- 您現(xiàn)在的位置：買賣IC網(wǎng) > PDF目錄2001 > ISL12022MIBZ-T7A (Intersil)IC RTC/CALENDAR TEMP SNSR 20SOIC PDF資料下載
參數(shù)資料
| 型號： | ISL12022MIBZ-T7A |
| 廠商： | Intersil |
| 文件頁數(shù)： | 19/31頁 |
| 文件大小： | 0K |
| 描述： | IC RTC/CALENDAR TEMP SNSR 20SOIC |
| 應(yīng)用說明： | Addressing Power Issues in Real Time Clock Appls |
| 產(chǎn)品培訓(xùn)模塊： | Solutions for Industrial Control Applications |
| 標(biāo)準(zhǔn)包裝： | 250 |
| 類型： | 時鐘/日歷 |
| 特點： | 警報器，夏令時，閏年，SRAM |
| 存儲容量： | 128B |
| 時間格式： | HH:MM:SS（12/24 小時） |
| 數(shù)據(jù)格式： | YY-MM-DD-dd |
| 接口： | I²C，2 線串口 |
| 電源電壓： | 2.7 V ~ 5.5 V |
| 電壓 - 電源，電池： | 1.8 V ~ 5.5 V |
| 工作溫度： | -40°C ~ 85°C |
| 安裝類型： | 表面貼裝 |
| 封裝/外殼： | 20-SOIC（0.295"，7.50mm 寬） |
| 供應(yīng)商設(shè)備封裝： | 20-SOIC |
| 包裝： | 帶卷 (TR) |
第1頁第2頁第3頁第4頁第5頁第6頁第7頁第8頁第9頁第10頁第11頁第12頁第13頁第14頁第15頁第16頁第17頁第18頁當(dāng)前第19頁第20頁第21頁第22頁第23頁第24頁第25頁第26頁第27頁第28頁第29頁第30頁第31頁
ISL12022M
26
FN6668.9
June 20, 2012
Application Section
Power Supply Considerations
The ISL12022M contains programmed EEPROM registers which
are recalled to volatile RAM registers during initial power-up.
These registers contain DC voltage, frequency and temperature
calibration settings. Initial power-up can be either application of
VBAT or VDD power, whichever is first. It is important that the
initial power-up meet the power supply slew rate specification to
avoid faulty EEPROM power-up recall. Also, any glitches or low
voltage DC pauses should be avoided, as these may activate
recall at a low voltage and load erroneous data into the
calibration registers. Note that a very slow VDD ramp rate
(outside data sheet limits) will almost always trigger erroneous
recall and should be avoided entirely.
Battery Backup Details
The ISL12022M has automatic switchover to battery backup
when the VDD drops below the VBAT mode threshold. A wide
variety of backup sources can be used, including standard and
rechargeable lithium, supercapacitors, or regulated secondary
sources. The serial interface is disabled in battery backup, while
the oscillator and RTC registers are operational. The SRAM
register contents are powered to preserve their contents as well.
The input voltage range for VBAT is 1.8V to 5.5V, but keep in mind
the temperature compensation only operates for VBAT >2.7V. Note
that the device is not guaranteed to operate with a VBAT < 1.8V, so
the battery should be changed before discharging to that level. It is
strongly advised to monitor the low battery indicators in the status
registers and take action to replace discharged batteries.
If a supercapacitor is used, it is possible that it may discharge to
below 1.8V during prolonged power-down. Once powered up, the
device may lose serial bus communications until both VDD and
VBAT are powered down together. To avoid that situation, including
situations where a battery may discharge deeply, the circuit in
Figure 22 can be used.
The diode, DBAT will add a small drop to the battery voltage but
will protect the circuit should battery voltage drop below 1.8V.
The jumper is added as a safeguard should the battery ever need
to be disconnected from the circuit.
The VDD negative slew rate should be limited to below the data
sheet spec (10V/ms) otherwise battery switchover can be
delayed, resulting in SRAM contents corruption and oscillator
operation interruption.
