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参数资料
| 型号： | LTC3418EUHF#TRPBF |
| 厂商： | Linear Technology |
| 文件页数： | 12/20页 |
| 文件大小： | 0K |
| 描述： | IC REG BUCK SYNC ADJ 8A 38QFN |
| 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： | 2.25 V ~ 5.5 V |
| PWM 型： | 电流模式，混合 |
| 频率 - 开关： | 1MHz |
| 电流 - 输出： | 8A |
| 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： | 38-WFQFN 裸露焊盘 |
| 包装： | 带卷 (TR) |
| 供应商设备封装： | 38-QFN（5x7） |
LTC3418
APPLICATIONS INFORMATION
The output voltage during tracking can be calculated with
the following equation:
top MOSFET turn-on is locked to the falling edge of the
external frequency source. The synchronization frequency
V OUT = V TRACK 1 +
R2
R1
,V TRACK < 0.8V
range is 300kHz to 4MHz. Synchronization only occurs if
the external frequency is greater than the frequency set
by the external resistor. Because slope compensation
To implement the coincident tracking in Figure 2a, con-
nect an extra resistor divider to the output of V OUT2 and
connect its midpoint to the TRACK pin of the LTC3418
as shown in Figure 3. The ratio of this divider should be
selected the same as that of V OUT1 ’s resistor divider. To
implement the ratiometric sequencing in Figure 2b, the extra
resistor divider’s ratio should be set so that the TRACK pin
voltage exceeds 1.05V by the end of the start-up period.
The LTC3418 utilizes a method in which the TRACK pin’s
control over the output voltage is gradually released as
the TRACK pin voltage approaches 0.8V. With this tech-
nique, some overdrive will be required on the TRACK pin
to ensure that the tracking function is completely disabled
at the end of the start-up period.
For coincident tracking, the following condition should
is generated by the oscillator’s RC circuit, the external
frequency should be set 25% higher than the frequency
set by the external resistor to ensure that adequate slope
compensation is present.
Soft-Start
The RUN/SS pin provides a means to shut down the
LTC3418 as well as a timer for soft-start. Pulling the RUN/
SS pin below 0.5V places the LTC3418 in a low quiescent
current shutdown state (I Q < 1.5μA).
The LTC3418 contains a soft-start clamp that can be set
externally with a resistor and capacitor on the RUN/SS
pin as shown in Typical Application on the front page of
this data sheet. The soft-start duration can be calculated
by using the following formula:
be satis?ed to ensure that tracking is disabled at the end
of start-up.
t SS = R SS ? C SS ?In
V IN
V IN – 1. 8 V
?? Seconds ??
V OUT2 ≥ 1.32 V OUT1
For ratiometric tracking, the following equation can be
used to calculate the resistor values:
When the voltage on the RUN/SS pin is raised above 2V,
the full current range becomes available on I TH .
R4 = R3
V OUT2
V TRACK
–1
Ef?ciency Considerations
The ef ?ciency of a switching regulator is equal to the output
power divided by the input power times 100%. It is often
V TRACK 1.05V
V OUT2
useful to analyze individual losses to determine what is
limiting the ef ?ciency and which change would produce
the most improvement. Ef ?ciency can be expressed as:
(MASTER)
R4
R2
Ef ?ciency = 100% – (L1 + L2 + L3 + ...)
TRACK
PIN
R3
R1
V FB(MASTER)
PIN
where L1, L2, etc. are the individual losses as a percent-
age of input power.
3418 F03
Figure 3
Frequency Synchronization
The LTC3418’s internal oscillator can be synchronized
to an external clock signal. During synchronization, the
Although all dissipative elements in the circuit produce
losses, two main sources usually account for most of the
losses: V IN quiescent current and I 2 R losses.
The V IN quiescent current loss dominates the ef?ciency loss
at very low load currents whereas the I 2 R loss dominates
the ef ?ciency loss at medium to high load currents. In a
typical ef ?ciency plot, the ef ?ciency curve at very low
3418fb
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相关代理商/技术参数 |
参数描述 |
|---|---|
| LTC3419 | 制造商:LINER 制造商全称:Linear Technology 功能描述:Dual Monolithic 600mA Synchronous Step-Down Regulator |
| LTC3419EDD | 制造商:LINER 制造商全称:Linear Technology 功能描述:Dual Monolithic 600mA Synchronous Step-Down Regulator |
| LTC3419EDD#PBF | 功能描述:IC REG BUCK SYNC ADJ .6A DL 8DFN 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 |
| LTC3419EDD#TRPBF | 功能描述:IC REG BUCK SYNC ADJ .6A DL 8DFN 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:升压（升压） 输出类型:可调式 输出数:1 输出电压:1.24 V ~ 30 V 输入电压:1.5 V ~ 12 V PWM 型:电流模式，混合 频率 - 开关:600kHz 电流 - 输出:500mA 同步整流器:无 工作温度:-40°C ~ 85°C 安装类型:表面贴装 封装/外壳:8-SOIC（0.154"，3.90mm 宽） 包装:带卷 (TR) 供应商设备封装:8-SOIC |
| LTC3419EDD-1 | 制造商:LINER 制造商全称:Linear Technology 功能描述:Dual Monolithic 600mA Synchronous Step-Down Regulator |
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