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参数资料
| 型号： | LT3640EUFD#PBF |
| 厂商： | LINEAR TECHNOLOGY CORP |
| 元件分类： | 稳压器 |
| 英文描述： | 3.4 A DUAL SWITCHING CONTROLLER, 2350 kHz SWITCHING FREQ-MAX, PQCC28 |
| 封装： | 5 X 4 MM, LEAD FREE, PLASTIC, MO-220, QFN-28 |
| 文件页数： | 2/24页 |
| 文件大小： | 506K |
| 代理商： | LT3640EUFD#PBF |
LT3640
0
3640f
TiMing DiagraMs
The LT3640 is a dual channel, constant-frequency, current
mode monolithic buck switching regulator with power-on
reset and watchdog timer. Both channels are synchronized
toasingleoscillatorwithfrequencysetbyRT.Operationcan
be best understood by referring to the Block Diagram.
Buck Regulators
The high voltage channel is a nonsynchronous buck
regulator that operates from the VIN pin. The start of each
oscillator cycle sets an SR latch and turns on the internal
NPN power switch. An amplifier and comparator monitor
the current flowing between the VINandSW1pins,turning
theswitchoffwhenthiscurrentreachesaleveldetermined
by the voltage at VC1 node. An error amplifier measures
the output voltage through an external resistor divider tied
to the FB1 pin and servos the VC1 node. The reference
of the error amplifier is determined by the lower of the
internalreferenceandthevoltageattheSS1pin.Iftheerror
amplifier’s output increases, more current is delivered to
the output; if it decreases, less current is delivered.
operaTion
An active clamp (not shown) on the VC1 node provides
peak current limit. A DA pin current comparator extends
the oscillator cycle until the catch diode current is below
the valley current limit. Both the peak and valley current
limits help to control the inductor current in fault condi-
tions such as shorted output with high VIN. Both current
limits are reduced when the voltage at the FB1 pin is below
0.2V. This current foldback helps to control the inductor
current during start-up and overload.
The NPN power switch driver operates from either the VIN
pin or the BST pin. An external capacitor and diode are
used to generate a voltage between the BST and SW pins.
Duringthepower-upoftheLT3640,aninternal5mAcurrent
source charges the external BST capacitor. The regulator
starts switching when the (BST-SW) voltage reaches the
2V threshold. The internal NPN power switch can be fully
saturated for efficient operation when the (BST-SW) volt-
age is between 2.3V and 5.5V.
The low voltage channel is a synchronous buck regulator
that operates from the VIN2 pin. It starts switching only
FB
RST
WDI
WDO
3640 TD
tRST
tUV
t < tWDL tRST
tDLY
t < tWDU
tWDL < t < tWDU
tWDU
tRST
Power-On Reset Timing
Watchdog Timing
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相关代理商/技术参数 |
参数描述 |
|---|---|
| LT3640EUFDTRPBF | 制造商:LINER 制造商全称:Linear Technology 功能描述:Dual Monolithic Buck Regulator with Power-On Reset and Watchdog Timer |
| LT3640IFE | 制造商:LINER 制造商全称:Linear Technology 功能描述:Dual Monolithic Buck Regulator with Power-On Reset and Watchdog Timer |
| LT3640IFE#PBF | 功能描述:IC REG BUCK FIX/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 |
| LT3640IFE#TRPBF | 功能描述:IC REG BUCK FIX/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 |
| LT3640IFEPBF | 制造商:LINER 制造商全称:Linear Technology 功能描述:Dual Monolithic Buck Regulator with Power-On Reset and Watchdog Timer |
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