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参数资料
| 型号： | LTC3440EDD#TRPBF |
| 厂商： | Linear Technology |
| 文件页数： | 9/20页 |
| 文件大小： | 0K |
| 描述： | IC REG BUCK BOOST SYNC ADJ 10DFN |
| 标准包装： | 2,500 |
| 类型： | 降压（降压），升压（升压） |
| 输出类型： | 可调式 |
| 输出数： | 1 |
| 输出电压： | 2.5 V ~ 5.5 V |
| 输入电压： | 2.5 V ~ 5.5 V |
| PWM 型： | Burst Mode? |
| 频率 - 开关： | 2MHz |
| 电流 - 输出： | 600mA |
| 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： | 10-WFDFN 裸露焊盘 |
| 包装： | 带卷 (TR) |
| 供应商设备封装： | 10-DFN（3x3） |
LTC3440
OPERATIO
75%
The input voltage, V IN , where the four switch region begins
D MAX
BOOST
V4 ( ≈ 2.05V)
is given by:
BOOST REGION
V IN =
V OUT
D MIN
BOOST
D MAX
BUCK
0%
DUTY
CYCLE
A ON, B OFF
PWM CD SWITCHES
FOUR SWITCH PWM BUCK/BOOST REGION
D ON, C OFF
PWM AB SWITCHES BUCK REGION
3440 F02
V3 ( ≈ 1.65V)
V2 ( ≈ 1.55V)
V1 ( ≈ 0.9V)
INTERNAL
CONTROL
V
1 – ( 150 ns ? f )
The point at which the four switch region ends is given by:
V IN = V OUT (1 – D) = V OUT (1 – 150ns ? f) V
Boost Region (V IN < V OUT )
VOLTAGE, V CI
Figure 2. Switch Control vs Internal Control Voltage, V CI
Buck Region (V IN > V OUT )
Switch D is always on and switch C is always off during this
mode. When the internal control voltage, V CI , is above
voltage V1, output A begins to switch. During the off time
of switch A, synchronous switch B turns on for the
remainder of the time. Switches A and B will alternate
similar to a typical synchronous buck regulator. As the
control voltage increases, the duty cycle of switch A
increases until the maximum duty cycle of the converter in
Buck mode reaches D MAX _ BUCK , given by:
D MAX _ BUCK = 100 – D4 SW %
where D4 SW = duty cycle % of the four switch range.
D4 SW = (150ns ? f) ? 100 %
where f = operating frequency, Hz.
Switch A is always on and switch B is always off during
this mode. When the internal control voltage, V CI , is above
voltage V3, switch pair CD will alternately switch to
provide a boosted output voltage. This operation is typical
to a synchronous boost regulator. The maximum duty
cycle of the converter is limited to 75% typical and is
reached when V CI is above V4.
Burst Mode Operation
Burst Mode operation is when the IC delivers energy to the
output until it is regulated and then goes into a sleep mode
where the outputs are off and the IC is consuming only
25 μ A. In this mode the output ripple has a variable
frequency component that depends upon load current.
During the period where the device is delivering energy to
the output, the peak current will be equal to 400mA typical
and the inductor current will terminate at zero current for
each cycle. In this mode the maximum average output
current is given by:
Beyond this point the “four switch,” or Buck/Boost region
is reached.
I OUT ( MAX ) BURST ≈
0 . 1 ? V IN
V OUT + V IN
A
Buck/Boost or Four Switch (V IN ~ V OUT )
When the internal control voltage, V CI , is above voltage V2,
switch pair AD remain on for duty cycle D MAX_BUCK , and
the switch pair AC begins to phase in. As switch pair AC
phases in, switch pair BD phases out accordingly. When
the V CI voltage reaches the edge of the Buck/Boost range,
at voltage V3, the AC switch pair completely phase out the
BD pair, and the boost phase begins at duty cycle D4 SW .
Burst Mode operation is user controlled, by driving the
MODE/SYNC pin high to enable and low to disable.
The peak efficiency during Burst Mode operation is less
than the peak efficiency during fixed frequency because
the part enters full-time 4-switch mode (when servicing
the output) with discontinuous inductor current as illus-
trated in Figures 3 and 4. During Burst Mode operation, the
control loop is nonlinear and cannot utilize the control
3440fb
9
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相关代理商/技术参数 |
参数描述 |
|---|---|
| LTC3440EMS | 功能描述:IC REG BUCK BST SYNC 0.6A 10MSOP RoHS:否 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 |
| LTC3440EMS#PBF | 功能描述:IC REG BUCK BST SYNC 0.6A 10MSOP 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 |
| LTC3440EMS#TR | 功能描述:IC REG BUCK BST SYNC 0.6A 10MSOP RoHS:否 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 |
| LTC3440EMS#TRPBF | 功能描述:IC REG BUCK BST SYNC 0.6A 10MSOP 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 |
| LTC3440EMSPBF | 制造商:Linear Technology 功能描述:LTC3440 adj 600mA SU/SD dc-dc converter |
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