参数资料
型号: LT1576CS8-5#PBF
厂商: Linear Technology
文件页数: 25/28页
文件大小: 0K
描述: IC REG BUCK 5V 1.5A 8SOIC
标准包装: 100
类型: 降压(降压)
输出类型: 固定
输出数: 1
输出电压: 5V
输入电压: 5 V ~ 25 V
PWM 型: 电流模式
频率 - 开关: 200kHz
电流 - 输出: 1.5A
同步整流器:
工作温度: 0°C ~ 125°C
安装类型: 表面贴装
封装/外壳: 8-SOIC(0.154",3.90mm 宽)
包装: 管件
供应商设备封装: 8-SOIC
LT1576/LT1576-5
APPLICATIO N S I N FOR M ATIO N
( 5 . 5 ) ( 1 . 5 )
inductoristhereforetypicallybasedonensuringthatpeak
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-
I CONT =
2 2
4 ( 5 . 5 + 5 ) ( 5 . 5 + 5 + 0 . 5 )
= 0 . 38 A
promise value is often chosen that reduces output ripple.
As you can see from the graph, large inductors will not
This says that discontinuous mode can be used and the
minimum inductor needed is found from:
( )( ) = 5 . 6 μ H
? ( )
? 200 ? 10 1 . 5 2
give arbitrarily low ripple, but small inductors 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
L MIN =
?
2 5 0 . 25
3 ?
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:
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-
( V ) ( I )
4 ( ) ( V + V
I CONT =
V IN + V OUT IN OUT + V F
IN P
2 2
)
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-
2 ( V OUT )( I OUT )
( f )( I )
L MIN =
Minimum inductor discontinuous mode:
2
P
Minimum inductor continuous mode:
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.
( ) (
)
2 f V IN + V OUT ? I P ? I OUT ? 1 +
?
) ? ? ? ?
? ?
L MIN =
( V IN )( V OUT )
? ?
? ?
?
(
V OUT + V F
V IN
? ?
For the example above, with maximum load current of
0.25A:
25
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LT1576CS8-5SYNC 功能描述:IC REG BUCK 5V 1.5A 8SOIC RoHS:否 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 开关稳压器 系列:- 标准包装:2,500 系列:- 类型:降压(降压) 输出类型:固定 输出数:1 输出电压:1.2V,1.5V,1.8V,2.5V 输入电压:2.7 V ~ 20 V PWM 型:- 频率 - 开关:- 电流 - 输出:50mA 同步整流器:是 工作温度:-40°C ~ 125°C 安装类型:表面贴装 封装/外壳:10-TFSOP,10-MSOP(0.118",3.00mm 宽)裸露焊盘 包装:带卷 (TR) 供应商设备封装:10-MSOP 裸露焊盘
LT1576CS8-5SYNC#PBF 功能描述:IC REG BUCK 5V 1.5A 8SOIC 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:20 系列:SIMPLE SWITCHER® 类型:降压(降压) 输出类型:固定 输出数:1 输出电压:12V 输入电压:4 V ~ 60 V PWM 型:电压模式 频率 - 开关:52kHz 电流 - 输出:1A 同步整流器:无 工作温度:-40°C ~ 125°C 安装类型:通孔 封装/外壳:16-DIP(0.300",7.62mm) 包装:管件 供应商设备封装:16-DIP 其它名称:*LM2575HVN-12LM2575HVN-12
LT1576CS8-5SYNC#TR 功能描述:IC REG BUCK 5V 1.5A 8SOIC RoHS:否 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 开关稳压器 系列:- 标准包装:2,500 系列:- 类型:降压(降压) 输出类型:固定 输出数:1 输出电压:1.2V,1.5V,1.8V,2.5V 输入电压:2.7 V ~ 20 V PWM 型:- 频率 - 开关:- 电流 - 输出:50mA 同步整流器:是 工作温度:-40°C ~ 125°C 安装类型:表面贴装 封装/外壳:10-TFSOP,10-MSOP(0.118",3.00mm 宽)裸露焊盘 包装:带卷 (TR) 供应商设备封装:10-MSOP 裸露焊盘
LT1576CS8-5SYNC#TRPBF 功能描述:IC REG BUCK 5V 1.5A 8SOIC 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:20 系列:SIMPLE SWITCHER® 类型:降压(降压) 输出类型:固定 输出数:1 输出电压:12V 输入电压:4 V ~ 60 V PWM 型:电压模式 频率 - 开关:52kHz 电流 - 输出:1A 同步整流器:无 工作温度:-40°C ~ 125°C 安装类型:通孔 封装/外壳:16-DIP(0.300",7.62mm) 包装:管件 供应商设备封装:16-DIP 其它名称:*LM2575HVN-12LM2575HVN-12
LT1576CS8-SYNC 功能描述:IC REG BUCK ADJ 1.5A 8SOIC RoHS:否 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 开关稳压器 系列:- 标准包装:2,500 系列:- 类型:升压(升压) 输出类型:可调式 输出数:1 输出电压:1.24 V ~ 30 V 输入电压:1.5 V ~ 12 V PWM 型:电流模式,混合 频率 - 开关:600kHz 电流 - 输出:500mA 同步整流器:无 工作温度:-40°C ~ 85°C 安装类型:表面贴装 封装/外壳:8-SOIC(0.154",3.90mm 宽) 包装:带卷 (TR) 供应商设备封装:8-SOIC