參數(shù)資料
型號(hào)： LT1576
廠(chǎng)商： Linear Technology Corporation
英文描述： 1.5A, 200kHz Step-Down Switching Regulator(可調(diào)輸出，1.5A, 200kHz，步降開(kāi)關(guān)穩(wěn)壓器)
中文描述： 1.5A的，200kHz降壓型開(kāi)關(guān)穩(wěn)壓器（可調(diào)輸出，1.5A的，200kHz的，步降開(kāi)關(guān)穩(wěn)壓器）
文件頁(yè)數(shù)： 25/28頁(yè)
文件大?。?/td> 290K
代理商： LT1576
25
LT1576/LT1576-5
APPLICATIO
S I
FOR
ATIO
U
inductor is therefore typically based on ensuring that peak
switch current rating is not exceeded. This gives the
lowest value of inductance that can be used, but in some
cases (lower output load currents) it may give a value that
creates unnecessarily high output ripple voltage. A com-
promise value is often chosen that reduces output ripple.
As you can see from the graph, largeinductors will not
give arbitrarily low ripple, but smallinductors can give
high ripple.
The difficulty in calculating the minimum inductor size
needed is that you must first know whether the switcher
will be in continuous or discontinuous mode at the critical
point where switch current is 1.5A. The first step is to use
the following formula to calculate the load current where
the switcher must use continuous mode. If your load
current is less than this, use the discontinuous mode
formula to calculate minimum inductor needed. If load
current is higher, use the continuous mode formula.
Output current where continuous mode is needed:
W
U
U
I
A
CONT
=
( ) ( )
)
(
+ +
(
)
=
4 5 5 5 5 5 5 0 5
.
0 38
2
2
.
.
This says that discontinuous mode can be used and the
minimum inductor needed is found from:
( )(
L
H
MIN
=
)
( )
=
2 5 0 25
200 10
1 5
.
5 6
3
2
.
In practice, the inductor should be increased by about 30%
over the calculated minimum to handle losses and varia-
tions in value. This suggests a minimum inductor of 7.3
μ
H
for this application, but looking at the ripple voltage chart
shows that output ripple voltage could be reduced by a fac-
tor of two by using a 30
μ
H inductor. There is no rule of thumb
here to make a final decision. If modest ripple is needed and
the larger inductor does the trick, go for it. If ripple is non-
critical use the smaller inductor. If ripple is extremely criti-
cal, a second filter may have to be added in any case, and
the lower value of inductance can be used. Keep in mind
that the output capacitor is the other critical factor in deter-
mining output ripple voltage. Ripple shown on the graph
(Figure 16) is with a capacitor’s ESR of 0.1
. This is
rea-
sonable for AVX type TPS “D” or “E” size surface mount solid
tantalum capacitors, but the final capacitor chosen must be
looked at carefully for ESR characteristics.
I
V
I
V
V
V
V
V
CONT
IN
)
IN
OUT
IN
OUT
F
=
( ) ( )
(
+
(
+
+
)
2
2
4
Minimum inductor discontinuous mode:
=
(
( )( )
L
V
I
f I
MIN
OUT
OUT
2
P
)(
)
2
Minimum inductor continuous mode:
L
V
V
f V
( )
V
I
I
V
V
V
MIN
IN
OUT
IN
OUT
P
OUT
OUT
F
IN
=
( )(
)
+
(
)
+
+
(
)
2
1
For the example above, with maximum load current of
0.25A:
相關(guān)PDF資料
PDF描述
LT1578-2.5 RADIATION HARDENED HIGH EFFICIENCY, 5 AMP SWITCHING REGULATORS
LT1578IS8 RADIATION HARDENED HIGH EFFICIENCY, 5 AMP SWITCHING REGULATORS
LT1578IS8-2.5 RADIATION HARDENED HIGH EFFICIENCY, 5 AMP SWITCHING REGULATORS
LT1578C CAP 22UF 50V ELECT TG SMD
LT1578CS8 CAP 47UF 50V ELECT TG SMD
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
LT-1576-111-012 制造商:Carling Technologies 功能描述:LT-SERIES TOGGLE SWITCH - Bulk
LT1576-5 制造商:LINER 制造商全稱(chēng):Linear Technology 功能描述:1.5A, 200kHz Step-Down Switching Regulator
LT1576C 制造商:LINER 制造商全稱(chēng):Linear Technology 功能描述:1.5A, 200kHz Step-Down Switching Regulator
LT1576CS8 功能描述:IC REG BUCK ADJ 1.5A 8SOIC RoHS:否 類(lèi)別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - DC DC 開(kāi)關(guān)穩(wěn)壓器 系列:- 設(shè)計(jì)資源:Design Support Tool 標(biāo)準(zhǔn)包裝:1 系列:- 類(lèi)型:升壓（升壓） 輸出類(lèi)型:固定 輸出數(shù):1 輸出電壓:3V 輸入電壓:0.75 V ~ 2 V PWM 型:- 頻率 - 開(kāi)關(guān):- 電流 - 輸出:100mA 同步整流器:是 工作溫度:-40°C ~ 85°C 安裝類(lèi)型:表面貼裝 封裝/外殼:SOT-23-5 細(xì)型，TSOT-23-5 包裝:剪切帶 (CT) 供應(yīng)商設(shè)備封裝:TSOT-23-5 其它名稱(chēng):AS1323-BTTT-30CT
LT1576CS8#PBF 功能描述:IC REG BUCK ADJ 1.5A 8SOIC RoHS:是 類(lèi)別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - DC DC 開(kāi)關(guān)穩(wěn)壓器 系列:- 標(biāo)準(zhǔn)包裝:250 系列:- 類(lèi)型:降壓（降壓） 輸出類(lèi)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(kāi)關(guān):2MHz 電流 - 輸出:500mA 同步整流器:是 工作溫度:-40°C ~ 85°C 安裝類(lèi)型:表面貼裝 封裝/外殼:6-UFDFN 包裝:帶卷 (TR) 供應(yīng)商設(shè)備封裝:6-SON（1.45x1） 產(chǎn)品目錄頁(yè)面:1032 (CN2011-ZH PDF) 其它名稱(chēng):296-25628-2
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