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
Pentium
TM
, PowerPC
TM
, 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 (t
AA
, t
RC
, t
WC
) of 10/12/15/20 ns with output enable access times (t
OE
) 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
Voltage on V
CC
relative to GND
Voltage on any pin relative to GND
Power dissipation
Storage temperature (plastic)
Ambient temperature with V
CC
applied
DC current into outputs (low)
Symbol
V
t1
V
t2
P
D
T
stg
T
bias
I
OUT
Min
–0.5
–0.5
–
–65
–55
–
Max
+7.0
V
CC
+ 0.5
1.0
+150
+125
20
Unit
V
V
W
o
C
o
C
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
H
L
L
L
WE
X
H
H
L
OE
X
H
L
X
High Z
High Z
D
OUT
D
IN
Data
Mode
Standby (I
SB
, I
SB1
)
Output disable (I
CC
)
Read (I
CC
)
Write (I
CC
)
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
Supply voltage
Input voltage
Ambient operating temperature
commercial
industrial
Symbol
V
CC
V
IH**
V
IL*
T
A
T
A
Min
4.5
2.2
-0.5
0
–40
Typical
5.0
–
–
–
–
Max
5.5
V
CC
+0.5
0.8
70
85
Unit
V
V
V
o
C
o
C
*
V
IL
min = –1.0V for pulse width less than 5ns.
**
V
IH
max = V
CC
+ 2.0V for pulse width less than 5ns.
DC operating characteristics (over the operating range)
The P87LPC778 is a 20-pin packaged microcontroller that can achieve highly integrated, low-cost solutions under a wide range of performance requirements. As a member of the Philips small package serie...
[align=center][size=4]Teardown Boy vs Raspberry Pi (Part 1)[/size][/align][align=left][size=3] I would like to thank the EEWORLD community for providing me with an opportunity to teardown the Raspberr...
Summary of digital logic design : Pipeline and reusePipeline : Each level does its own work, and each processing process has its own exclusive hardware resources. The previous level is done, and the n...
As shown in the figure, the LM358 is powered by a single 15V power supply, the voltage of the 6th pin (-) is 1.66V, and the 5th pin (+) is pulled high or low through the output pin of the IC. The phen...
With the booming electronics industry, vision systems have become a leader in the electronics automation sector. However, the delicate nature of electronic products often affects product yields due...[Details]
On August 24th, media outlets reported, citing sources, that NavInfo, a listed company on the A-share market, is nearing completion in its acquisition of the intelligent driving c...[Details]
Zos Automotive Research Institute released the "2025
Smart Cockpit
Tier 1 Research Report (Domestic Edition)."
This report analyzes the operating conditions of more than a dozen ...[Details]
In June 2014, the Ministry of Industry and Information Technology issued 4G FD-LTE licenses to China Unicom and China Telecom. Together with the 4G TD-LTE licenses issued to China Mobile, China Uni...[Details]
There are basically three causes of spontaneous combustion of electric vehicles: The first is that the battery components are punctured or suffer fatal damage due to a collision accident, and part ...[Details]
Permanent magnets are essential components in a wide range of household and industrial devices. They are particularly crucial in the renewable energy sector, including electric vehicle motors. Curr...[Details]
Analog Devices held a third-quarter fiscal 2025 earnings conference call. Vincent T. Roche, CEO and Chairman of the Board, and Richard C. Puccio, Executive Vice President and Chief Financial Office...[Details]
Most cameras on the market use chips manufactured by Japanese companies like Sony, Sharp, Panasonic, and LG. South Korea now has the capability to produce chips, but the quality is somewhat inferio...[Details]
I believe everyone has heard of memory. If your computer is slow, your experts may recommend upgrading it to a larger capacity. But what exactly is computer memory used for? Why does memory capacit...[Details]
The Waveshare ESP32-P4-ETH is a compact ESP32-P4 development board with Ethernet and PoE support. It looks very similar to the Olimex ESP32-P4-DevKit, minus the pUEXT connector. However, we've also...[Details]
As the power density of modern electronic systems continues to increase, effective thermal management has become critical to ensuring system performance, reliability, and longevity—especially in hi...[Details]
With the rapid development of the automotive industry, automotive requirements for control, communication, and network management are becoming increasingly stringent. Hardware platforms based on 32...[Details]
Perhaps due to the stereotypes surrounding electronic products, many owners of pure electric vehicles have questions about charging. What's the correct way to charge? How can charging slow down bat...[Details]
introduction
Commercial air conditioner PCBs involve both high-voltage and low-voltage power. The power supply for commercial air conditioners often passes through the controller. This forces ...[Details]
introduction
Whether in the automotive entertainment or home theater system markets, consumers continue to demand more channels and speakers, each capable of handling higher audio po...[Details]
MCU
京公网安备 11010802033920号
EEWORLD
