参数资料
| 型号： | LT3686HDD#TRPBF |
| 厂商： | Linear Technology |
| 文件页数： | 11/28页 |
| 文件大小： | 0K |
| 描述： | IC REG BUCK ADJ 1.2A 10DFN |
| 标准包装： | 2,500 |
| 类型： | 降压（降压） |
| 输出类型： | 可调式 |
| 输出数： | 1 |
| 输出电压： | 0.8 V ~ 30 V |
| 输入电压： | 3.6 V ~ 37 V |
| PWM 型： | 电流模式 |
| 频率 - 开关： | 300kHz ~ 2.5MHz |
| 电流 - 输出： | 1.2A |
| 同步整流器： | 无 |
| 工作温度： | -40°C ~ 150°C |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 10-WFDFN 裸露焊盘 |
| 包装： | 带卷 (TR) |
| 供应商设备封装： | 10-DFN（3x3） |
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LT3686
APPLICATIONS INFORMATION
V OUT + V D
V IN(MAX) = – V D + V SW
Themaximuminputvoltageisdeterminedbytheabsolute
maximum ratings of the V IN and BOOST pins. For fixed
frequency operation, the maximum input voltage is de-
termined by the minimum duty cycle DC MIN :
DC MIN
DC MIN can be adjusted with frequency. Note that this is a
restriction on the operating input voltage for fixed frequency
operation; the circuit will tolerate transient inputs up to
the absolute maximum ratings of the V IN and BOOST pins.
Minimum On Time
As the input voltage is increased, the LT3686 is required
to switch for shorter periods of time. Delays associated
with turning off the power switch dictate the minimum on
time of the part. The minimum on time for the LT3686 is
100ns (Figure 3).
V SW
10V/DIV
I L
500mA/DIV
When the required on time decreases below the typical
minimum on time of 100ns, instead of the switch pulse
width becoming narrower to accommodate the lower duty
cycle requirement, the switch pulse width remains fixed at
100ns. The inductor current ramps up to a value exceed-
ing the load current and the output ripple increases. The
part then remains off until the output voltage dips below
the programmed value before it begins switching again
(Figure 4).
Provided that the load can tolerate the increased output
voltage ripple and that the components have been properly
selected, operation while pulse skipping is safe and will
not damage the part. As the input voltage increases, the
inductor current ramps up quicker, the number of skipped
pulses increases, and the output voltage ripple increases.
Inductor current may reach current limit when operating
in pulse skip mode with small valued inductors. In this
case, the LT3686 will periodically reduce its frequency to
keep the inductor valley current to 1.7A (Figure 5). Peak
V SW
20V/DIV
I L
500mA/DIV
V OUT
100mV/DIV
AC
500ns/DIV
3686 F03
V OUT
100mA/DIV
AC
2μs/DIV
3686 F04
V IN = 18V
V OUT = 3.3V
L = 6.8μH
C OUT = 22μF
I LOAD = 1.2mA
Figure 3. Continuous Mode Operation Near Minimum On Time
V IN = 35V
V OUT = 3.3V
L = 6.8μH
C OUT = 22μF
I OUT = 300mA
Figure 4. Pulse Skip Occurs When Required On Time Is
Below 100ns
3686fc
11
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相关代理商/技术参数 |
参数描述 |
|---|---|
| LT3686IDD | 制造商:LINER 制造商全称:Linear Technology 功能描述:37V/1.2A Step-Down Regulator in 3mm × 3mm DFN |
| LT3686IDD#PBF | 功能描述:IC REG BUCK ADJ 1.2A 10DFN 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 |
| LT3686IDD#PBF | 制造商:Linear Technology 功能描述:DC-DC CONVERTER BUCK 2.5MHZ 制造商:Linear Technology 功能描述:DC-DC CONVERTER, BUCK, 2.5MHZ, DFN-10 |
| LT3686IDD#TRPBF | 功能描述:IC REG BUCK ADJ 1.2A 10DFN 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 |
| LT3686IDDPBF | 制造商:LINER 制造商全称:Linear Technology 功能描述:37V/1.2A Step-Down Regulator in 3mm × 3mm DFN |
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