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参数资料
| 型号： | LTC3560IS6#TRPBF |
| 厂商： | Linear Technology |
| 文件页数： | 10/16页 |
| 文件大小： | 0K |
| 描述： | IC REG BUCK SYNC ADJ TSOT23-6 |
| 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： | 0.6 V ~ 5.5 V |
| 输入电压： | 2.5 V ~ 5.5 V |
| PWM 型： | 电流模式，混合 |
| 频率 - 开关： | 2.25MHz |
| 电流 - 输出： | 800mA |
| 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： | SOT-23-6 细型，TSOT-23-6 |
| 包装： | 带卷 (TR) |
| 供应商设备封装： | TSOT-23-6 |
LTC3560
APPLICATIONS INFORMATION
0.6V ≤ V OUT ≤ 5.5V
1. The V IN quiescent current is due to two components:
LTC3560
V FB
GND
R2
R1
3560 F02
the DC bias current as given in the electrical charac-
teristics and the internal main switch and synchronous
switch gate charge currents. The gate charge current
results from switching the gate capacitance of the
internal power MOSFET switches. Each time the gate
is switched from high to low to high again, a packet of
Figure 2. Setting the LTC3560 Output Voltage
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
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:
Ef?ciency = 100% – (L1 + L2 + L3 + ...)
where L1, L2, etc. are the individual losses as a percentage
of input power.
Although all dissipative elements in the circuit produce
losses, two main sources usually account for most of
the losses in LTC3560 circuits: 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 load currents can be misleading since
the actual power lost is of no consequence as illustrated
in Figure 3.
charge, dQ, moves from V IN to ground. The resulting
dQ/dt is the current out of V IN that is typically larger
than the DC bias current. In continuous mode, I GATECHG
= f(Q T + Q B ) where Q T and Q B are the gate charges of
the internal top and bottom switches. Both the DC bias
and gate charge losses are proportional to V IN and thus
their effects will be more pronounced at higher supply
voltages.
2. I 2 R losses are calculated from the resistances of the
internal switches, R SW , and external inductor R L . In
continuous mode, the average output current ?owing
through inductor L is “chopped” between the main
switch and the synchronous switch. Thus, the series
resistance looking into the SW pin is a function of both
top and bottom MOSFET R DS(ON) and the duty cycle
(DC) as follows:
R SW = (R DS(ON)TOP )(DC) + (R DS(ON)BOT )(1 – DC)
The R DS(ON) for both the top and bottom MOSFETs can
be obtained from the Typical Performance Charateristics
curves. Thus, to obtain I 2 R losses, simply add R SW to
R L and multiply the result by the square of the average
output current.
1
0.1
0.01
V OUT = 2.5V
Burst Mode OPERATION
Other losses including C IN and C OUT ESR dissipative losses
and inductor core losses generally account for less than
2% total additional loss.
Thermal Considerations
In most applications the LTC3560 does not dissipate
much heat due to its high ef?ciency. But, in applica-
0.001
V IN = 3.6V
V IN = 4.2V
tions where the LTC3560 is running at high ambient
temperature with low supply voltage and high duty cycles,
0.0001
V IN = 5.5V
such as in dropout, the heat dissipated may exceed the
0.1
1
10 100
LOAD CURRENT (mA)
1000
3560 F03
maximum junction temperature of the part. If the junction
temperature reaches approximately 150°C, both power
Figure 3. Power Lost vs Load Current
3560fb
10
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| LTC3561AEDD#PBF | 功能描述:IC REG BUCK SYNC ADJ 1A 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 |
| LTC3561AEDD#TRPBF | 功能描述:IC REG BUCK SYNC ADJ 1A 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 |
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