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参数资料
| 型号： | LTC3533EDE#TRPBF |
| 厂商： | Linear Technology |
| 文件页数： | 8/16页 |
| 文件大小： | 0K |
| 描述： | IC REG BUCK BOOST SYNC ADJ 14DFN |
| 标准包装： | 2,500 |
| 类型： | 降压（降压），升压（升压） |
| 输出类型： | 可调式 |
| 输出数： | 1 |
| 输出电压： | 1.8 V ~ 5.25 V |
| 输入电压： | 1.8 V ~ 5.5 V |
| PWM 型： | Burst Mode? |
| 频率 - 开关： | 300kHz ~ 2MHz |
| 电流 - 输出： | 2A |
| 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： | 14-WFDFN 裸露焊盘 |
| 包装： | 带卷 (TR) |
| 供应商设备封装： | 14-DFN-EP（4x3） |
LTC3533
OPERATION
Error Ampli?er
The error ampli?er is a voltage mode ampli?er. The loop
compensation components are con?gured around the
ampli?er (from FB to V C ) to obtain stability of the converter.
For improved bandwidth, an additional RC feed-forward
network can be placed across the upper feedback divider
resistor. The voltage on the RUN/SS pin clamps the error
ampli?er output, V C , to provide a soft-start function.
Supply Current Limits
There are two different supply current limit circuits in the
LTC3533, working consecutively, each having internally
?xed thresholds which vary inversely with V IN .
The ?rst circuit is a current limit ampli?er, sourcing cur-
rent into FB to drop the output voltage, should the peak
input current exceed 4.5A typical. This method provides a
closed loop means of clamping the input current. During
conditions where V OUT is near ground, such as during a
short circuit or startup, this threshold is cut to 750mA,
providing a fold-back feature. For this current limit feature
to be most effective, the Thevenin resistance from FB to
ground should be greater than 100k.
Should the peak input current exceed 7A typical, the second
circuit, a high speed peak current limit comparator, shuts
off PMOS switch A. The delay to output of this comparator
is typically 50ns.
Reverse Current Limit
During ?xed frequency operation, the LTC3533 operates in
forced continuous conduction mode. The reverse current
output through switch D. Should this negative inductor
current exceed 500mA typical, the LTC3533 shuts off
switch D.
Four-Switch Control
Figure 1 shows a simpli?ed diagram of how the four in-
ternal switches are connected to the inductor, V IN , V OUT
and GND.Figure 2 shows the regions of operation for the
LTC3533 as a function of the control voltage, V C .
Dependent on V C ’s magnitude, the LTC3533 will operate
in either buck, buck/boost or boost mode. The four power
switches are properly phased so the transfer between op-
erating modes is continuous, smooth and transparent to
the user. When V IN approaches V OUT the buck/boost region
is entered, where the conduction time of the four switch
region is typically 150ns. Referring to Figures 1 and 2, the
various regions of operation will now be described.
Buck Region (V IN > V OUT )
Switch D is always on and switch C is always off during
this mode. When the control voltage, V C , is above volt-
age V1, switch A begins to switch. During the off time of
switch A, synchronous switch B turns on for the remainder
of the period. Switches A and B will alternate similar to a
typical synchronous buck regulator. As the control volt-
age increases, the duty cycle of switch A increases until
the maximum duty cycle of the converter in buck mode
reaches D MAX_BUCK , given by:
D MAX_BUCK = 100 – D4 SW %
where D4 SW = duty cycle % of the four switch range.
limit comparator monitors the inductor current from the
85%
D MAX
BOOST
V4 ( ≈ 1.5V)
PV IN
11
PV OUT
9
D MIN
BOOST
A ON, B OFF
PWM CD SWITCHES
BOOST REGION
V3 ( ≈ 1.15V)
PMOS A
PMOS D
D MAX
BUCK
FOUR SWITCH PWM
BUCK/BOOST REGION
V2 ( ≈ 1V)
SW1
3
L1
SW2
7
D ON, C OFF
PWM AB SWITCHES BUCK REGION
NMOS B
NMOS C
0%
DUTY
V1 ( ≈ 0.7V)
CONTROL
3533 F01
CYCLE
3533 F02
VOLTAGE, V C
Figure 1. Simpli?ed Diagram of Output Switches
Figure 2. Switch Control vs Control Voltage, V C
3533f
8
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相关代理商/技术参数 |
参数描述 |
|---|---|
| LTC3534 | 制造商:LINER 制造商全称:Linear Technology 功能描述:40V, 2A Synchronous Buck-Boost DC/DC |
| LTC3534EDHC#PBF | 功能描述:IC REG BUCK BOOST SYNC ADJ 16DFN 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:2,500 系列:- 类型:降压（降压） 输出类型:固定 输出数:1 输出电压:1.2V，1.5V，1.8V，2.5V 输入电压:2.7 V ~ 20 V PWM 型:- 频率 - 开关:- 电流 - 输出:50mA 同步整流器:是 工作温度:-40°C ~ 125°C 安装类型:表面贴装 封装/外壳:10-TFSOP，10-MSOP（0.118"，3.00mm 宽）裸露焊盘 包装:带卷 (TR) 供应商设备封装:10-MSOP 裸露焊盘 |
| LTC3534EDHC#TRPBF | 功能描述:IC REG BUCK BOOST SYNC ADJ 16DFN 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:2,500 系列:- 类型:降压（降压） 输出类型:固定 输出数:1 输出电压:1.2V，1.5V，1.8V，2.5V 输入电压:2.7 V ~ 20 V PWM 型:- 频率 - 开关:- 电流 - 输出:50mA 同步整流器:是 工作温度:-40°C ~ 125°C 安装类型:表面贴装 封装/外壳:10-TFSOP，10-MSOP（0.118"，3.00mm 宽）裸露焊盘 包装:带卷 (TR) 供应商设备封装:10-MSOP 裸露焊盘 |
| LTC3534EGN#PBF | 功能描述:IC REG BUCK BST SYNC 0.5A 16SSOP 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 |
| LTC3534EGN#TRPBF | 功能描述:IC REG BUCK BST SYNC 0.5A 16SSOP 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:2,500 系列:- 类型:降压（降压） 输出类型:固定 输出数:1 输出电压:1.2V，1.5V，1.8V，2.5V 输入电压:2.7 V ~ 20 V PWM 型:- 频率 - 开关:- 电流 - 输出:50mA 同步整流器:是 工作温度:-40°C ~ 125°C 安装类型:表面贴装 封装/外壳:10-TFSOP，10-MSOP（0.118"，3.00mm 宽）裸露焊盘 包装:带卷 (TR) 供应商设备封装:10-MSOP 裸露焊盘 |
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