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参数资料
| 型号： | LTC3543EDCB |
| 厂商： | LINEAR TECHNOLOGY CORP |
| 元件分类： | 稳压器 |
| 英文描述： | 1.3 A SWITCHING REGULATOR, 2250 kHz SWITCHING FREQ-MAX, PDSO6 |
| 封装： | 2 X 3 MM, 0.75 MM HEIGHT, PLASTIC, MO-229, DFN-6 |
| 文件页数： | 3/16页 |
| 文件大小： | 295K |
| 代理商： | LTC3543EDCB |
LTC3543
11
3543f
APPLICATIO S I FOR ATIO
WU
U
frequencies are the same but exhibit a phase difference,
current pulses (sourcing or sinking) are used for an amount
of time corresponding to the phase difference. The current
pulses adjust the voltage on the CAP pin until the phase
and frequency of the internal and external oscillators are
identical. At the stable operating point, the CAP pin is high
impedance and the external capacitor holds the voltage.
The external cap is used by the PLL’s loop lter to help
smooth out the voltage change and provide a stable input
to the voltage-controlled oscillator. The value of C1 will
determine how fast the loop acquires lock. Typically C1
is 1nF to 10nF in PLL mode. A value of 2.2nF is suitable
in most applications.
Using Ceramic Capacitors for CIN, COUT and C1
High value, low cost ceramic capacitors are now becoming
available in smaller case sizes. Their high ripple current,
high voltage rating and low ESR make them ideal for switch-
ing regulator applications. Because the LTC3543’s control
loop does not depend on the output capacitor’s ESR for
stable operation, ceramic capacitors can be used freely to
achieve very low output ripple and small circuit size.
However, care must be taken when ceramic capacitors are
used at the input and the output. When a ceramic capacitor
is used at the input and the power is supplied by a wall
adapter through long wires, a load step at the output can
induce ringing at the input, VIN. This ringing can couple to
the output and be mistaken as loop instability. Even worse,
the sudden inrush of current through the long wires can
potentially cause a voltage spike at VIN, large enough to
damage the part.
When choosing the input and output ceramic capacitors,
choose the X5R or X7R dielectric formulations. These
dielectrics have the best temperature and voltage charac-
teristics of all the ceramics for a given value and size.
Output Voltage Programming
The output voltage is set by a resistor divider according
to the following formula:
VV
R
OUT =+
06
1
2
1
.
(4)
The external resistor divider is connected to the output
allowing remote voltage sensing as shown in Figure 3.
Efciency Considerations
The efciency 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 efciency and which change would produce
the most improvement. Efciency can be expressed as:
Efciency = 100% – (L1 + L2 + L3 + ...)
where L1, L2, etc. are the individual losses as a percent-
age of input power.
Although all dissipative elements in the circuit produce
losses, two main sources usually account for most of
the losses in LTC3543 circuits: VIN quiescent current and
I2R losses. The VIN quiescent current loss dominates
the efciency loss at very low load currents whereas the
I2R loss dominates the efciency loss at medium to high
load currents. In a typical efciency plot, the efciency
curve at very low load currents can be misleading since
the actual power lost is of no consequence as illustrated
in Figure 4.
Figure 3. Setting Output Voltage
Figure 4. Power Loss vs Load Current
3543 F03
LTC3543
VFB
GND
R1
R2
0.6V
≤ VOUT < 5.5V
LOAD CURRENT (mA)
100
POWER
LOSS
(mW)
200
300
400
500
0.1
10
100
1000
3543 F04
0
1
VOUT = 1.2V
VOUT = 1.5V
VOUT = 1.8V
VOUT = 2.5V
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相关代理商/技术参数 |
参数描述 |
|---|---|
| LTC3543EDCB#PBF | 制造商:Linear Technology 功能描述:REG STEP DOWN 0.6A SMD DFN-6 制造商:Linear Technology 功能描述:REG, STEP DOWN, 0.6A, SMD, DFN-6 |
| LTC3543EDCB#TRMPBF | 功能描述:IC REG BUCK SYNC ADJ 0.6A 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 |
| LTC3543EDCB#TRPBF | 功能描述:IC REG BUCK SYNC ADJ 0.6A 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 |
| LTC3544 | 制造商:LINER 制造商全称:Linear Technology 功能描述:Quad Synchronous Step-Down Regulator: 2.25MHz, 300mA, 200mA, 200mA, 100mA |
| LTC3544B | 制造商:LINER 制造商全称:Linear Technology 功能描述:Quad Synchronous Step-Down Regulator: 2.25MHz, 300mA, 200mA, 200mA, 100mA |
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