参数资料
| 型号： | ISL12082IUZ-T |
| 厂商： | Intersil |
| 文件页数： | 17/26页 |
| 文件大小： | 0K |
| 描述： | IC RTC I2C LO-POWER 10-MSOP |
| 标准包装： | 2,500 |
| 类型： | 时钟/日历 |
| 特点： | 警报器，闰年，监视计时器 |
| 时间格式： | HH:MM:SS:hh（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： | 表面贴装 |
| 封装/外壳： | 10-TFSOP，10-MSOP（0.118"，3.00mm 宽） |
| 供应商设备封装： | 10-MSOP |
| 包装： | 带卷 (TR) |
24
FN6731.3
November 24, 2008
margin should be included if periods of very warm
temperature operation are expected.
Example 1. Calculating Backup Time Given
Voltages and Capacitor Value
VCC = 5.0V, the voltage at VBAT will approach 4.7V as the
diode turns off completely. The ISL12082 is specified to
operate down to VBAT = 1.8V. The capacitance
charge/discharge equation is used to estimate the total
backup time as shown in Equation 10:
Rearranging gives Equation 11.
CBAT is the backup capacitance and dV is the change in
voltage from fully charged to loss of operation. Note that
ITOT is the total of the supply current of the ISL12082 (IBAT)
plus the leakage current of the capacitor and the diode, ILKG.
In these calculations, ILKG is assumed to be extremely small
and will be ignored. If an application requires extended
operation at temperatures over +50°C, these leakages will
increase and hence reduce backup time.
Note that IBAT changes with VBAT almost linearly (see
“Typical Performance Curves” on page 7). This allows us to
make an approximation of IBAT, using a value midway
between the two endpoints. The typical linear equation for
Using this equation to solve for the average current given 2
voltage points gives Equation 13:
Combining with Equation 11 gives the equation for backup
time in Equation 14:
where:
CBAT = 0.47F
VBAT2 = 4.7V
VBAT1 = 1.8V
ILKG = 0 (assumed minimal)
TBACKUP = 0.47 * (2.9) / 4.38E-7 = 3.107E6 sec
Since there are 86,400 seconds in a day, this corresponds to
35.96 days. If the 30% tolerance is included for capacitor
and supply current tolerances, then worst case backup time
would be:
Example 2. Calculating a Capacitor Value for a
Given Backup Time
Referring to Figure 20 again, the capacitor value needs to be
calculated to give 2 months (60 days) of backup time, given
VCC = 5.0V. As in Example 1, the VBAT voltage will vary from
4.7V down to 1.8V. We will need to rearrange Equation 11 to
solve for capacitance in Equation 16:
Using the terms previously, this Equation 16 becomes
Equation 17:
Where:
TBACKUP = 60 days*86,400 sec/day = 5.18 E6 seconds
IBATAVG = 4.387 E-7 A (same as Example 1)
ILKG = 0 (assumed)
VBAT2 = 4.7V
VBAT1 = 1.8VSolving gives
CBAT = 5.18 E6*(4.387 E-7)/(2.9) = 0.784F
If the 30% tolerance is included for tolerances, then worst
case capacitor value would be as shown in
Equation 18.
FIGURE 20. SUPERCAPACITOR CHARGING CIRCUIT
2.7V TO 5.5V
VCC
VBAT
GND
1N4148
CBAT
I = CBAT*dV/dT
(EQ. 10)
dT = CBAT*dV/ITOT to solve for backup time.
(EQ. 11)
IBAT = 1.031E-7*(VBAT) + 1.036E-7A
(EQ. 12)
IBATAVG = 5.155E-8*(VBAT2 + VBAT1) + 1.036E-7A
(EQ. 13)
TBACKUP = CBAT*(VBAT2 - VBAT1)/(IBATAVG + ILKG)
(EQ. 14)
seconds
(EQ. 15)
C
BAT
0.70
35.96
25.2
=
days
=
CBAT = dT*I/dV
(EQ. 16)
CBAT = TBACKUP*(IBATAVG + ILKG)/(VBAT2 - VBAT1)
(EQ. 17)
CBAT = 1.3*0.784 = 1.02F
(EQ. 18)
ISL12082
相关PDF资料 |
PDF描述 |
|---|---|
| VI-BN2-MV | CONVERTER MOD DC/DC 15V 150W |
| MS3102A36-8S | CONN RCPT 47POS BOX MNT W/SCKT |
| MS27466T21F11P | CONN RCPT 11POS WALL MT W/PINS |
| ISL23418TFUZ-T7A | IC DGTL POT 1CH 100K 10MSOP |
| D38999/26WH21PA | CONN PLUG 21POS STRAIGHT W/PINS |
相关代理商/技术参数 |
参数描述 |
|---|---|
| ISL1208EVAL | 功能描述:电源管理IC开发工具 EVALRD FOR ISL1208 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 |
| ISL1208IB8 | 功能描述:IC RTC/CALENDAR I2C 8-SOIC RoHS:否 类别:集成电路 (IC) >> 时钟/计时 - 实时时钟 系列:- 产品培训模块:Obsolescence Mitigation Program 标准包装:1 系列:- 类型:时钟/日历 特点:警报器，闰年，SRAM 存储容量:- 时间格式:HH:MM:SS（12/24 小时） 数据格式:YY-MM-DD-dd 接口:SPI 电源电压:2 V ~ 5.5 V 电压 - 电源，电池:- 工作温度:-40°C ~ 85°C 安装类型:表面贴装 封装/外壳:8-WDFN 裸露焊盘 供应商设备封装:8-TDFN EP 包装:管件 |
| ISL1208IB8-TK | 功能描述:IC RTC/CALENDAR I2C 8-SOIC RoHS:否 类别:集成电路 (IC) >> 时钟/计时 - 实时时钟 系列:- 产品培训模块:Obsolescence Mitigation Program 标准包装:1 系列:- 类型:时钟/日历 特点:警报器，闰年，SRAM 存储容量:- 时间格式:HH:MM:SS（12/24 小时） 数据格式:YY-MM-DD-dd 接口:SPI 电源电压:2 V ~ 5.5 V 电压 - 电源，电池:- 工作温度:-40°C ~ 85°C 安装类型:表面贴装 封装/外壳:8-WDFN 裸露焊盘 供应商设备封装:8-TDFN EP 包装:管件 |
| ISL1208IB8Z | 功能描述:实时时钟 I2C REAL TIME CLOCK/ CALENDAR 8LD 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 |
| ISL1208IB8ZR5291 | 功能描述:实时时钟 I2CAL TIME CLK/CLNDR ALL BATRY MODE TESTS 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 |
发布紧急采购，3分钟左右您将得到回复。