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| 型号： | ISL12022MAIBZ-T |
| 厂商： | Intersil |
| 文件页数： | 21/31页 |
| 文件大小： | 0K |
| 描述： | IC RTC/CALENDAR TEMP SNSR 20SOIC |
| 产品培训模块： | Solutions for Industrial Control Applications |
| 标准包装： | 1,000 |
| 类型： | 时钟/日历 |
| 特点： | 警报器，夏令时，闰年，SRAM |
| 存储容量： | 128B |
| 时间格式： | HH:MM:SS（12/24 小时） |
| 数据格式： | YY-MM-DD-dd |
| 接口： | I²C，2 线串口 |
| 电源电压： | 2.7 V ~ 5.5 V |
| 电压 - 电源，电池： | 1.8 V ~ 5.5 V |
| 工作温度： | -40°C ~ 85°C |
| 安装类型： | * |
| 封装/外壳： | * |
| 供应商设备封装： | * |
| 包装： | * |
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ISL12022MA
28
FN7575.5
September 5, 2012
The part of the package from pin 4 to 6 and from pin 15 to 17
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 22 shows a suggested layout for the ISL12022MA 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
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.
Measuring Oscillator Accuracy
The best way to analyze the ISL12022MA frequency accuracy is
to set the IRQ/FOUT pin for a specific frequency, and look at the
output of that pin on a high accuracy frequency counter (at least
7 digits accuracy). Note that the IRQ/FOUT is an drain output and
will require a pull-up resistor.
Using the 1.0Hz output frequency is the most convenient as the
ppm error is expressed in Equation 6:
Other frequencies may be used for measurement but the error
calculation becomes more complex. Use the FOUT output and a
frequency counter for the most accurate results. Also, when the
proper layout guidelines above are observed, the oscillator
should start-up in most circuits in less than one second.
Temperature Compensation Operation
The ISL12022MA temperature compensation feature needs to
be enabled by the user. This must be done in a specific order as
follows.
Read register 0Dh, the BETA register. This register contains the
5-bit BETA trimmed value, which is automatically loaded on
initial power-up. Mask off the 5 LSB’s of the value just read.
Bit 7 of the BETA register is the master enable control for
temperature sense operation. Set this to “1” to allow
continuous temperature frequency correction. Frequency
correction will then happen every 60 seconds with VDD
applied.
Bits 5 and 6 of the BETA register control temperature
compensation in battery backup mode (see Table 16). Set the
values for the operation desired.
Write back to register 0Dh making sure not to change the 5
LSB values, and include the desired compensation control bits.
Note that every time the BETA register is written with the TSE bit
= 1, a temperature compensation cycle is instigated and a new
correction value will be loaded into the FATR/FDTR registers (if
the temperature changed since the last conversion).
Also note that registers 0Bh and 0Ch, the ITR0 and ALPHA registers,
are READ-ONLY, and cannot be written to. Also the value for BETA is
locked and cannot be changed with a write. However, It is still a good
idea to do the bit masking when doing TSE bit changes.
Daylight Savings Time (DST) Example
DST involves setting the forward and back times and allowing the
RTC device to automatically advance the time or set the time
back. This can be done for current year, and future years. Many
regions have DST rules that use standard months, weeks and
time of the day, which permit a pre-programmed, permanent
setting.
Table 28 shows an example setup for the ISL12022MA.
FIGURE 22. SUGGESTED LAYOUT FOR THE ISL12022MA
FOUT
SCL
SDA
GROUND
RING
ppm error
F
OUT
11e6
–
=
(EQ. 6)
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相关代理商/技术参数 |
参数描述 |
|---|---|
| ISL12022M-EVAL | 制造商:Intersil Corporation 功能描述:Low Power RTC with Battery Backed SRAM, Integrated 5ppm Temperature Compensation, and Auto Daylight Saving |
| ISL12022MIBZ | 功能描述:实时时钟 REAL TIME CLK & TEMP COMPENSATED CRYSTAL RoHS:否 制造商:Microchip Technology 功能:Clock, Calendar. Alarm RTC 总线接口:I2C 日期格式:DW:DM:M:Y 时间格式:HH:MM:SS RTC 存储容量:64 B 电源电压-最大:5.5 V 电源电压-最小:1.8 V 最大工作温度:+ 85 C 最小工作温度: 安装风格:Through Hole 封装 / 箱体:PDIP-8 封装:Tube |
| ISL12022MIBZ-EVAL | 功能描述:电源管理IC开发工具 ISL12022MIBZ-EVAL DEMO BRD RoHS:否 制造商:Maxim Integrated 产品:Evaluation Kits 类型:Battery Management 工具用于评估:MAX17710GB 输入电压: 输出电压:1.8 V |
| ISL12022MIBZR5421 | 功能描述:实时时钟 REAL TIME CLK W/MFK IMPROVED ESD AIR RoHS:否 制造商:Microchip Technology 功能:Clock, Calendar. Alarm RTC 总线接口:I2C 日期格式:DW:DM:M:Y 时间格式:HH:MM:SS RTC 存储容量:64 B 电源电压-最大:5.5 V 电源电压-最小:1.8 V 最大工作温度:+ 85 C 最小工作温度: 安装风格:Through Hole 封装 / 箱体:PDIP-8 封装:Tube |
| ISL12022MIBZ-T | 功能描述:实时时钟 REAL TIME CLK & TEMP COMPENSATED CRYSTAL RoHS:否 制造商:Microchip Technology 功能:Clock, Calendar. Alarm RTC 总线接口:I2C 日期格式:DW:DM:M:Y 时间格式:HH:MM:SS RTC 存储容量:64 B 电源电压-最大:5.5 V 电源电压-最小:1.8 V 最大工作温度:+ 85 C 最小工作温度: 安装风格:Through Hole 封装 / 箱体:PDIP-8 封装:Tube |
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