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参数资料
| 型号： | LTC3442EDE#TRPBF |
| 厂商： | Linear Technology |
| 文件页数： | 8/20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
OPERATION
f (kHz) =
? ( 2 ? V IN – V OUT ) ?
? ?
70 ? ? 0.86 +
R LIM(k ? ) =
C LIM( μ F) ≥
The LTC3442 provides high efficiency, low noise power
for applications such as portable instrumentation. The
LTC proprietary topology allows input voltages above,
below or equal to the output voltage by properly phasing
the output switches. The error amp output voltage on V C
determines the output duty cycle of the switches. Since V C
is a filtered signal, it provides rejection of frequencies from
well below the switching frequency. The low R DS(ON) , low
gate charge synchronous switches provide high frequency
pulse width modulation control at high efficiency. Schottky
diodes across the synchronous switch D and synchronous
switch B are not required, but provide a lower voltage
drop during the break-before-make time (typically 15ns).
Schottky diodes will improve peak efficiency by typically
1% to 2%. High efficiency is achieved at light loads when
Burst Mode operation is entered and the IC’s quiescent
current drops to a low 35μA.
LOW NOISE FIXED FREQUENCY OPERATION
Oscillator
The frequency of operation is programmed by an external
resistor from R T to ground, according to the following
equation:
43,300
R T(k ? )
Error Amp
The error amplifier is a voltage mode amplifier. The loop
compensation components are configured around the
amplifier (from FB to V C ) to obtain stability of the converter.
For improved bandwidth, an additional RC feedforward
network can be placed across the upper feedback divider
resistor. The voltage on SHDN /SS clamps the error amp
output, V C , to provide a soft-start function.
Internal Current Limit
There are three different current limit circuits in the
LTC3442. Two have internally fixed thresholds which vary
inversely with V IN , the third is externally programmable,
and does not vary with input voltage.
The first circuit is a high speed peak current limit amplifier
that will shut off switch A if the current exceeds 5A typi-
cal. The delay to output of this amplifier is typically 50ns.
A second amplifier will begin to source current into the FB
pin to drop the output voltage once the peak input current
exceeds 3A typical. This method provides a closed loop
means of clamping the input current. During conditions
where V OUT is near ground, such as during a short-circuit
or during startup, this threshold is cut in half, providing a
foldback feature. For this current limit feature to be most
effective, the Thevenin resistance from FB to ground should
be greater than 100kΩ.
Externally Programmable Current Limit
The third current limit circuit is programmed by an external
resistor on R LIM . This circuit works by mirroring the input
current in switch A, averaging it by means of the external
RC network on R LIM , and comparing the resulting voltage
with an internal reference. If the voltage on R LIM starts
to exceed 0.95V, a G m amplifier will clamp V C , lowering
V OUT to maintain control of the input current. This allows
the user to program a maximum average input current, for
applications such as USB, where the current draw from the
bus must be limited to 500mA. The resistor and capacitor
values are determined by the following equations:
? 40
I IN(AMPS)
0.1
R LIM(k ? )
The programmable current limit feature is disabled in
Burst Mode operation.
3442fb
8
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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