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参数资料
| 型号： | LTC3520EUF#PBF |
| 厂商： | Linear Technology |
| 文件页数： | 12/24页 |
| 文件大小： | 0K |
| 描述： | IC REG BUCK BOOST SYNC ADJ 24QFN |
| 标准包装： | 91 |
| 类型： | 降压（降压），升压（升压） |
| 输出类型： | 可调式 |
| 输出数： | 2 |
| 输出电压： | 0.8 V ~ 5.5 V |
| 输入电压： | 2.2 V ~ 5.5 V |
| PWM 型： | 电流模式，混合 |
| 频率 - 开关： | 100kHz ~ 2MHz |
| 电流 - 输出： | 600mA，1A |
| 同步整流器： | 是 |
| 工作温度： | -40°C ~ 85°C |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 24-WFQFN 裸露焊盘 |
| 包装： | 管件 |
| 供应商设备封装： | 24-QFN 裸露焊盘（4x4） |
| 产品目录页面： | 1334 (CN2011-ZH PDF) |
LTC3520
OPERATION
This leads to a reduced output current capability at large
step-down ratios. In contrast, the LTC3520 performs cur-
rent limiting prior to the addition of the slope compensation
ramp and therefore achieves a peak inductor current limit
that is independent of duty cycle.
Soft-Start
The buck converter incorporates a voltage mode soft-start
circuit which is adjustable via the value of an external
soft-start capacitor, C SS . The typical soft-start duration is
given by the following equation:
t SS (ms) = 0.15C SS (nF)
The buck converter remains in regulation during soft-start
and will therefore respond to output load transients which
occur during this time. In addition, the output voltage rise-
time has minimal dependency on the size of the output
capacitor or load current.
Error Ampli?er and Compensation
The LT3520 buck converter utilizes an internal trans-
conductance error ampli?er. Compensation of the feed-
back loop is performed internally to reduce the size of the
application circuit and simplify the design process. The
compensation network has been designed to allow use of
a wide range of output capacitors while simultaneously
ensuring a rapid response to load transients.
When the input voltage is signi?cantly greater than the
output voltage, the buck-boost converter operates in
buck mode. Switch D turns on continuously and switch C
remains off. Switches A and B are pulse width modulated
to produce the required duty cycle to support the output
regulation voltage. As the input voltage decreases, switch
A remains on for a larger portion of the switching cycle.
When the duty cycle reaches approximately 85%, the
switch pair AC begins turning on for a small fraction of the
switching period. As the input voltage decreases further,
the AC switch pair remains on for longer durations and
the duration of the BD phase decreases proportionally. As
the input voltage drops below the output voltage, the AC
phase will eventually increase to the point that there is no
longer any BD phase. At this point, switch A remains on
continuously while switch pair CD is pulse width modu-
lated to obtain the desired output voltage. In this case, the
converter is operating solely in boost mode.
This switching algorithm provides a seamless transition
between operating modes and eliminates discontinuities
in average inductor current, inductor current ripple, and
loop transfer function throughout all three operational
modes. These advantages result in increased ef?ciency
and stability in comparison to the traditional four-switch
buck-boost converter.
L
BUCK-BOOST CONVERTER OPERATION
PV IN1
A
SW1A
SW1B
V OUT1
D
PWM Mode Operation
When the PWM pin is held high, the LTC3520 buck-boost
converter operates in a constant-frequency PWM mode us-
B
C
ing voltage mode control. A proprietary switching algorithm
allows the converter to switch between buck, buck-boost,
LTC3520
PGND1
PGND1
3520 F01
and boost modes without discontinuity in inductor cur-
rent or loop characteristics. The switch topology for the
Figure 1. Buck-Boost Switch Topology
buck-boost converter is shown in Figure 1.
3520fa
12
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相关代理商/技术参数 |
参数描述 |
|---|---|
| LTC3520EUF-TRPBF | 制造商:LINER 制造商全称:Linear Technology 功能描述:Synchronous 1A Buck-Boost and 600mA Buck Converters |
| LTC3520IUF#PBF | 功能描述:IC REG BUCK BOOST SYNC ADJ 24QFN RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 开关稳压器 系列:- 设计资源:Design Support Tool 标准包装:1 系列:- 类型:升压（升压） 输出类型:固定 输出数:1 输出电压:3V 输入电压:0.75 V ~ 2 V PWM 型:- 频率 - 开关:- 电流 - 输出:100mA 同步整流器:是 工作温度:-40°C ~ 85°C 安装类型:表面贴装 封装/外壳:SOT-23-5 细型，TSOT-23-5 包装:剪切带 (CT) 供应商设备封装:TSOT-23-5 其它名称:AS1323-BTTT-30CT |
| LTC3520IUF#TRPBF | 功能描述:IC REG BUCK BOOST SYNC ADJ 24QFN RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 开关稳压器 系列:- 设计资源:Design Support Tool 标准包装:1 系列:- 类型:升压（升压） 输出类型:固定 输出数:1 输出电压:3V 输入电压:0.75 V ~ 2 V PWM 型:- 频率 - 开关:- 电流 - 输出:100mA 同步整流器:是 工作温度:-40°C ~ 85°C 安装类型:表面贴装 封装/外壳:SOT-23-5 细型，TSOT-23-5 包装:剪切带 (CT) 供应商设备封装:TSOT-23-5 其它名称:AS1323-BTTT-30CT |
| LTC3521 | 制造商:LINER 制造商全称:Linear Technology 功能描述:Wide VIN, 1A Buck-Boost DC/DC and Dual 600mA Buck DC/DC Converters |
| LTC3521EFE#PBF | 功能描述:IC REG BUCK BST SYNC ADJ 20TSSOP RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 开关稳压器 系列:- 标准包装:250 系列:- 类型:降压（降压） 输出类型:固定 输出数:1 输出电压:1.2V 输入电压:2.05 V ~ 6 V PWM 型:电压模式 频率 - 开关:2MHz 电流 - 输出:500mA 同步整流器:是 工作温度:-40°C ~ 85°C 安装类型:表面贴装 封装/外壳:6-UFDFN 包装:带卷 (TR) 供应商设备封装:6-SON（1.45x1） 产品目录页面:1032 (CN2011-ZH PDF) 其它名称:296-25628-2 |
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