The DS1220AB and DS1220AD 16k Nonvolatile SRAMs are 16,384-bit, fully static, nonvolatile SRAMs
organized as 2048 words by 8 bits. Each NV SRAM has a self-contained lithium energy source and
control circuitry which constantly monitors V
CC
for an out-of-tolerance condition. When such a condition
occurs, the lithium energy source is automatically switched on and write protection is unconditionally
enabled to prevent data corruption. The NV SRAMs can be used in place of existing 2k x 8 SRAMs
directly conforming to the popular bytewide 24-pin DIP standard. The devices also match the pinout of
the 2716 EPROM and the 2816 EEPROM, allowing direct substitution while enhancing performance.
There is no limit on the number of write cycles that can be executed and no additional support circuitry is
required for microprocessor interfacing.
1 of 8
DS1220AB/AD
READ MODE
The DS1220AB and DS1220AD execute a read cycle whenever
WE
(Write Enable) is inactive (high) and
CE (Chip Enable) and OE (Output Enable) are active (low). The unique address specified by the 11
address inputs (A0-A10) defines which of the 2048 bytes of data is to be accessed. Valid data will be
available to the eight data output drivers within t
ACC
(Access Time) after the last address input signal is
stable, providing that the
CE
and
OE
access times are also satisfied. If
CE
and
OE
access times are not
satisfied, then data access must be measured from the later-occurring signal and the limiting parameter is
either t
CO
for
CE
or t
OE
for
OE
rather than address access.
WRITE MODE
The DS1220AB and DS1220AD execute a write cycle whenever the
WE
and
CE
signals are active (low)
after address inputs are stable. The latter occurring falling edge of
CE
or
WE
will determine the start of
the write cycle. The write cycle is terminated by the earlier rising edge of
CE
or
WE
. All address inputs
must be kept valid throughout the write cycle.
WE
must return to the high state for a minimum recovery
time (t
WR
) before another cycle can be initiated. The OE control signal should be kept inactive (high)
during write cycles to avoid bus contention. However, if the output drivers are enabled (
CE
and
OE
active) then
WE
will disable the outputs in t
ODW
from its falling edge.
DATA RETENTION MODE
The DS1220AB provides full functional capability for V
CC
greater than 4.75 volts and write protects by
4.5V. The DS1220AD provides full functional capability for V
CC
greater than 4.5 volts and write protects
by 4.25V. Data is maintained in the absence of V
CC
without any additional support circuitry. The
nonvolatile static RAMs constantly monitor V
CC
. Should the supply voltage decay, the NV SRAMs
automatically write protect themselves, all inputs become “don’t care,” and all outputs become high
impedance. As V
CC
falls below approximately 3.0 volts, a power switching circuit connects the lithium
energy source to RAM to retain data. During power-up, when V
CC
rises above approximately 3.0 volts,
the power switching circuit connects external V
CC
to RAM and disconnects the lithium energy source.
Normal RAM operation can resume after V
CC
exceeds 4.75 volts for the DS1220AB and 4.5 volts for the
DS1220AD.
FRESHNESS SEAL
Each DS1220 device is shipped from Dallas Semiconductor with its lithium energy source disconnected,
guaranteeing full energy capacity. When V
CC
is first applied at a level of greater than V
TP
, the lithium
energy source is enabled for battery backup operation.
2 of 8
DS1220AB/AD
ABSOLUTE MAXIMUM RATINGS
Voltage on Any Pin Relative to Ground
Operating Temperature Range
Commercial:
Industrial:
Storage Temperature
Lead Temperature (soldering, 10s)
Note:
EDIP is wave or hand soldered only.
-0.3V to +6.0V
0°C to +70°C
-40°C to +85°C
-40°C to +85°C
+260°C
This is a stress rating only and functional operation of the device at these or any other conditions above those indicated in the operation sections of this
specification is not implied. Exposure to absolute maximum rating conditions for extended periods of time may affect reliability.
[color=#666666][font=Helvetica,]Complete electric vehicle development information (including schematic diagram_PCB_source code_technical description, etc.)[/font][/color][color=#666666][font=Helvetica...
[i=s]This post was last edited by jameswangsynnex on 2015-3-3 20:05[/i][backcolor=white][font=simsun][size=4][color=#000000]IT veteran Ji Yongqing: An old employee who has worked at Huawei for 15 year...
After the guidance of WCH technicians, I found the problem in my program. The I2C devices used in my program were inconsistent. I uploaded the correct file at the end of the article for your reference...
[color=#0000FF]This problem is not so easy to find. On the surface, it seems that there is no problem. If you don't have high requirements for interface execution efficiency, you may not find it at al...
If the ultimate form of a car is a silicon-based life form, then in
the field of
intelligent driving
, it has gradually taken on the appearance of a "veteran driver." In
the field of
the ...[Details]
1. Equipment Overview
Shell-and-tube heat exchangers are a common heat exchange device used in chemical evaporation and heating equipment. Currently, the tubesheets of shell-and-tube heat exch...[Details]
Tesla and BYD, vying for dominance in the global electric vehicle market, are reportedly considering adopting Samsung's AMOLED (active-matrix organic light-emitting diode) technology for their next...[Details]
introduction
With the development of digital and network technologies, broadcasting technology has become increasingly diversified, with the most significant trend being the transition from an...[Details]
Some time ago, I attended the 4th Energy Chemistry Forum of the Chinese Chemical Society and learned about high-energy-density and high-safety batteries. I would like to summarize and share this wi...[Details]
On August 18th, Galaxis, a specialist in integrated intelligent intralogistics robotics, officially unveiled its next-generation, ultra-narrow aisle forklift mobile robot, the "VFR Ultra-Narrow Ser...[Details]
Since its invention in the mid-1940s, the microwave oven has evolved from a humble beginning to commercial use, entering homes in the 1960s and rapidly gaining popularity. Its basic functionality a...[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]
Keysight Technologies is combining its electromagnetic simulator with Synopsys' AI-driven RF design migration flow to create an integrated design flow for migrating from TSMC's N6RF+ process techno...[Details]
A half-bridge is an inverter topology for converting DC to AC. A typical half-bridge circuit consists of two controller switches, a three-wire DC power supply, two feedback diodes, and two capacito...[Details]
Plessey Semiconductors has been acquired by Haylo Labs, which was established in March last year with a $100 million, five-year loan from Chinese technology company Goertek.
Haylo Labs w...[Details]
Tools/Materials
Yitong Chuanglian MODBUS to PROFIBUS Gateway YT-PB-03
Siemens s7-300
This article describes how to configure the YT-PB-03 MODBUS to PROFIBUS gat...[Details]
With the support and encouragement of national policies, some Internet car manufacturers have also joined the new energy vehicle manufacturing industry. From the perspective of new car manufacturer...[Details]
With growing environmental awareness, the continuous improvement of three-electric technology and the increasing deployment of infrastructure such as charging stations, the electrification of new e...[Details]
Introduction: In digital circuit calculations, there is no concept of decimal points. You know where the decimal is, but the circuit does not know where the decimal point is. Therefore, you need to...[Details]
Linux and Android
京公网安备 11010802033920号
EEWORLD
