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参数资料
| 型号： | LTC3547BIDDB#PBF |
| 厂商： | LINEAR TECHNOLOGY CORP |
| 元件分类： | 稳压器 |
| 英文描述： | 0.7 A DUAL SWITCHING CONTROLLER, 2700 kHz SWITCHING FREQ-MAX, PDSO8 |
| 封装： | 3 X 2 MM, 0.75 MM HEIGHT, LEAD FREE, PLASTIC, M0-229WECD-1, DFN-8 |
| 文件页数： | 6/16页 |
| 文件大小： | 248K |
| 代理商： | LTC3547BIDDB#PBF |
LTC3547B
14
3547bfb
OUTPUT CURRENT (mA)
30
EFFICIENCY
(%)
90
100
20
10
80
50
70
60
40
0.1
10
100
1000
0
1
VIN = 2.7V
VIN = 3.6V
VIN = 4.2V
VOUT = 1.8V
OUTPUT CURRENT (mA)
30
EFFICIENCY
(%)
90
100
20
10
80
50
70
60
40
0.1
10
100
1000
3547b F04b
0
1
VIN = 2.7V
VIN = 3.6V
VIN = 4.2V
VOUT = 2.5V
APPLICATIO S I FOR ATIO
WU
U
Design Example
As a design example, consider using the LTC3547B in
a portable application with a Li-Ion battery. The battery
provides a VIN ranging from 2.8V to 4.2V. The load on each
channel requires a maximum of 300mA in active mode
and 2mA in standby mode. The output voltages are VOUT1
= 2.5V and VOUT2 = 1.8V.
Start with channel 1. First, calculate the inductor value
for about 40% ripple current (120mA in this example) at
maximum VIN. Using a derivation of Equation 1:
L1
=
2.5V
2.25MHz (120mA)
1
2.5V
4.2V
= 3.75μH
For the inductor, use the closest standard value of 4.7μH.
A 4.7μF capacitor should be more than sufcient for this
output capacitor. As for the input capacitor, a typical value
of CIN = 4.7μF should sufce, as the source impedance of
a Li-Ion battery is very low.
Figure 4a. Design Example Circuit
Figure 4b. Efciency vs Output Current
VIN
RUN2
RUN1
LTC3547B
VFB2
SW2
SW1
VFB1
CF2, 10pF
CF1, 10pF
GND
VIN
2.5V TO 5.5V
VOUT2
1.8V AT 300mA
VOUT1
2.5V AT 300mA
3547b F04a
R3
280k
R1
280k
R4
562k
L2
4.7μH
L1
4.7μH
R2
887k
COUT2
4.7μF
C1
4.7μF
COUT1
4.7μF
C1, C2, C3: TAIYO YUDEN JMK316BJ475ML
L1, L2: MURATA LQH32CN4R7M33
The feedback resistors program the output voltage. To
maintain high efciency at light loads, the current in these
resistors should be kept small. Choosing 2μA with the
0.6V feedback voltage makes R1~300k. A close standard
1% resistor is 280k, using Equation 4.
R2
=
VOUT
0.6
1 R1
= 887k
An optional 10pF feedback capacitor (CF1) may be used
to improve transient response.
Using the same analysis for channel 2 (VOUT2 = 1.8V),
the results are:
L2 = 3.81μH
R3 = 280k
R4 = 560k
Figure 4 shows the complete schematic for this example,
along with the efciency curve and transient response.
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相关代理商/技术参数 |
参数描述 |
|---|---|
| LTC3547EDDB | 制造商:LINER 制造商全称:Linear Technology 功能描述:Dual Monolithic 300mA Synchronous Step-Down Regulator |
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| LTC3547EDDB#TRMPBF | 功能描述:IC REG BUCK SYNC ADJ .3A DL 8DFN 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:250 系列:- 类型:降压（降压） 输出类型:固定 输出数:1 输出电压:1.2V 输入电压:2.05 V ~ 6 V PWM 型:电压模式 频率 - 开关:2MHz 电流 - 输出:500mA 同步整流器:是 工作温度:-40°C ~ 85°C 安装类型:表面贴装 封装/外壳:6-UFDFN 包装:带卷 (TR) 供应商设备封装:6-SON（1.45x1） 产品目录页面:1032 (CN2011-ZH PDF) 其它名称:296-25628-2 |
| LTC3547EDDB#TRPBF | 功能描述:IC REG BUCK SYNC ADJ .3A DL 8DFN 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: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 |
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