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参数资料
| 型号： | LTC4002EDD-8.4#TRPBF |
| 厂商： | Linear Technology |
| 文件页数： | 13/16页 |
| 文件大小： | 0K |
| 描述： | IC CHARGER BATTERY LI-ION 10-DFN |
| 标准包装： | 2,500 |
| 功能： | 充电管理 |
| 电池化学： | 锂离子（Li-Ion） |
| 电源电压： | 8.9 V ~ 22 V |
| 工作温度： | -40°C ~ 85°C |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 10-WFDFN 裸露焊盘 |
| 供应商设备封装： | 10-DFN（3x3） |
| 包装： | 带卷 (TR) |
LTC4002
APPLICATIO S I FOR ATIO
Input and Output Capacitors
Since the input capacitor is assumed to absorb all input
switching ripple current in the converter, it must have an
adequate ripple current rating. Worst-case RMS ripple cur-
rent is approximately one-half of output charge current.
Actual capacitance value is not critical. Solid tantalum
capacitors have a high ripple current rating in a relatively
small surface mount package, but caution must be used
when tantalum capacitors are used for input bypass. High
input surge currents can be created when the adapter is
hot-plugged to the charger and solid tantalum capacitors
have a known failure mechanism when subjected to very
high turn-on surge currents. Selecting the highest pos-
sible voltage rating on the capacitor will minimize prob-
lems. Consult with the manufacturer before use.
The selection of output capacitor C OUT is primarily deter-
mined by the ESR required to minimize ripple voltage and
load step transients. The output ripple ? V OUT is approxi-
mately bounded by:
Switching ripple current splits between the battery and the
output capacitor depending on the ESR of the output ca-
pacitor and the battery impedance. EMI considerations
usually make it desirable to minimize ripple current in the
battery leads. Ferrite beads or an inductor may be added
to increase battery impedance at the 500kHz switching
frequency. If the ESR of the output capacitor is 0.2 ? and
the battery impedance is raised to 4 ? with a bead or induc-
tor, only 5% of the current ripple will flow in the battery.
Design Example
As a design example, take a charger with the following
specifications: V IN = 5V to 22V, V BAT = 4V nominal, I BAT =
1.5A, f OSC = 500kHz, see Figure 2.
First, calculate the SENSE resistor :
R SENSE = 100mV/1.5A = 68m ?
Choose the inductor for about 65% ripple current at the
maximum V IN :
? V OUT ≤ ? I L ? ESR +
8 f OSC OUT ?
?
( 500 kHz )( 0 . 65 )( 1 . 5 A ) ? 22 V ?
?
?
1 ?
C
L =
4 V ? 4 V ?
? 1 – ? = 6 . 713 μ H
Since ? I L increases with input voltage, the output ripple is
highest at maximum input voltage. Typically, once the ESR
Selecting a standard value of 6.8 μ H results in a maximum
ripple current of :
( 500 kHz ) ( 6 . 8 μ H ) ? 22 V ?
requirement is satisfied, the capacitance is adequate for
filtering and has the necessary RMS current rating.
? I L =
4 V ? 4 V ?
? 1 – ? = 962 . 6 mA
4002f
13
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相关代理商/技术参数 |
参数描述 |
|---|---|
| LTC4002ES8 | 制造商:LINER 制造商全称:Linear Technology 功能描述:Standalone Li-Ion Switch Mode Battery Charger |
| LTC4002ES8-4.2 | 功能描述:IC CHARGER BATTERY LI-ION 8-SOIC RoHS:否 类别:集成电路 (IC) >> PMIC - 电池管理 系列:- 标准包装:61 系列:- 功能:电源管理 电池化学:锂离子（Li-Ion）、锂聚合物（Li-Pol） 电源电压:4.35 V ~ 5.5 V 工作温度:-40°C ~ 85°C 安装类型:表面贴装 封装/外壳:22-WFDFN 裸露焊盘 供应商设备封装:22-DFN（6x3）裸露焊盘 包装:管件 |
| LTC4002ES8-4.2#PBF | 功能描述:IC CHARGER BATTERY LI-ION 8-SOIC RoHS:是 类别:集成电路 (IC) >> PMIC - 电池管理 系列:- 标准包装:61 系列:- 功能:电源管理 电池化学:锂离子（Li-Ion）、锂聚合物（Li-Pol） 电源电压:4.35 V ~ 5.5 V 工作温度:-40°C ~ 85°C 安装类型:表面贴装 封装/外壳:22-WFDFN 裸露焊盘 供应商设备封装:22-DFN（6x3）裸露焊盘 包装:管件 |
| LTC4002ES8-4.2#TR | 功能描述:IC CHARGER BATTERY LI-ION 8-SOIC RoHS:否 类别:集成电路 (IC) >> PMIC - 电池管理 系列:- 标准包装:61 系列:- 功能:电源管理 电池化学:锂离子（Li-Ion）、锂聚合物（Li-Pol） 电源电压:4.35 V ~ 5.5 V 工作温度:-40°C ~ 85°C 安装类型:表面贴装 封装/外壳:22-WFDFN 裸露焊盘 供应商设备封装:22-DFN（6x3）裸露焊盘 包装:管件 |
| LTC4002ES8-4.2#TRPBF | 功能描述:IC CHARGER BATTERY LI-ION 8-SOIC RoHS:是 类别:集成电路 (IC) >> PMIC - 电池管理 系列:- 标准包装:61 系列:- 功能:电源管理 电池化学:锂离子（Li-Ion）、锂聚合物（Li-Pol） 电源电压:4.35 V ~ 5.5 V 工作温度:-40°C ~ 85°C 安装类型:表面贴装 封装/外壳:22-WFDFN 裸露焊盘 供应商设备封装:22-DFN（6x3）裸露焊盘 包装:管件 |
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