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参数资料
| 型号： | LTC3569EUDC#TRPBF |
| 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, PQCC20 |
| 封装： | 3 X 4 MM, LEAD FREE, PLASTIC, QFN-20 |
| 文件页数： | 13/26页 |
| 文件大小： | 468K |
| 代理商： | LTC3569EUDC#TRPBF |
LTC3569
20
3569fd
APPLICATIONS INFORMATION
Figure 7. Dual Programmable Buck DC/DC Regulators: 1200mA, 1200mA
3569 F07a
SVIN PVIN SW1
PGND
SGND
SW2
SW3
PGOOD
FB1
EN1
EN2
EN3
MODE
RT
FB2
FB3
22F
VIN 2.5V TO 5.5V
1.5H
15F
20pF
15F
1.5H
294k
210k
294k
210k
OUT1 1200mA
1.2V STANDBY
1.8V ACTIVE
OUT2 1200mA
1.2V STANDBY
1.8V ACTIVE
LTC3569
511k
VIN
DIGITAL
CONTROL
Design Example 3: Soft-Start to Standby (1.2V)
Design Example 3: 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 1.8V when active,
with a maximum load current of 1.2A when active and
1mA in standby. Additionally, this application anticipates
possible output short circuits, and is required to operate
without damage in such a situation.
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: 1.8V/1.2V = 1.5. The 0.75V and 0.5V
reference levels mach this ratio. The resistors shown in
Figure 7 are selected to obtain the correct feedback ratio
fromstandard1%resistors.Calculatingtheinductorvalues
for 30% ripple current at maximum SVIN:
L = 1.8V/(2.25MHz360mA)(1–1.8V/5.5V)= 1.5H.
The output capacitor values are selected as the nearest
standard value to obtain 5% voltage droop at maximum
load current step.
COUT = 2.51200mA/(2.25MHz90mV) ≈ 15F.
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.
CH1
OUT1
CH3
PGOOD
CH2
OUT2
CH4
EN1 = EN2
200s/DIV
3569 F07b
500mV/DIV
2V/DIV
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相关代理商/技术参数 |
参数描述 |
|---|---|
| LTC3569EUD-PBF | 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-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 |
| LTC3569IFE#PBF | 功能描述:IC REG BUCK SYNC ADJ 16TSSOP RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 开关稳压器 系列:- 设计资源:Design Support Tool 标准包装:1 系列:- 类型:升压（升压） 输出类型:固定 输出数:1 输出电压:3V 输入电压:0.75 V ~ 2 V PWM 型:- 频率 - 开关:- 电流 - 输出:100mA 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:SOT-23-5 细型，TSOT-23-5 包装:剪切带 (CT) 供应商设备封装:TSOT-23-5 其它名称:AS1323-BTTT-30CT |
| LTC3569IFE#TRPBF | 功能描述:IC REG BUCK SYNC ADJ 16TSSOP RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 开关稳压器 系列:- 设计资源:Design Support Tool 标准包装:1 系列:- 类型:升压（升压） 输出类型:固定 输出数:1 输出电压:3V 输入电压:0.75 V ~ 2 V PWM 型:- 频率 - 开关:- 电流 - 输出:100mA 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:SOT-23-5 细型，TSOT-23-5 包装:剪切带 (CT) 供应商设备封装:TSOT-23-5 其它名称:AS1323-BTTT-30CT |
| LTC3569IFE-PBF | 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 |
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