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参数资料
| 型号： | LT1912EMSE#PBF |
| 厂商： | LINEAR TECHNOLOGY CORP |
| 元件分类： | 稳压器 |
| 英文描述： | 4.2 A SWITCHING REGULATOR, 240 kHz SWITCHING FREQ-MAX, PDSO10 |
| 封装： | LEAD FREE, PLASTIC, MSOP-10 |
| 文件页数： | 7/24页 |
| 文件大小： | 365K |
| 代理商： | LT1912EMSE#PBF |
LT1912
15
1912fa
Shorted and Reversed Input Protection
If the inductor is chosen so that it won’t saturate exces-
sively, an LT1912 buck regulator will tolerate a shorted
output. There is another situation to consider in systems
where the output will be held high when the input to the
LT1912 is absent. This may occur in battery charging ap-
plications or in battery backup systems where a battery
or some other supply is diode OR-ed with the LT1912’s
output. If the VIN pin is allowed to float and the RUN/SS
pin is held high (either by a logic signal or because it is
tied to VIN), then the LT1912’s internal circuitry will pull
its quiescent current through its SW pin. This is fine if
your system can tolerate a few mA in this state. If you
ground the RUN/SS pin, the SW pin current will drop to
essentially zero. However, if the VIN pin is grounded while
the output is held high, then parasitic diodes inside the
LT1912 can pull large currents from the output through
the SW pin and the VIN pin. Figure 7 shows a circuit that
will run only when the input voltage is present and that
protects against a shorted or reversed input.
PCB Layout
For proper operation and minimum EMI, care must be
taken during printed circuit board layout. Figure 8 shows
the recommended component placement with trace,
ground plane and via locations. Note that large, switched
currents flow in the LT1912’s VIN and SW pins, the catch
diode (D1) and the input capacitor (C1). The loop formed
bythesecomponentsshouldbeassmallaspossible.These
components, along with the inductor and output capacitor,
should be placed on the same side of the circuit board,
and their connections should be made on that layer. Place
a local, unbroken ground plane below these components.
Figure 5. The Minimum Input Voltage Depends on
Output Voltage, Load Current and Boost Circuit
1912 F05
LOAD CURRENT (A)
1
INPUT
VOL
TAGE
(V)
4.0
4.5
5.0
10000
3.5
3.0
2.0
10
100
1000
1
10000
10
100
1000
2.5
6.0
5.5 TO START
(WORST CASE)
TO RUN
LOAD CURRENT (A)
INPUT
VOL
TAGE
(V)
5.0
6.0
7.0
4.0
2.0
3.0
8.0
TO RUN
VOUT = 3.3V
TA = 25°C
L = 8.2H
f = 500kHz
VOUT = 5V
TA = 25°C
L = 8.2H
f = 500kHz
TO START
(WORST CASE)
Figure 6. To Soft-Start the LT1912, Add a Resisitor
and Capacitor to the RUN/SS Pin
1912 F06
IL
1A/DIV
VRUN/SS
2V/DIV
VOUT
2V/DIV
RUN/SS
GND
RUN
15k
0.22F
2ms/DIV
Figure 7. Diode D4 Prevents a Shorted Input from
Discharging a Backup Battery Tied to the Output. It Also
Protects the Circuit from a Reversed Input. The LT1912
Runs Only When the Input is Present
VIN
BOOST
GND FB
RUN/SS
VC
SW
D4
MBRS140
VIN
LT1912
1912 F07
VOUT
BACKUP
APPLICATIONS INFORMATION
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相关代理商/技术参数 |
参数描述 |
|---|---|
| LT1912EMSE-TRPBF | 制造商:LINER 制造商全称:Linear Technology 功能描述:36V, 2A, 500kHz Step-Down Switching Regulator |
| LT1913 | 制造商:LINER 制造商全称:Linear Technology 功能描述:25V, 3.5A, 2.4MHz Step-Down Switching Regulator |
| LT1913EDD#PBF | 功能描述:IC REG BUCK ADJ 3.5A 10DFN 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 |
| LT1913EDD#TRPBF | 功能描述:IC REG BUCK ADJ 3.5A 10DFN 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 |
| LT1913EDD-PBF | 制造商:LINER 制造商全称:Linear Technology 功能描述:25V, 3.5A, 2.4MHz Step-Down Switching Regulator |
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