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| 型号： | MAX8971EWP+T |
| 厂商： | Maxim Integrated Products |
| 文件页数： | 23/39页 |
| 文件大小： | 0K |
| 描述： | IC DCDC CHRGR LI+ 1CELL 20WLP |
| 标准包装： | 2,500 |
| 功能： | 充电管理，过压/欠压保护 |
| 电池化学： | 锂离子（Li-Ion）、锂聚合物（Li-Pol） |
| 电源电压： | 4 V ~ 7.5 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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MAX8971
Industry's Smallest 1.55A
1-Cell Li+ DC-DC Charger
The battery node should have enough capacitance to
hold the battery voltage to some minimum acceptable
system value (V SYS ) during the done to fast-charge state
transition time of 100us (t DONE2FC) .
C BAT ≥ I LOAD x t DONE2FC /(V BATREG - V SYS )
For example, if the maximum system load without a bat-
tery is 400mA (I LOAD ), and the minimum acceptable sys-
tem voltage is 3.4V (V SYS ), then the battery node should
have at least 40μF.
C BAT ≥ 400mA x 100μs/(4.2V - 3.4V) = 40μF.
Applications Information
Inductor Selection
The charger operates with a switching frequency of
4MHz and uses a 1 F H or 2.2 F H inductor. This operating
frequency allows the use of physically small inductors
while maintaining high efficiency.
The inductor’s DC current rating only needs to match
the maximum load of the application because the IC
features zero current overshoot during startup and load
transients. For optimum transient response and high effi-
ciency, choose an inductor with DC series resistance in
the 40m I to 120m I range. See Table 2 for suggested
inductors and manufacturers.
Input Capacitor Selection
The input capacitor reduces the current peaks drawn
from the input power source and reduces switching noise
in the IC. The impedance of the input capacitor at the
switching frequency should be kept very low. Ceramic
capacitors with X5R or X7R temperature characteristics
are highly recommended due to their small size, low ESR,
and small temperature coefficients. A 4.7FF capacitor
Table 2. Suggested Inductors
is recommended. For optimum noise immunity and low
input ripple, the input capacitor value can be increased.
Note that some ceramic dielectrics exhibit large capaci-
tance and ESR variation with temperature and DC bias.
Ceramic capacitors with Z5U or Y5V temperature char-
acteristics should be avoided.
Output Capacitor Selection
For the charger, the output capacitor keeps the output
voltage ripple small and ensures regulation loop stabil-
ity. The output capacitor must have low impedance at
the switching frequency. Ceramic capacitors with X5R or
X7R temperature characteristics are highly recommend-
ed due to their small size, low ESR, and small tempera-
ture coefficients. A 4.7 F F capacitor is recommended. For
optimum load-transient performance and very low output
ripple, increase the output capacitor value.
Charge Current Resistor Selection
Both the top-off current range and fast-charge cur-
rent range depends on the sensing resistor (R SNS ).
The default resistor recommended is a 47m I , 0.125W
resistor. Select a 0.125W,47m I 2% sense resistor, e.g.,
Panasonic ERJ2BWGR047. This is a standard value.
P RSNS = I CHARGE 2 x R SNS
P RSNS = 1.5 2 x 0.047
P RSNS = 0.105W
The charge current step (I CHARGE ) is calculated using
equation below:
I CHARGE_STEP = V( CHGCC<> )/R SNS
Table 3 below shows the charge current settings for two
sensing resistors.
I CHARGE_CURRENT_STEP = V( TOPOFF<> )/R SNS
MANUFACTURER
FDK
Murata
Coilcraft
TDK
TOKO
TOKO
Murata
SERIES
MIPSA2520D1R0
LQM2HPN_G0
EPL2014
MLP2520S
MIPF2520
DFE252012C
LQM32PN1R0MG0
INDUCTANCE
(μH)
1.0
1.0
1.0
1.0
2.2
1
1
ESR ( I )
0.08
0.05
0.059
0.06
0.05
0.06
0.06
CURRENT
RATING
(mA)
1500
1600
1600
1500
1500
2500
1800
DIMENSIONS
2.5mm x 2.0mm x 1.2mm = 6mm 3
2.5mm x 2.0mm x 0.6mm = 3mm 3
2.0mm x 2.0mm x 1.4mm = 5.6mm 3
2.0mm x 2.5mm x 1.0mm = 5mm 3
2.5mm x 2.0mm x 1.0mm = 5mm 3
2.5 x 2.0 x 1.2 = 6mm 3
3.2 x 2.5 x 0.9 = 7.2mm3
Maxim Integrated
23
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相关代理商/技术参数 |
参数描述 |
|---|---|
| MAX8971QEWP+T | 功能描述:电池管理 Switch-Mode Li+ Charger RoHS:否 制造商:Texas Instruments 电池类型:Li-Ion 输出电压:5 V 输出电流:4.5 A 工作电源电压:3.9 V to 17 V 最大工作温度:+ 85 C 最小工作温度:- 40 C 封装 / 箱体:VQFN-24 封装:Reel |
| MAX8973AEWI+ | 制造商:Maxim Integrated Products 功能描述:HIGH CURRENT, MULTI-PHASE DC/DC STEP-DOWN CONVERTER - Rail/Tube |
| MAX8973AEWI+T | 制造商:Maxim Integrated Products 功能描述:HIGH CURRENT, MULTI-PHASE DC/DC STEP-DOWN CONVERTER - Tape and Reel |
| MAX8982AEWO+T | 制造商:Maxim Integrated Products 功能描述:POWER MANAGEMENT IC FOR ICERA E400/E450 PLATFORM-MINI CARD - Tape and Reel |
| MAX8982EWO+T | 功能描述:PMIC 解决方案 PMIC for ICERA E400/E450 Platform RoHS:否 制造商:Texas Instruments 安装风格:SMD/SMT 封装 / 箱体:QFN-24 封装:Reel |
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