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参数资料
| 型号： | LT3430EFE-1#TR |
| 厂商： | LINEAR TECHNOLOGY CORP |
| 元件分类： | 稳压器 |
| 英文描述： | 6.5 A SWITCHING REGULATOR, 120 kHz SWITCHING FREQ-MAX, PDSO16 |
| 封装： | 4.40 MM, PLASTIC, TSSOP-16 |
| 文件页数： | 10/28页 |
| 文件大小： | 321K |
| 代理商： | LT3430EFE-1#TR |
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LT3430/LT3430-1
18
34301fa
The VC and FB components should be kept as far away as
possible from the switch and boost nodes. The LT3430/
LT3430-1 pinout has been designed to aid in this. The
ground for these components should be separated from
the switch current path. Failure to do so will result in poor
stability or subharmonic like oscillation.
Board layout also has a signicant effect on thermal
resistance. Pins 1, 8, 9 and 16, GND, should be soldered
to a continuous copper ground plane under the LT3430/
LT3430-1 die. The FE package has an exposed pad (Pin
17) which is the best thermal path for heat out of the
package. Soldering the exposed pad to the copper ground
plane under the device will reduce die temperature and
increase the power capability of the LT3430/LT3430-1. Add-
ing multiple solder lled feedthroughs under and around
the four corner pins to the ground plane will also help.
Similar treatment to the catch diode and coil terminations
will reduce any additional heating effects.
PARASITIC RESONANCE
Resonance or “ringing” may sometimes be seen on the
switch node (see Figure 7). Very high frequency ringing
following switch rise time is caused by switch/diode/input
capacitor lead inductance and diode capacitance. Schottky
diodes have very high “Q” junction capacitance that can
ring for many cycles when excited at high frequency. If
total lead length for the input capacitor, diode and switch
path is 1 inch, the inductance will be approximately 25nH.
At switch off, this will produce a spike across the NPN
output device in addition to the input voltage. At higher
currents this spike can be in the order of 10V to 20V
or higher with a poor layout, potentially exceeding the
absolute max switch voltage. The path around switch,
catch diode and input capacitor must be kept as short as
possible to ensure reliable operation. When looking at this,
a >100MHz oscilloscope must be used, and waveforms
should be observed on the leads of the package. This
switch off spike will also cause the SW node to go below
ground. The LT3430/LT3430-1 have special circuitry inside
which mitigates this problem, but negative voltages over
0.8V lasting longer than 10ns should be avoided. Note that
100MHz oscilloscopes are barely fast enough to see the
details of the falling edge overshoot in Figure 7.
A second, much lower frequency ringing is seen during
switch off time if load current is low enough to allow the
inductor current to fall to zero during part of the switch off
time (see Figure 8). Switch and diode capacitance reso-
nate with the inductor to form damped ringing at 1MHz
to 10MHz. This ringing is not harmful to the regulator
and it has not been shown to contribute signicantly to
EMI. Any attempt to damp it with a resistive snubber will
degrade efciency.
APPLICATIONS INFORMATION
50ns/DIV
3430 F07
2V/DIV
SW RISE
SW FALL
VIN = 40V
VOUT = 5V
L = 22
H
3430 F08
1
s/DIV
10mV/DIV
SWITCH NODE
VOLTAGE
INDUCTOR
CURRENT AT
IOUT = 0.1A
0.2A/DIV
LT3430
Figure 7. Switch Node Resonance
Figure 8. Discontinuous Mode Ringing
相关PDF资料 |
PDF描述 |
|---|---|
| LT3430IFE-1 | 6.5 A SWITCHING REGULATOR, 120 kHz SWITCHING FREQ-MAX, PDSO16 |
| LT3430EFE-1 | 6.5 A SWITCHING REGULATOR, 120 kHz SWITCHING FREQ-MAX, PDSO16 |
| LT3467AIDDB#PBF | 2.5 A SWITCHING REGULATOR, 2700 kHz SWITCHING FREQ-MAX, PDSO8 |
| LT3467AIDDB | 2.5 A SWITCHING REGULATOR, 2700 kHz SWITCHING FREQ-MAX, PDSO8 |
| LT3467IS6#TRM | 2.5 A SWITCHING REGULATOR, 1600 kHz SWITCHING FREQ-MAX, PDSO6 |
相关代理商/技术参数 |
参数描述 |
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| LT3430EFEPBF | 制造商:Linear Technology 功能描述:LT3430 adj 3A Buck SD dc-dc converter |
| LT3430IFE | 功能描述:IC REG BUCK ADJ 3A 16TSSOP RoHS:否 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 |
| LT3430IFE#PBF | 功能描述:IC REG BUCK ADJ 3A 16TSSOP RoHS:否 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 |
| LT3430IFE#PBF | 制造商:Linear Technology 功能描述:DC/DC Converter IC |
| LT3430IFE#TR | 功能描述:IC REG BUCK ADJ 3A 16TSSOP RoHS:否 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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