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参数资料
| 型号： | LTC3442EDE#TRPBF |
| 厂商： | Linear Technology |
| 文件页数： | 14/20页 |
| 文件大小： | 0K |
| 描述： | IC REG BUCK BOOST SYNC ADJ 12DFN |
| 标准包装： | 2,500 |
| 类型： | 降压（降压），升压（升压） |
| 输出类型： | 可调式 |
| 输出数： | 1 |
| 输出电压： | 2.4 V ~ 5.25 V |
| 输入电压： | 2.4 V ~ 5.5 V |
| PWM 型： | Burst Mode? |
| 频率 - 开关： | 300kHz ~ 2MHz |
| 电流 - 输出： | 1.2A |
| 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： | 12-WFDFN 裸露焊盘 |
| 包装： | 带卷 (TR) |
| 供应商设备封装： | 12-DFN（4x3） |
LTC3442
APPLICATIONS INFORMATION
f FILTER — POLE =
Hz
f FILTER — POLE =
V IN
f FILTER — ZERO =
Hz
f RHPZ =
V IN2
2 ? π ? I OUT ? L ? V OUT
OptionalSchottkyDiodes
The Schottky diodes across the synchronous switches?B
and D are not required (V OUT < 4.3V), but provide a lower
drop during the break-before-make time (typically 15ns)
improving efficiency. Use a surface mount Schottky diode
such as an MBRM120T3 or equivalent. Do not use ordi-
nary rectifier diodes, since the slow recovery times will
compromise efficiency. For applications with an output
voltage above 4.3V, a Schottky diode is required from
SW2 to V OUT .
Output Voltage < 2.4V
The LTC3442 can operate as a buck converter with out-
put voltages as low as 0.4V. The part is specified at 2.4V
minimum to allow operation without the requirement of a
Schottky diode. Synchronous switch D is powered from
V OUT and the R DS(ON) will increase at low output voltages,
therefore a Schottky diode is required from SW2 to V OUT
to provide the conduction path to the output. Note that
Burst Mode operation is inhibited at output voltages below
1.6V typical.
Output Voltage > 4.3V
A Schottky diode from SW2 to V OUT is required for output
voltages over 4.3V. The diode must be located as close to
the pins as possible in order to reduce the peak voltage
on SW2 due to the parasitic lead and trace inductance.
Input Voltage > 4.5V
For applications with input voltages above 4.5V which
could exhibit an overload or short-circuit condition, a
2Ω/1nF series snubber is required between SW1 and GND.
A Schottky diode from SW1 to V IN should also be added
as close to the pins as possible. For the higher input volt-
ages, V IN bypassing becomes more critical; therefore, a
ceramic bypass capacitor as close to the V IN and SGND
pins as possible is also required.
Operating Frequency Selection
Higher operating frequencies allow the use of a smaller
inductor and smaller input and output filter capaci-
tors, thus reducing board area and component height.
However, higher operating frequencies also increase the
IC’s total quiescent current due to the gate charge of the
four switches, as given by:
Buck: Iq = (0.8 ? V IN ? f) mA
Boost: Iq = [0.4 ? ( V IN + V OUT ) ? f] mA
Buck/Boost: Iq = [f ? (1.2 ? V IN + 0.4 ? V OUT )] mA
where f = switching frequency in MHz. Therefore frequency
selection is a compromise between the optimal efficiency
and the smallest solution size.
Closing the Feedback Loop
The LTC3442 incorporates voltage mode PWM control. The
control to output gain varies with operation region (buck,
boost, buck/boost), but is usually no greater than 15. The
output filter exhibits a double pole response, as given by:
1
2 ? π ? L ? C OUT
(in buck mode)
Hz
2 ? V OUT ? π ? L ? C OUT
(in boost mode)
where L is in henries and C OUT is in farads.
The output filter zero is given by:
1
2 ? π ? R ESR ? C OUT
where R ESR is the equivalent series resistance of the
output capacitor.
A troublesome feature in boost mode is the right-half plane
zero (RHP), given by:
Hz
The loop gain is typically rolled off before the RHP zero
frequency.
3442fb
14
For more information www.linear.com/LTC3442
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相关代理商/技术参数 |
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| LTC3443 | 制造商:LINER 制造商全称:Linear Technology 功能描述:High Current Micropower 600kHz Synchronous Buck-Boost DC/DC Converter |
| LTC3443EDE | 功能描述:IC REG BUCK BOOST SYNC ADJ 12DFN 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 |
| LTC3443EDE#PBF | 功能描述:IC REG BUCK BOOST SYNC ADJ 12DFN 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 |
| LTC3443EDE#TR | 功能描述:IC REG BUCK BOOST SYNC ADJ 12DFN 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 |
| LTC3443EDE#TRPBF | 功能描述:IC REG BUCK BOOST SYNC ADJ 12DFN 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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