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| 型号： | LTC3569EFE#PBF |
| 厂商： | LINEAR TECHNOLOGY CORP |
| 元件分类： | 稳压器 |
| 英文描述： | 2.5 A SWITCHING REGULATOR, 3000 kHz SWITCHING FREQ-MAX, PDSO16 |
| 封装： | 4.40 MM, LEAD FREE, PLASTIC, TSSOP-16 |
| 文件页数： | 14/26页 |
| 文件大小： | 468K |
| 代理商： | LTC3569EFE#PBF |
LTC3569
21
3569fd
APPLICATIONS INFORMATION
Figure 8. Dual Programmable Buck DC/DC Regulators
Design Example 4: Dual 1A Bucks
VOUT = 1.6V, Burst Mode Operation
ILOAD (mA)
EFFICIENCY
(%)
3569 F08b
100
90
80
70
60
50
40
0.1
1
1000
10000
100
10
BUCK 1
BUCK 2, 3
VIN = 2.5V
VIN = 5.5V
3569 F08
SVIN PVIN SW1
PGND
SGND
SW2
SW3
PGOOD
FB1
EN1
EN2
EN3
MODE
RT
FB2
FB3
22F
VIN 2.5V TO 5.5V
2.2H
10F
20pF
10F
2.2H
210k
162k
210k
162k
OUT1 800mA
1.2V STANDBY
1.6V ACTIVE
OUT2 800mA
1.2V STANDBY
1.6V ACTIVE
LTC3569
511k
VIN
DIGITAL
CONTROL
Design Example 4: Dual Programmable Bucks
In this example consider two buck regulators operating
from a 2.5V to 5.5V unregulated supply that are required
togeneratetwoindependentlyprogrammablesuppliesthat
must step from 1.2V in standby up to 1.6V when active,
withamaximumloadcurrentof0.8Awhenactiveand1mA
in standby. Furthermore, when switching between active
and standby, the load voltage should not droop.
Buck 1 is selected for the first regulator, and buck 3 is
configured as a slave power stage in parallel with buck 2
by pulling FB3 up to VIN to obtain the required current level
for the second regulator. Burst Mode operation is selected
to achieve high efficiency during standby operation. The
internal2.25MHzclockfrequencyisselected,asitsatisfies
the minimum on-time requirement. Next, two reference
voltages are selected to match the ratio of the active to
standby voltages: 1.6V/1.2V = 1.3333. There are three
reference value ratios that match this ratio: 0.8V and 0.6V,
0.7V and 0.525V, and 0.6V and 0.45V. As the load cannot
tolerate a voltage droop when switching from standby to
active,the0.7Vand0.525Vreferencesareselectedtomatch
the ratio of output voltages. With this ratio, the buck does
not need to be shutdown as it would if the full-scale 0.8V
referencelevelwaschosen.TheresistorsshowninFigure8
are selected to obtain the nearest feedback ratio from
standard 1% resistors. Calculating the inductor values
for 30% ripple current at maximum SVIN:
L = 1.6V/(2.25MHz240mA)(1–1.6V/5.5V) ≈ 2.2H.
The output capacitor values are selected as the nearest
standard value to obtain 5% voltage droop at maximum
load current step.
COUT = 2.5800mA/(2.25MHz90mV) ≈ 10F.
Select an output capacitor with an ESR of less than 50m
to obtain an output voltage ripple of less than 30mV.
Finally select an input capacitor rated for the worst-case
short-circuit ripple current of 2 IPK/√3 ≈ 2.5A, when both
outputs are shorted to GND.
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相关代理商/技术参数 |
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|---|---|
| LTC3569EFE-TRPBF | 制造商:LINER 制造商全称:Linear Technology 功能描述:Triple Buck Regulator With 1.2A and Two 600mA Outputs and Individual Programmable References |
| LTC3569EUD#PBF | 功能描述:IC REG BUCK SYNC ADJ TRPL 20QFN 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 |
| LTC3569EUD#TRPBF | 功能描述:IC REG BUCK SYNC ADJ TRPL 20QFN 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: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 |
| LTC3569EUDC#PBF | 功能描述:IC REG BUCK SYNC ADJ TRPL 20QFN 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: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 |
| LTC3569EUDC#TRPBF | 功能描述:IC REG BUCK SYNC ADJ TRPL 20QFN 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: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 |
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