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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： | 16/16页 |
| 文件大小： | 295K |
| 代理商： | LTC3543EDCB |
LTC3543
9
3543f
APPLICATIO S I FOR ATIO
WU
U
OPERATIO
U
Slope Compensation and Inductor Peak Current
Slope compensation provides stability in constant-
frequency architectures by preventing subharmonic
oscillations at high duty cycles. It is accomplished in-
ternally by adding a compensating ramp to the inductor
current signal at duty cycles in excess of 40%. Normally,
this results in a reduction of maximum inductor peak
current for duty cycles >40%; however, the LTC3543
uses a patent-pending scheme that counteracts this com-
pensating ramp, allowing the maximum inductor peak
current to remain unaffected throughout all duty cycles.
Figure 2. Maximum Output Current vs Input Voltage (VIN)
The basic LTC3543 application circuit is shown on the
front page of this datasheet. External component selec-
tion is driven by the load requirement and begins with the
selection of L followed by CIN and COUT.
Inductor Selection
For most applications, the value of the inductor will fall
in the range of 1H to 4.7H. Its value is chosen based
on the desired ripple current. Large value inductors
lower ripple current, and small value inductors result in
higher ripple currents. Higher VIN or VOUT also increases
the ripple current, as shown in Equation 1. A reasonable
starting point for setting ripple current is ΔIL = 130mA
20% ILOADMAX.
I
V
fL
V
L
OUT
IN
=
1
(1)
The DC current rating of the inductor should be at least
equal to the maximum load current plus half the ripple
current to prevent core saturation. Thus, a 665mA rated
inductor should be enough for most applications (600mA
+ 65mA). For better efciency, choose a low DC-resistance
inductor.
The inductor value also has an effect on Burst Mode opera-
tion. The transition to low current operation begins when
the inductor current peaks fall to approximately 100mA.
Lower inductor values (higher ΔIL) will cause this to occur
at lower load currents, which can cause a dip in efciency
in the upper range of low current operation. In Burst Mode
operation, lower inductance values will cause the burst
frequency to increase.
Inductor Core Selection
Different core materials and shapes will change the
size/current and price/current relationship of an
inductor. Toroid or shielded pot cores in ferrite or
permalloy materials are small and don’t radiate much
energy, but generally cost more than powdered iron core
inductors with similar electrical characteristics. The choice
of which style inductor to use often depends more on the
price vs size requirements, and any radiated eld/EMI re-
quirements, than on what the LTC3543 requires to operate.
Table 1 shows some typical surface mount inductors that
work well in LTC3543 applications.
CIN and COUT Selection
In continuous mode, the source current of the top MOSFET
is a square wave of duty cycle VOUT/VIN. To prevent large
voltage transients, a low ESR input capacitor sized for the
maximum RMS current must be used. The maximum RMS
capacitor current is given by:
C
required I
I
[V
(V –V
)]
IN
RMS
OMAX
OUT
IN
OUT
1/2
V
VIN
(2)
INPUT VOLTAGE (V)
2.5
500
MAXIMUM
OUTPUT
CURRENT
(mA)
700
900
1100
3.0
3.5
4.0
4.5
3543 F02
5.0
1300
1500
600
800
1000
1200
1400
5.5
VOUT = 1.5V
VOUT = 1.2V
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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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