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參數資料
| 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： | 27/28頁 |
| 文件大小： | 289K |
| 代理商： | LT3580MPMS8E#TRPBF |
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LT3580
8
3580fg
Setting Output Voltage
The output voltage is set by connecting a resistor (RFB)
from VOUT to the FB pin. RFB is determined from the
following equation:
R
FB =
|V
OUT VFB |
83.3A
where VFB is 1.215V (typical) for non-inverting topologies
(i.e., boost and SEPIC regulators) and 5mV (typical) for
inverting topologies (see the Electrical Characteristics).
Power Switch Duty Cycle
In order to maintain loop stability and deliver adequate
current to the load, the power NPN (Q1 in the Block Dia-
gram) cannot remain “on” for 100% of each clock cycle.
The maximum allowable duty cycle is given by:
DC
MAX =
(T
P Min Off Time)
T
P
100%
where TP is the clock period and Min Off Time (found in
the Electrical Characteristics) is typically 60ns.
The application should be designed so that the operating
duty cycle does not exceed DCMAX.
Duty cycle equations for several common topologies are
given below, where VD is the diode forward voltage drop
and VCESAT is typically 300mV at 1.5A.
For the boost topology:
DC
V
OUT VIN + VD
V
OUT + VD VCESAT
For the SEPIC or dual inductor inverting topology (see
Figures 1 and 2):
DC
V
D + |VOUT |
V
IN + |VOUT | + VD VCESAT
The LT3580 can be used in configurations where the duty
cycle is higher than DCMAX, but it must be operated in the
discontinuous conduction mode so that the effective duty
cycle is reduced.
APPLICATIONS INFORMATION
Inductor Selection
General Guidelines: The high frequency operation of the
LT3580 allows for the use of small surface mount inductors.
For high efficiency, choose inductors with high frequency
core material, such as ferrite, to reduce core losses. To
improve efficiency, choose inductors with more volume
for a given inductance. The inductor should have low
DCR (copper wire resistance) to reduce I2R losses, and
must be able to handle the peak inductor current without
saturating. Note that in some applications, the current
handling requirements of the inductor can be lower, such
as in the SEPIC topology, where each inductor only carries
a fraction of the total switch current. Molded chokes or chip
inductors usually do not have enough core area to sup-
port peak inductor currents in the 2A to 3A range. To
minimize radiated noise, use a toroidal or shielded inductor.
Note that the inductance of shielded types will drop more
as current increases, and will saturate more easily. See
Table 1 for a list of inductor manufacturers. Thorough lab
evaluation is recommended to verify that the following
guidelines properly suit the final application.
Table 1.Inductor Manufacturers
Coilcraft
DO3316P, MSS7341 and LPS4018
Series
www.coilcraft.com
Coiltronics DR, LD and CD Series
www.coiltronics.com
Murata
LQH55D and LQH66S Series
www.murata.com
Sumida
CDRH5D18B/HP, CDR6D23MN,
CDRH6D26/HP, CDRH6D28,
CDR7D28MN and CDRH105R Series
www.sumida.com
TDK
RLF7030 and VLCF4020 Series
www.tdk.com
Würth
WE-PD and WE-PD2 Series
www.we-online.com
Minimum Inductance: Although there can be a tradeoff with
efficiency, it is often desirable to minimize board space by
choosing smaller inductors. When choosing an inductor,
there are two conditions that limit the minimum inductance;
(1) providing adequate load current, and (2) avoidance of
subharmonic oscillation. Choose an inductance that is high
enough to meet both of these requirements.
Adequate Load Current : Small value inductors result in
increased ripple currents and thus, due to the limited peak
switch current, decrease the average current that can be
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相關代理商/技術參數 |
參數描述 |
|---|---|
| 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: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: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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