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参数资料
| 型号： | LT3640IFE#TRPBF |
| 厂商： | Linear Technology |
| 文件页数： | 17/24页 |
| 文件大小： | 0K |
| 描述： | IC REG BUCK FIX/ADJ DL 28TSSOP |
| 标准包装： | 2,000 |
| 类型： | 降压（降压） |
| 输出类型： | 两者兼有 |
| 输出数： | 2 |
| 输出电压： | 1.8V，3.3V，可调 |
| 输入电压： | 2.5 V ~ 35 V |
| PWM 型： | 电流模式，混合 |
| 频率 - 开关： | 500kHz ~ 2MHz |
| 电流 - 输出： | 1.1A，1.3A |
| 同步整流器： | 无 |
| 工作温度： | -40°C ~ 125°C |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 28-SOIC（0.173"，4.40mm 宽）裸露焊盘 |
| 包装： | 带卷 (TR) |
| 供应商设备封装： | 28-TSSOP 裸露焊盘 |
LT3640
APPLICATIONS INFORMATION
In the event of V IN undervoltage lockout, V IN overvoltage
lockout or the EN/UVLO pin being driven below 1.26V, the
soft-start latch is set, triggering a start-up sequence.
A latch is set to discharge the SS2 pin at power-up. After
the FB1 pin reaches 1.165V, the V IN2 voltage is above 2.3V,
the EN2 pin is enabled, and the SS2 pin is below 100mV,
the latch is reset. The internal 2μA current source starts
to charge the SS2 pin.
EN
2V/DIV
V OUT1
2V/DIV
V OUT2
1V/DIV
PGOOD
2V/DIV
500μs/DIV
3640 F04
1μs/DIV
1μs/DIV
In the event of V FB1 out of regulation, the V IN2 pin falling
below 2.2V, or the EN pin going low, the SS2 discharging
latch is set, triggering a start-up sequence.
The SS pins can also be pulled up by external current
sources or resistors for output tracking. The external pull-
up current should not exceed 100μA for either SS pin.
Figure 4 shows the soft-start for a 3.3V and 1.8V
application.
Shorted-Output Protection
If an inductor is chosen that will not saturate excessively,
the LT3640 will tolerate a shorted output. For the high
voltage channel, the DA current comparator extends the
internal oscillator period until the catch diode current is
below its limit. Both the top switch and the DA comparator
have current foldback to help limit load current when the
output is shorted to ground. The DA current limit is 1.7A
when the FB1 voltage is above 0.2V, and is 1A when the
FB1 voltage is below 0.2V. Figure 5 shows the high voltage
channel operation under shorted output.
Because of the low V IN2 voltage, the low voltage channel
does not have current foldback. The low voltage channel
does not extend the internal oscillator in shorted output
condition allowing the high voltage channel to operate
in constant frequency. If the bottom MOSFET current
exceeds the NMOS current limit at the start of a clock
cycle, the top MOSFET is kept off in this cycle (similar to
pulse-skipping operation). The inductor valley current is
kept below the NMOS current limit to ensure robustness
in shorted output condition (Figure 6).
V IN = 12V
R T SET = 2MHz
Figure 4. Soft-Start of LT3640
SW1
10V/DIV
I L1
0.5A/DIV
3640 F05
V IN = 30V
V OUT1 = SHORT
Figure 5. The High Voltage Channel Reduces Frequency
to Protect Against Shorted Output With 30V Input
SW2
2V/DIV
I L2
1A/DIV
3640 F06
V IN2 = 5V
V OUT2 = SHORT
Figure 6. The Low Voltage Channel Operates in
Pulse-Skipping Mode to Protect Against Shorted Output
3640f
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相关代理商/技术参数 |
参数描述 |
|---|---|
| LT3640IUFD | 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 |
| LT3640IUFD#PBF | 功能描述:IC REG BUCK FIX/ADJ DL 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 |
| LT3640IUFD#TRPBF | 功能描述:IC REG BUCK FIX/ADJ DL 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 |
| LT3640IUFDPBF | 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 |
| LT3640IUFDTRPBF | 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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