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参数资料
| 型号： | LTC3546EUFD |
| 厂商： | LINEAR TECHNOLOGY CORP |
| 元件分类： | 稳压器 |
| 英文描述： | DUAL SWITCHING CONTROLLER, 4000 kHz SWITCHING FREQ-MAX, PQCC28 |
| 封装： | 4 X 5 MM, PLASTIC, MO-220, QFN-28 |
| 文件页数： | 6/28页 |
| 文件大小： | 356K |
| 代理商： | LTC3546EUFD |
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LTC3546
14
3546fb
APPLICATIONS INFORMATION
A general LTC3546 application circuit is shown in Figure 7.
External component selection is driven by the load require-
ment, and begins with the selection of the inductors L1,
and L2. Once L1 and L2 are chosen, CIN, COUT1, and COUT2
can be selected.
Operating Frequency
Selection of the operating frequency is a trade-off between
efciency and component size. High frequency operation
allows the use of smaller inductor and capacitor values.
Operation at lower frequencies improves efciency by
reducing internal gate charge losses but requires larger
inductance values and/or capacitance to maintain low
output ripple voltage.
The operating frequency, fO, of the LTC3546 is determined
by pulling the FREQ pin to VIN, for 2.25MHz operation, by
connecting an external resistor from FREQ to ground, or
by driving an external clock signal into SYNC/MODE.
When using an external resistor to set the oscillator fre-
quency use the following equation:
R
T =
2.5110
11
f
O
Ω
() –20kΩ
for 0.75MHz ≤ fO ≤ 4MHz. Or use Figure 1 to select the
value for RT.
The maximum operating frequency is also constrained
by the minimum on-time (typically 70ns) and duty cycle,
especially when forced continuous mode is selected.
Assuming a worst-case minimum on-time of 150ns, this
can be calculated as:
fO(MAX) 6.67
VOUT
VIN(MAX)
MHz
()
The minimum frequency is limited by leakage and noise
coupling due to the large resistance of RT.
Inductor Selection
Although the inductor does not inuence the operat-
ing frequency, the inductor value has a direct effect on
ripple current. The inductor ripple current ΔIL decreases
with higher inductance and increases with higher VIN or
VOUT.
IL =
VOUT
fO L
1
VOUT
VIN
Accepting larger values of ΔIL allows the use of low induc-
tances, but results in higher output voltage ripple, greater
core losses, and lower output current capability.
A reasonable starting point for setting ripple current is ΔIL
= 0.35ILOAD(MAX),whereILOAD(MAX)isthemaximumoutput
current. The largest ripple ΔIL occurs at the maximum
input voltage. To guarantee that the ripple current stays
below a specied maximum, the inductor value should be
chosen according to the following equation:
L
VOUT
fO IL
1
VOUT
VIN(MAX)
Figure 1. Frequency vs RT
FREQUENCY (MHz)
0
R
T(kΩ)
500
50
450
350
250
150
400
300
200
100
0
2.5
1.5
3.5
3546 F01
4.5
2.0
4.0
1.0
3.0
0.5
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相关代理商/技术参数 |
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| LTC3546EUFD#PBF | 功能描述:IC REG BUCK SYNC ADJ 1A/2A 28QFN RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 开关稳压器 系列:- 产品培训模块:MIC23xxx HyperLight Load™ Regulators 标准包装:5,000 系列:HyperLight Load® 类型:降压（降压） 输出类型:固定 输出数:1 输出电压:1.8V 输入电压:2.7 V ~ 5.5 V PWM 型:混合物 频率 - 开关:4MHz 电流 - 输出:2A 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:8-VFDFN 裸露焊盘，8-MLF? 包装:带卷 (TR) 供应商设备封装:8-MLF?（2x2） 产品目录页面:1094 (CN2011-ZH PDF) 其它名称:576-3303-2 |
| LTC3546EUFD#TRPBF | 功能描述:IC REG BUCK SYNC ADJ 1A/2A 28QFN 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 |
| LTC3546EUFDPBF | 制造商:LINER 制造商全称:Linear Technology 功能描述:Dual Synchronous, 3A/1A or 2A/2A Confi gurable Step-Down DC/DC Regulator |
| LTC3546EUFDTRPBF | 制造商:LINER 制造商全称:Linear Technology 功能描述:Dual Synchronous, 3A/1A or 2A/2A Confi gurable Step-Down DC/DC Regulator |
| LTC3546IFE#PBF | 功能描述:IC REG BUCK SYNC ADJ DL 28TSSOP 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 |
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