAW
tAH
Address
tWR
tWP
WE
tAS
tDW
Din
tDH
Data valid
tWZ
tOW
Dout
Write waveform 2 (CE controlled)9
tAW
tWC
tAH
Address
tAS
tWR
tCW
CE
WE
tDW
Din
9/24/04; v.1.2
tDH
Data valid
Alliance Semiconductor
P. 5 of 9
Notes
AS7C256A
®
AC test conditions
-
Output load: see Figure B
Input pulse level: GND to VCC See Figure A.
Input rise and fall times: 2 ns. See Figure A.
Input and output timing reference levels: 1.5V.
+5.0V
VCC
GND
90%
10%
90%
2 ns
10%
Figure A: Input pulse
Dout
255Ω
Thevenin equivalent
480Ω
C10
Dout
168Ω
+1.72V
GND
Figure B: Output load
Notes
1
2
3
4
5
6
7
8
9
10
During VCC power-up, a pull-up resistor to VCC on CE is required to meet ISB specification.
For test conditions, see AC Test Conditions, Figures A, B.
These parameters are specified with CL = 5pF, as in Figures B. Transition is measured ±500mV from steady-state voltage.
This parameter is guaranteed, but not tested.
WE is High for read cycle.
CE and OE are Low for read cycle.
Address valid prior to or coincident with CE transition Low.
All read cycle timings are referenced from the last valid address to the first transitioning address.
All write cycle timings are referenced from the last valid address to the first transitioning address.
C=30pF, except on High Z and Low Z parameters, where C=5pF.
9/24/04; v.1.2
Alliance Semiconductor
P. 6 of 9
AS7C256A
®
Package diagrams
28-pin SOJ
D
e
28-pin SOJ
Min
Max
in inches
B
A
A1
E1 E2
Seating
Plane
b
Pin 1
c
A2
E
28-pin TSOP1
b
A
A1
A2
B
b
c
D
E
E1
E2
e
e
28-pin TSOP1
8×13.4 mm
Min
Max
c
A2
L
D Hd
α
E
9/24/04; v.1.2
0.128
0.148
0.026
0.095
0.105
0.026
0.032
0.016
0.020
0.007
0.010
0.720
0.730
0.255
0.275
0.295
0.305
0.330
0.340
0.050 BSC
Alliance Semiconductor
A
A1
A
A1
A2
b
c
D
e
E
Hd
L
α
1.00
1.20
0.05
0.15
0.91
1.05
0.17
0.27
0.10
0.20
11.70
11.90
0.55 nominal
7.90
8.10
13.20
13.60
0.50
0.70
0°
5°
P. 7 of 9
AS7C256A
®
Ordering information
Temperature
10 ns
12 ns
15 ns
20 ns
Commercial
AS7C256A-10JC
AS7C256A-12JC
AS7C256A-15JC
AS7C256A-20JC
Industrial
AS7C256A-10JI
AS7C256A-12JI
AS7C256A-15JI
AS7C256A-20JI
Commercial
AS7C256A-10TC
AS7C256A-12TC
AS7C256A-15TC
AS7C256A-20TC
Industrial
AS7C256A-10TI
AS7C256A-12TI
AS7C256A-15TI
AS7C256A-20TI
Package / Access time
Plastic SOJ, 300 mil
TSOP 8x13.4mm
Note: Add suffix ‘N’to the above part number for lead free parts. (Ex. AS7C256A-10JIN)
Part numbering system
AS7C
256A
–XX
X
Packages:
SRAM prefix Device number Access time J = SOJ 300 mil
T = TSOP 8x13.4mm
9/24/04; v.1.2
C or I
X
Temperature range:
C = 0 oC to 70 0C
N= Lead Free Part
I = -40C to 85C
Alliance Semiconductor
P. 8 of 9
®
AS7C256A
®
Alliance Semiconductor Corporation
2575, Augustine Drive,
Santa Clara, CA 95054
Tel: 408 - 855 - 4900
Fax: 408 - 855 - 4999
Copyright © Alliance Semiconductor
All Rights Reserved
Part Number: AS7C256A
Document Version: v.1.2
www.alsc.com
© Copyright 2003 Alliance Semiconductor Corporation. All rights reserved. Our three-point logo, our name and Intelliwatt are trademarks or registered
trademarks of Alliance. All other brand and product names may be the trademarks of their respective companies. Alliance reserves the right to make
changes to this document and its products at any time without notice. Alliance assumes no responsibility for any errors that may appear in this document.
The data contained herein represents Alliance's best data and/or estimates at the time of issuance. Alliance reserves the right to change or correct this data at
any time, without notice. If the product described herein is under development, significant changes to these specifications are possible. The information in
this product data sheet is intended to be general descriptive information for potential customers and users, and is not intended to operate as, or provide, any
guarantee or warrantee to any user or customer. Alliance does not assume any responsibility or liability arising out of the application or use of any product
described herein, and disclaims any express or implied warranties related to the sale and/or use of Alliance products including liability or warranties related
to fitness for a particular purpose, merchantability, or infringement of any intellectual property rights, except as express agreed to in Alliance's Terms and
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Sale. The purchase of products from Alliance does not convey a license under any patent rights, copyrights; mask works rights, trademarks, or any other
intellectual property rights of Alliance or third parties. Alliance does not authorize its products for use as critical components in life-supporting systems
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