参数资料
| 型号： | LTC3411IMS#TRPBF |
| 厂商： | Linear Technology |
| 文件页数： | 13/24页 |
| 文件大小： | 0K |
| 描述： | IC REG BUCK SYNC ADJ 10MSOP |
| 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 ~ 5 V |
| 输入电压： | 2.63 V ~ 5.5 V |
| PWM 型： | 电流模式，混合 |
| 频率 - 开关： | 1MHz |
| 电流 - 输出： | 1.25A |
| 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） |
| 包装： | 带卷 (TR) |
| 供应商设备封装： | 10-MSOP |
LTC3411
APPLICATIONS INFORMATION
Shutdown and Soft-Start
The SHDN/R T pin is a dual purpose pin that sets the oscil-
lator frequency and provides a means to shut down the
LTC3411. This pin can be interfaced with control logic in
several ways, as shown in Figure 3(a) and Figure 3(b).
The I TH pin is primarily for loop compensation, but it can
also be used to increase the soft-start time. Soft start
reduces surge currents from V IN by gradually increasing
the peak inductor current. Power supply sequencing can
also be accomplished using this pin. The LTC3411 has an
internal digital soft-start which steps up a clamp on I TH
over 1024 clock cycles, as can be seen in Figure 4.
The soft-start time can be increased by ramping the volt-
age on I TH during start-up as shown in Figure 3(c). As
the voltage on I TH ramps through its operating range the
internal peak current limit is also ramped at a proportional
linear rate.
Mode Selection and Frequency Synchronization
The SYNC/MODE pin is a multipurpose pin which provides
mode selection and frequency synchronization. Connect-
ing this pin to V IN enables Burst Mode operation, which
provides the best low current ef?ciency at the cost of a
higher output voltage ripple. When this pin is connected to
ground, pulse skipping operation is selected which provides
the lowest output voltage and current ripple at the cost
of low current ef?ciency. Applying a voltage between 1V
and SV IN – 1, results in forced continuous mode, which
creates a ?xed output ripple and is capable of sinking
some current (about 1/2 Δ I L ). Since the switching noise is
constant in this mode, it is also the easiest to ?lter out. In
many cases, the output voltage can be simply connected to
the SYNC/MODE pin, giving the forced continuous mode,
except at startup.
The LTC3411 can also be synchronized to an external clock
signal by the SYNC/MODE pin. The internal oscillator fre-
quency should be set to 20% lower than the external clock
frequency to ensure adequate slope compensation, since
slope compensation is derived from the internal oscillator.
During synchronization, the mode is set to pulse skipping
and the top switch turn on is synchronized to the rising
edge of the external clock.
Checking Transient Response
The OPTI-LOOP compensation allows the transient re-
sponse to be optimized for a wide range of loads and
output capacitors. The availability of the I TH pin not only
allows optimization of the control loop behavior but also
provides a DC coupled and AC ?ltered closed loop response
test point. The DC step, rise time and settling at this test
point truly re?ects the closed loop response. Assuming a
predominantly second order system, phase margin and/or
damping factor can be estimated using the percentage of
SHDN/R T
R T
SHDN/R T
R T
SV IN
1M
RUN
3411 F03a
RUN
3411 F03b
V IN
2V/DIV
V OUT
2V/DIV
(3a)
(3b)
RUN OR V IN
I TH
I L1
500mA/DIV
R1 D1
R C
V IN = 3.3V
V OUT = 2.5V
200μs/DIV
3411 F04
R L = 1.4Ω
C1
C C
3411 F03c
Figure 4. Digital Soft-Start
(3c)
Figure 3. SHDN/R T Pin Interfacing and External Soft-Start
3411fb
13
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相关代理商/技术参数 |
参数描述 |
|---|---|
| LTC3412 | 制造商:LINER 制造商全称:Linear Technology 功能描述:8A, 4MHz, Monolithic Synchronous Step-Down Regulator |
| LTC3412A | 制造商:LINER 制造商全称:Linear Technology 功能描述:3A, 4MHz, Monolithic Synchronous Step-Down Regulator |
| LTC3412AEFE | 制造商:Linear Technology 功能描述:Conv DC-DC Single Step Down 2.25V to 5.5V 16-Pin TSSOP EP |
| LTC3412AEFE#PBF | 功能描述:IC REG BUCK SYNC ADJ 3A 16TSSOP 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 |
| LTC3412AEFE#TR | 制造商:Linear Technology 功能描述:DP-SWREG/Monolithic, 3A, 4MHz, Monolithic Synch Step-Down |
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