Some applications will require separate supplies for the RTC VDD
and the I2C pull-ups. This is not advised, as it may compromise the
operation of the I2C bus. For applications that do require serial bus
communication with the RTC VDD powered down, the SDA pin
must be pulled low during the time the RTC VDD ramps down to 0V.
Otherwise, the device may lose serial bus communications once
VDD is powered up, and will return to normal operation ONLY once
VDD and VBAT are both powered down together.
Layout Considerations
The ISL12022M contains a quartz crystal and requires special
handling during PC board assembly. Excessive shock and vibrations
should be avoided, especially with automated handling equipment.
Ultrasound cleaning is not advisable as it subjects the crystal to
specifications tables, which pertains to solder reflow effects on
oscillator accuracy.
The part of the package from pin 1 to 5 and from pin 16 to 20
contains the crystal. Low frequency RTC crystals are known to pick
up noise very easily if layout precautions are not followed, even
embedded within a plastic package. Most instances of erratic
clocking or large accuracy errors can be traced to the susceptibility
of the oscillator circuit to interference from adjacent high speed
clock or data lines. Careful layout of the RTC circuit will avoid noise
pickup and insure accurate clocking.
Figure 23 shows a suggested layout for the ISL12022M device.
The following main precautions should be followed:
Do not run the serial bus lines or any high speed logic lines in
the vicinity of pins 1 and 20, or under the package. These logic
level lines can induce noise in the oscillator circuit, causing
misclocking.
Add a ground trace around the device with one end terminated at
the chip ground. This guard ring will provide termination for
emitted noise in the vicinity of the RTC device
Be sure to ground pins 6 and 15 as well as pin 8 as these all
insure the integrity of the device ground
Add a 0.1F decoupling capacitor at the device VDD pin,
especially when using the 32.768kHz FOUT function.
The best way to run clock lines around the RTC is to stay outside of
the ground ring by at least a few millimeters. Also, use the VBAT
and VDD as guard ring lines as well, they can isolate clock lines
from the oscillator section. In addition, if the IRQ/FOUT pin is used
as a clock, it should be routed away from the RTC device as well.
FIGURE 22. SUGGESTED BATTERY BACKUP CIRCUIT
DBAT
CBAT
CIN
BAT43W
0.1F
VDD = 2.7V
VBAT = 1.8V
JBAT
ISL12022M
VDD
GND
VBAT
TO 3.2V
TO 5.5V
+
FIGURE 23. SUGGESTED LAYOUT FOR THE ISL12022M
FOUT
SCL
SDA
GROUND
RING
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| ISL12022MIBZR5421 | IC RTC/CALENDAR TEMP SNSR 20SOIC |
| ISL12023IVZ | IC RTC/CLDR TEMP SNSR 14-TSSOP |
| ISL12024IRTCZ | IC RTC/CALENDER 64BIT 8-TDFN |
| ISL12024IVZ | IC RTC/CALENDAR EEPROM 8-TSSOP |
| ISL12025IVZ | IC RTC/CALENDAR EEPROM 8-TSSOP |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| ISL12022MIBZ-TR5421 | 功能描述:實時時鐘 REAL TIME CLK W/MFK IMPROVED ESD AIR 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 時間格式:HH:MM:SS RTC 存儲容量: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 |
| ISL12022MR5421 | 制造商:INTERSIL 制造商全稱:Intersil Corporation 功能描述:Low Power RTC with Battery Backed SRAM, Integrated 5ppm |
| ISL12022M-R5421 | 制造商:INTERSIL 制造商全稱:Intersil Corporation 功能描述:High-Accuracy RTC Modules, Feature-Rich RTCs |
| ISL12023 | 制造商:INTERSIL 制造商全稱:Intersil Corporation 功能描述:Low Power RTC with Battery-Backed SRAM and Embedded Temp Compensation ±5ppm with Auto Daylight Saving |
| ISL12023IVZ | 功能描述:實時時鐘 REAL TIME CLK/CLNDR W/TEMP COM 14 L 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 時間格式:HH:MM:SS RTC 存儲容量: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 |
發(fā)布緊急采購，3分鐘左右您將得到回復(fù)。