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參數(shù)資料
| 型號： | LT3580MPMS8E#TRPBF |
| 廠商： | LINEAR TECHNOLOGY CORP |
| 元件分類： | 穩(wěn)壓器 |
| 英文描述： | 2.8 A SWITCHING REGULATOR, 2500 kHz SWITCHING FREQ-MAX, PDSO8 |
| 封裝： | LEAD FREE, PLASTIC, MSOP-8 |
| 文件頁數(shù)： | 26/28頁 |
| 文件大?。?/td> | 289K |
| 代理商： | LT3580MPMS8E#TRPBF |
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LT3580
7
3580fg
OPERATION
Figure 1. SEPIC Topology Allows for the Input to Span
the Output Voltage. Coupled or Uncoupled Inductors
Can Be Used. Follow Noted Phasing if Coupled
Figure 2. Dual Inductor Inverting Topology Results in
Low Output Ripple. Coupled or Uncoupled Inductors
Can Be Used. Follow Noted Phasing if Coupled
D1
SHUTDOWN
L2
C3
L1
R1
VIN > VOUT
OR
VIN = VOUT
OR
VIN < VOUT
VOUT
VIN
SW
3580 F01
LT3580
RT
RC
C2
SHDN
GND
FB
VC
SYNC
SS
RT
CC
CSS
C1
+
D1
SHUTDOWN
C3
L1
R1
VIN
VOUT
VIN
SW
3580 F02
LT3580
RT
RC
C2
SHDN
GND
FB
VC
SYNC
SS
RT
CC
CSS
C1
L2
+
SEPIC Topology
The LT3580 can be configured as a SEPIC (single-ended
primary inductance converter). This topology allows for
the input to be higher, equal, or lower then the desired
output voltage. Output disconnect is inherently built into
the SEPIC topology, meaning no DC path exists between the
input and output. This is useful for applications requiring
the output to be disconnected from the input source when
the circuit is in shutdown.
Inverting Topology
The LT3580 can also work in a dual inductor inverting
topology. The part’s unique feedback pin allows for the
inverting topology to be built by simply changing the
connection of external components. This solution results
in very low output voltage ripple due to inductor L2 in
series with the output. Abrupt changes in output capacitor
current are eliminated because the output inductor deliv-
ers current to the output during both the off-time and the
on-time of the LT3580 switch.
Start-Up Operation
Several functions are provided to enable a very clean
start-up for the LT3580.
First, the SHDN pin voltage is monitored by an internal
voltage reference to give a precise turn-on voltage level.
An external resistor (or resistor divider) can be connected
from the input power supply to the SHDN pin to provide
a user-programmable undervoltage lockout function.
Second, the soft-start circuitry provides for a gradual
ramp-up of the switch current. When the part is brought
out of shutdown, the external SS capacitor is first
discharged (providing protection against SHDN pin
glitches and slow ramping), then an integrated 275k
resistor pulls the SS pin up to ~2.2V. By connecting an
external capacitor to the SS pin, the voltage ramp rate
on the pin can be set. Typical values for the soft-start
capacitor range from 100nF to 1μF.
Finally, the frequency foldback circuit reduces the
switching frequency when the FB pin is in a nominal range
of 350mV to 900mV. This feature reduces the minimum
duty cycle that the part can achieve thus allowing better
control of the switch current during start-up. When the
FB voltage is pulled outside of this range, the switching
frequency returns to normal.
Current Limit and Thermal Shutdown Operation
The LT3580 has a current limit circuit not shown in the
Block Diagram. The switch current is consistently moni-
tored and not allowed to exceed the maximum switch
current at a given duty cycle (see the Electrical Charac-
teristics table). If the switch current reaches this value,
the SR latch (SR1) is reset regardless of the state of the
comparator (A1/A2). Also not shown in the Block Diagram
is the thermal shutdown circuit. If the temperature of the
part exceeds approximately 165°C, the SR2 latch is set
regardless of the state of the comparator (A1/A2). A full
soft-start cycle will then be initiated. The current limit and
thermal shutdown circuits protect the power switch as well
as the external components connected to the LT3580.
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相關代理商/技術參數(shù) |
參數(shù)描述 |
|---|---|
| LT3581 | 制造商:LINER 制造商全稱:Linear Technology 功能描述:3.3A Boost/Inverting DC/DC Converter with Fault Protection |
| LT3581EDE#PBF | 功能描述:IC REG MULTI CONFIG ADJ 14DFN RoHS:是 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - DC DC 開關穩(wěn)壓器 系列:- 標準包裝:250 系列:- 類型:降壓（降壓） 輸出類型:固定 輸出數(shù):1 輸出電壓:1.2V 輸入電壓:2.05 V ~ 6 V PWM 型:電壓模式 頻率 - 開關:2MHz 電流 - 輸出:500mA 同步整流器:是 工作溫度:-40°C ~ 85°C 安裝類型:表面貼裝 封裝/外殼:6-UFDFN 包裝:帶卷 (TR) 供應商設備封裝:6-SON（1.45x1） 產品目錄頁面:1032 (CN2011-ZH PDF) 其它名稱:296-25628-2 |
| LT3581EDE#TRPBF | 功能描述:IC REG MULTI CONFIG ADJ 14DFN RoHS:是 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - DC DC 開關穩(wěn)壓器 系列:- 標準包裝:2,500 系列:- 類型:降壓（降壓） 輸出類型:固定 輸出數(shù):1 輸出電壓:1.2V，1.5V，1.8V，2.5V 輸入電壓:2.7 V ~ 20 V PWM 型:- 頻率 - 開關:- 電流 - 輸出:50mA 同步整流器:是 工作溫度:-40°C ~ 125°C 安裝類型:表面貼裝 封裝/外殼:10-TFSOP，10-MSOP（0.118"，3.00mm 寬）裸露焊盤 包裝:帶卷 (TR) 供應商設備封裝:10-MSOP 裸露焊盤 |
| LT3581EDE-PBF | 制造商:LINER 制造商全稱:Linear Technology 功能描述:3.3A Boost/Inverting DC/DC Converter with Fault Protection |
| LT3581EDE-TRPBF | 制造商:LINER 制造商全稱:Linear Technology 功能描述:3.3A Boost/Inverting DC/DC Converter with Fault Protection |
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