参数资料
| 型号： | LTC4081EDD#TRPBF |
| 厂商： | Linear Technology |
| 文件页数： | 20/24页 |
| 文件大小： | 0K |
| 描述： | IC USB POWER MANAGER 10-DFN |
| 标准包装： | 2,500 |
| 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： | 3.75 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-WFDFN 裸露焊盘 |
| 供应商设备封装： | 10-DFN（3x3） |
| 包装： | 带卷 (TR) |
LTC4081
APPLICATIO S I FOR ATIO
NTC Trip Point Error
When a 1% resistor is used for R HOT , the major error in the 40°C
trip point is determined by the tolerance of the NTC thermistor.
A typical 100k NTC thermistor has ±10% tolerance. By look-
ing up the temperature coef?cient of the thermistor at 40°C,
the tolerance error can be calculated in degrees centigrade.
Consider the Vishay NTHS0603N01N1003J thermistor, which
has a temperature coef?cient of –4%/°C at 40°C. Dividing
SWITCHING REGULATOR
Setting the Buck Converter Output Voltage
The LTC4081 regulator compares the FB pin voltage with
an internal 0.8V reference to generate an error signal at the
output of the error ampli?er. A voltage divider from V OUT
to ground (as shown in the Block Diagram) programs the
output voltage via FB using the formula:
V OUT = 0 . 8 V ? ? 1 +
thetolerancebythetemperaturecoef?cient,±5%/(4%/°C)=
±1.25°C, gives the temperature error of the hot trip point.
?
?
R7 ?
R 8 ? ?
? COLD ? 1 ? ? 100
? 6 . 14 R HOT ?
ThecoldtrippointerrordependsonthetoleranceoftheNTC
thermistor and the degree to which the ratio of its value at
0°C and its value at 40°C varies from 6.14 to 1. Therefore,
the cold trip point error can be calculated using the tolerance,
TOL, the temperature coef?cient of the thermistor at 0°C, TC
(in %/°C), the value of the thermistor at 0°C, R COLD , and the
value of the thermistor at 40°C, R HOT . The formula is:
? 1 + TOL R ?
Temperature Error ( ° C ) =
TC
For example, the Vishay NTHS0603N01N1003J thermistor
with a tolerance of ±5%, TC of –5%/°C and R COLD /R HOT of
6.13, has a cold trip point error of:
Keeping the current low (<5μA) in these resistors maxi-
mizes ef?ciency, but making them too low may allow stray
capacitance to cause noise problems and reduce the phase
margin of the error amp loop. To improve the frequency
response, a phase-lead capacitor (C PL ) of approximately
10pF can be used. Great care should be taken to route the
FB line away from noise sources, such as the inductor or
the SW line.
Inductor Selection
The value of the inductor primarily determines the cur-
rent ripple in the inductor. The inductor ripple
current Δ I L decreases with higher inductance and
increases with higher V IN or V OUT :
? ? 6 . 14 ? 6 . 13 ? 1 ? ? ? 100
? 5
? ? 1 ? OUT ?
? 1 + 0.05 ?
Temperature Error ( ° C ) =
= ? 0 . 95 ° C , 1 . 05 ° C
Δ I L =
V OUT ? V ?
f OSC ? L ? V IN ?
4081f
20
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相关代理商/技术参数 |
参数描述 |
|---|---|
| LTC4085 | 制造商:LINER 制造商全称:Linear Technology 功能描述:High Efficiency Battery Charger/USB Power Manager |
| LTC4085-1 | 制造商:LINER 制造商全称:Linear Technology 功能描述:USB Power Manager with Ideal Diode Controller and 4.1V Li-Ion Charger |
| LTC4085-3 | 制造商:LINER 制造商全称:Linear Technology 功能描述:USB Power Manager with Ideal Diode Controller and 3.95V Li-Ion Charger |
| LTC4085EDE | 制造商:Linear Technology 功能描述:USB Power Manager 14-Pin DFN EP |
| LTC4085EDE#PBF | 功能描述:IC USB POWER MANAGER 14-DFN RoHS:是 类别:集成电路 (IC) >> PMIC - 电池管理 系列:- 其它有关文件:STC3100 View All Specifications 特色产品:STC3100 - Battery Monitor IC 标准包装:4,000 系列:- 功能:燃料，电量检测计/监控器 电池化学:锂离子（Li-Ion） 电源电压:2.7 V ~ 5.5 V 工作温度:-40°C ~ 85°C 安装类型:表面贴装 封装/外壳:8-TSSOP，8-MSOP（0.118"，3.00mm 宽） 供应商设备封装:8-MiniSO 包装:带卷 (TR) 其它名称:497-10526-2 |
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