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參數(shù)資料
| 型號： | LT3581EMSE#PBF |
| 廠商： | LINEAR TECHNOLOGY CORP |
| 元件分類： | 穩(wěn)壓器 |
| 英文描述： | SWITCHING REGULATOR, PDSO16 |
| 封裝： | LEAD FREE, PLASTIC, MSOP-16 |
| 文件頁數(shù)： | 16/36頁 |
| 文件大?。?/td> | 498K |
| 代理商： | LT3581EMSE#PBF |
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LT3581
3581f
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 three
conditions that limit the minimum inductance: (1) provid-
ing adequate load current, (2) avoidance of subharmonic
oscillations and (3) supplying a minimum ripple current
to avoid false tripping of the current comparator.
Adequate Load Current
Smallvalueinductorsresultinincreasedripplecurrentsand
thus, due to the limited peak switch current, decrease the
average current that can be provided to the load. In order
to provide adequate load current, L should be at least:
L
DC V
V
f
I
V
I
BOOST
IN
CESAT
OSC
PK
OUT
OU
>
(
)
2
|
TT
IN
DUAL
IN
CESAT
OSC
V
or
L
DC V
V
f
>
(
)
η
2
II
V
I
V
I
PK
OUT
IN
OUT
|
η
Boost
Topology
SEPIC
or
Inverting
Topologies
where:
LBOOST = L1 for Boost Topologies (see Figure 5)
LDUAL = L1 = L2 for Coupled Dual Inductor
Topologies (see Figures 6 and 7)
LDUAL = L1 || L2 for Uncoupled Dual Inductor
Topologies (see Figures 6 and 7)
DC
= Switch Duty Cycle (see Power Switch Duty
Cycle section in Appendix)
IPK
= Maximum Peak Switch Current; should not
exceed 3.3A for a combined SW1 + SW2
current, or 1.9A of SW1 current if SW1 is
being used by itself.
η
= Power Conversion Efficiency (typically 88%
for Boost and 75% for Dual Inductor
Topologies at High Currents)
fOSC
= Switching Frequency
IOUT
= Maximum Output Current
appenDix
Negative values of LBOOST or LDUAL indicate that the out-
put load current, IOUT, exceeds the switch current limit
capability of the LT3581.
Avoiding Sub-Harmonic Oscillations
The LT3581’s internal slope compensation circuit will
prevent sub-harmonic oscillations that can occur when
the duty cycle is greater than 50%, provided that the
inductance exceeds a certain minimum value. In applica-
tions that operate with duty cycles greater than 50%, the
inductance must be at least:
L
V
DC
A f
DC
MIN
IN
CESAT
OSC
=
(
)
(
)
(
)
2
1
2 2
1
.
where:
LMIN = L1 for Boost Topologies (see Figure 5)
LMIN = L1 = L2 for Coupled Dual Inductor
Topologies (see Figures 6 and 7)
LMIN = L1 || L2 for Uncoupled Dual Inductor
Topologies (see Figures 6 and 7)
Maximum Inductance
Excessive inductance can reduce ripple current to levels
thataredifficultforthecurrentcomparator(A4intheBlock
Diagram) to cleanly discriminate, causing duty cycle jitter
and/or poor regulation. The maximum inductance can be
calculated by:
L
V
mA
DC
f
MAX
IN
CESAT
OSC
=
350
where:
LMAX = L1 for Boost Topologies (see Figure 5)
LMAX = L1 = L2 for Coupled Dual Inductor
Topologies (see Figures 6 and 7)
LMAX = L1 || L2 for Uncoupled Dual Inductor
Topologies (see Figures 6 and 7)
相關PDF資料 |
PDF描述 |
|---|---|
| LT3581EMSE#TRPBF | SWITCHING REGULATOR, PDSO16 |
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| LT3581IMSE#TRPBF | SWITCHING REGULATOR, PDSO16 |
| LT3581IMSE#PBF | SWITCHING REGULATOR, PDSO16 |
| LT3581IDE#PBF | SWITCHING REGULATOR, PDSO14 |
相關代理商/技術參數(shù) |
參數(shù)描述 |
|---|---|
| LT3581EMSE-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 |
| LT3581HDE#PBF | 制造商:Linear Technology 功能描述:IC REG MULTI CONFIG ADJ 14DFN |
| LT3581HDE#TRPBF | 制造商:Linear Technology 功能描述:IC REG MULTI CONFIG ADJ 14DFN |
| LT3581IDE#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: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 |
| LT3581IDE#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 |
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