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参数资料
| 型号： | LTC3852EUDD#TRPBF |
| 厂商： | Linear Technology |
| 文件页数： | 21/32页 |
| 文件大小： | 0K |
| 描述： | IC REG CTRLR DOUBLER PWM 24-QFN |
| 标准包装： | 2,500 |
| PWM 型： | 电流模式 |
| 输出数： | 1 |
| 频率 - 最大： | 810kHz |
| 占空比： | 99% |
| 电源电压： | 2.7 V ~ 38 V |
| 降压： | 是 |
| 升压： | 无 |
| 回扫： | 无 |
| 反相： | 无 |
| 倍增器： | 是 |
| 除法器： | 无 |
| Cuk： | 无 |
| 隔离： | 无 |
| 工作温度： | -40°C ~ 125°C |
| 封装/外壳： | 24-WFQFN 裸露焊盘 |
| 包装： | 带卷 (TR) |
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LTC3852
APPLICATIONS INFORMATION
is given to ripple current ratings, temperature and long-
term reliability. A typical application will require several
to many aluminum electrolytic capacitors in parallel. A
combination of the above mentioned capacitors will often
result in maximizing performance and minimizing overall
cost. Other capacitor types include Nichicon PL series, NEC
Neocap, Panasonic SP and Sprague 595D series. Consult
manufacturers for other speci?c recommendations.
Like all components, capacitors are not ideal. Each
capacitor has its own bene?ts and limitations. Combina-
sense voltage is progressively lowered from its maximum
programmed value to about 25% of the that value. Foldback
current limiting is disabled during soft-start or tracking.
Under short-circuit conditions with very low duty cycles,
the LTC3852 will begin cycle skipping in order to limit the
short-circuit current. In this situation the bottom MOSFET
will be dissipating most of the power but less than in normal
operation. The short-circuit ripple current is determined
by the minimum on-time t ON(MIN) of the LTC3852 (≈90ns),
the input voltage and inductor value:
tions of different capacitor types have proven to be a very
cost effective solution. Remember also to include high
Δ I L(SC) = t ON(MIN) ?
V IN
L
frequency decoupling capacitors. They should be placed
as close as possible to the power pins of the load. Any
The resulting short-circuit current is:
– Δ I L(SC)
inductance present in the circuit board traces negates
their usefulness.
I SC =
1/4MaxV SENSE
R SENSE
1
2
V OUT = 0. 8 V ? 1 + B ?
Setting Output Voltage
The LTC3852 output voltage is set by an external feedback
resistive divider carefully placed across the output,
as shown in Figure 7. The regulated output voltage is
determined by:
? R ?
? R A ?
To improve the transient response, a feed-forward ca-
pacitor, C FF , may be used. Great care should be taken to
route the V FB line away from noise sources, such as the
inductor or the SW line.
V OUT
Programming Switching Frequency
To set the switching frequency of the LTC3852, connect
a resistor, R FREQ , between FREQ/PLLFLTR and GND. The
relationship between the oscillator frequency and R FREQ
is shown in Figure 8. A 0.1μF bypass capacitor should be
connected in parallel with R FREQ .
750
700
650
600
550
500
450
400
LTC3852
V FB
R B
R A
C FF
350
300
250
20
40
60
80
100
120
140
160
3852 F07
R FREQ (kΩ)
3852 F08
Figure 7. Settling Output Voltage
Figure 8. Relationship Between Oscillator Frequency
and Resistor Connected Between FREQ/PLLFLTR and GND
Fault Conditions: Current Limit and Current Foldback
The LTC3852 includes current foldback to help limit load
current when the output is shorted to ground. If the output
falls below 40% of its nominal output level, the maximum
3852f
21
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相关代理商/技术参数 |
参数描述 |
|---|---|
| LTC3852IUDD#PBF | 功能描述:IC REG CTRLR DOUBLER PWM 24-QFN RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 切换控制器 系列:- 标准包装:2,500 系列:- PWM 型:电流模式 输出数:1 频率 - 最大:500kHz 占空比:96% 电源电压:4 V ~ 36 V 降压:无 升压:是 回扫:无 反相:无 倍增器:无 除法器:无 Cuk:无 隔离:无 工作温度:-40°C ~ 125°C 封装/外壳:24-WQFN 裸露焊盘 包装:带卷 (TR) |
| LTC3852IUDD#TRPBF | 功能描述:IC REG CTRLR DOUBLER PWM 24-QFN RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 切换控制器 系列:- 标准包装:2,500 系列:- PWM 型:电流模式 输出数:1 频率 - 最大:500kHz 占空比:96% 电源电压:4 V ~ 36 V 降压:无 升压:是 回扫:无 反相:无 倍增器:无 除法器:无 Cuk:无 隔离:无 工作温度:-40°C ~ 125°C 封装/外壳:24-WQFN 裸露焊盘 包装:带卷 (TR) |
| LTC3853EUJ#PBF | 功能描述:IC REG CTRLR BUCK PWM CM 40-QFN RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 切换控制器 系列:PolyPhase® 特色产品:LM3753/54 Scalable 2-Phase Synchronous Buck Controllers 标准包装:1 系列:PowerWise® PWM 型:电压模式 输出数:1 频率 - 最大:1MHz 占空比:81% 电源电压:4.5 V ~ 18 V 降压:是 升压:无 回扫:无 反相:无 倍增器:无 除法器:无 Cuk:无 隔离:无 工作温度:-5°C ~ 125°C 封装/外壳:32-WFQFN 裸露焊盘 包装:Digi-Reel® 产品目录页面:1303 (CN2011-ZH PDF) 其它名称:LM3754SQDKR |
| LTC3853EUJ#TRPBF | 功能描述:IC REG CTRLR BUCK PWM CM 40-QFN RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 切换控制器 系列:PolyPhase® 特色产品:LM3753/54 Scalable 2-Phase Synchronous Buck Controllers 标准包装:1 系列:PowerWise® PWM 型:电压模式 输出数:1 频率 - 最大:1MHz 占空比:81% 电源电压:4.5 V ~ 18 V 降压:是 升压:无 回扫:无 反相:无 倍增器:无 除法器:无 Cuk:无 隔离:无 工作温度:-5°C ~ 125°C 封装/外壳:32-WFQFN 裸露焊盘 包装:Digi-Reel® 产品目录页面:1303 (CN2011-ZH PDF) 其它名称:LM3754SQDKR |
| LTC3853EUJPBF | 制造商:Linear Technology 功能描述:DC-DC Controller Triple Buck 24V QFN40 |
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