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參數(shù)資料
| 型號(hào)： | M48T59Y-70MH1 |
| 廠商： | 意法半導(dǎo)體 |
| 英文描述： | 64 Kbit 8Kb x8 TIMEKEEPER SRAM |
| 中文描述： | 64千位8KB的x8 SRAM的計(jì)時(shí)器 |
| 文件頁數(shù)： | 12/17頁 |
| 文件大?。?/td> | 135K |
| 代理商： | M48T59Y-70MH1 |
Two methods are available for ascertaining how
much calibration a given M48T58/58Y may require.
The first involves simply setting the clock, letting it
run for a month and comparing it to a known
accurate reference (like WWV broadcasts). While
that may seem crude, it allows the designer to give
the end user the ability to calibrate his clock as his
environment may require, even after the final prod-
uct is packaged in a non-user serviceable enclo-
sure. All the designer has to do is provide a simple
utility that accesses the Calibration byte.
The second approach is better suited to a manu-
facturing environment, and involves the use of
some test equipment. When the Frequency Test
(FT) bit, the seventh-most significant bit in the Day
Register, is set to a ’1’, and the oscillator is running
at 32,768 Hz, the Frequency Test (Pin 1) will toggle
at 512 Hz. Any deviation from 512 Hz indicates the
degree and direction of oscillator frequency shift at
the test temperature. For example, a reading of
512.01024 Hz would indicate a +20 ppm oscillator
frequency error, requiring a -10 (WR001010) to be
loaded into the Calibration Byte for correction. Note
that setting or changing the Calibration Byte does
not affect the Frequency test output frequency.
The FT bit must be set using the same method used
to set the clock, using the Write bit.
The Frequency Test pin is an open drain output
which requires a pull-up resistor for proper opera-
tion. A 500-10k
resistor is recommended in order
to control the rise time.
For more information on calibration, see the Appli-
cation Note AN934 "TIMEKEEPER Calibration".
POWER SUPPLY DECOUPLING and UNDER-
SHOOT PROTECTION
I
CC
transients, including those produced by output
switching, can produce voltage fluctuations, result-
ing in spikes on the V
CC
bus. These transients can
be reduced if capacitors are used to store energy,
which stabilizes the V
CC
bus. The energy stored in
the bypass capacitors will be released as low going
spikes are generated or energy will be absorbed
when overshoots occur. A ceramic bypass capaci-
tor value of 0.1
μ
F (as shown in Figure 11) is rec-
ommended in order to provide the needed filtering.
In addition to transients that are caused by normal
SRAM operation, power cycling can generate
negative voltage spikes on V
CC
that drive it to
values below V
SS
by as much as one Volt. These
negative spikes can cause data corruption in the
SRAM while in battery backup mode. To protect
from these voltage spikes, it is recommeded to
connect a schottky diode from V
CC
to V
SS
(cathode
connected to V
CC
, anode to V
SS
). Schottky diode
1N5817 is recommended for through hole and
MBRS120T3 is recommended for surface mount.
CLOCK OPERATIONS
(cont’d)
AI02169
VCC
0.1
μ
F
DEVICE
VCC
VSS
Figure 11. Supply Voltage Protection
12/17
M48T58, M48T58Y
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相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| M48T59Y-70MH1E | 功能描述:實(shí)時(shí)時(shí)鐘 64K (8Kx8) 70ns RoHS:否 制造商:Microchip Technology 功能:Clock, Calendar. Alarm RTC 總線接口:I2C 日期格式:DW:DM:M:Y 時(shí)間格式:HH:MM:SS RTC 存儲(chǔ)容量:64 B 電源電壓-最大:5.5 V 電源電壓-最小:1.8 V 最大工作溫度:+ 85 C 最小工作溫度: 安裝風(fēng)格:Through Hole 封裝 / 箱體:PDIP-8 封裝:Tube |
| M48T59Y-70MH1F | 功能描述:實(shí)時(shí)時(shí)鐘 64K (8Kx8) 70ns RoHS:否 制造商:Microchip Technology 功能:Clock, Calendar. Alarm RTC 總線接口:I2C 日期格式:DW:DM:M:Y 時(shí)間格式:HH:MM:SS RTC 存儲(chǔ)容量:64 B 電源電壓-最大:5.5 V 電源電壓-最小:1.8 V 最大工作溫度:+ 85 C 最小工作溫度: 安裝風(fēng)格:Through Hole 封裝 / 箱體:PDIP-8 封裝:Tube |
| M48T59Y-70MH1TR | 制造商:STMICROELECTRONICS 制造商全稱:STMicroelectronics 功能描述:64 Kbit 8Kb x8 TIMEKEEPER SRAM |
| M48T59Y-70MH6 | 功能描述:實(shí)時(shí)時(shí)鐘 R 511-M48T59Y-70MH6E RoHS:否 制造商:Microchip Technology 功能:Clock, Calendar. Alarm RTC 總線接口:I2C 日期格式:DW:DM:M:Y 時(shí)間格式:HH:MM:SS RTC 存儲(chǔ)容量:64 B 電源電壓-最大:5.5 V 電源電壓-最小:1.8 V 最大工作溫度:+ 85 C 最小工作溫度: 安裝風(fēng)格:Through Hole 封裝 / 箱體:PDIP-8 封裝:Tube |
| M48T59Y-70MH6E | 功能描述:實(shí)時(shí)時(shí)鐘 64K (8Kx8) 70ns RoHS:否 制造商:Microchip Technology 功能:Clock, Calendar. Alarm RTC 總線接口:I2C 日期格式:DW:DM:M:Y 時(shí)間格式:HH:MM:SS RTC 存儲(chǔ)容量:64 B 電源電壓-最大:5.5 V 電源電壓-最小:1.8 V 最大工作溫度:+ 85 C 最小工作溫度: 安裝風(fēng)格:Through Hole 封裝 / 箱體:PDIP-8 封裝:Tube |
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