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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： | 5/16页 |
| 文件大小： | 295K |
| 代理商： | LTC3543EDCB |
LTC3543
13
3543f
APPLICATIO S I FOR ATIO
WU
U
problem. For a detailed explanation of the switching control
loop theory, see Application Note 76.
A second, more severe transient is caused by switching
in loads with large (>1F) supply bypass capacitors. The
discharged bypass capacitors are effectively put in paral-
lel with COUT, causing a rapid drop in VOUT. No regulator
can deliver enough current to prevent this problem if the
load switch resistance is low and it is driven quickly. The
only solution is to limit the rise time of the switch drive
so that the load rise time is limited to approximately
25 CLOAD. Thus, a 10F capacitor charging to 3.3V would
require a 250s rise time, limiting the charging current
to about 130mA.
PC Board Layout Checklist
When laying out the printed circuit board, the following
checklist should be used to ensure proper operation of
the LTC3543. These items are also illustrated graphically
in Figures 5 and 6. Check the following in your layout:
1. The power traces, consisting of the GND trace, the SW
trace, and the VIN trace should be kept short, direct
and wide.
2. Does the VFB pin connect directly to the feedback voltage
reference? Ensure that there is no load current running
from the feedback reference voltage and the VFB pin.
3. Does the (+) plate of CIN connect to VIN as closely as
possible? This capacitor provides the AC current to the
internal power MOSFETs.
4. Keep the switching node, SW, away from the sensitive
VFB node.
5. Keep the (–) plates of CIN and COUT as close as pos-
sible.
Design Example
As a design example, assume the LTC3543 is used in
a single lithium-ion battery-powered cellular phone ap-
plication. The VIN will be operating from a maximum of
4.2V down to about 2.7V. The load current requirement
is a maximum of 600mA, but most of the time it will be
in standby mode, requiring only 2mA. Efciency at both
low and high load currents is important. Output voltage
is 1.5V. With this information we can calculate L using
Equation 1,
L
V
fI
V
OUT
L
OUT
IN
=
1
A 3.3H inductor works well for this application, yielding
a ripple current of only 130mA. For best efciency choose
a 665mA or greater inductor with less than 0.05Ω series
resistance.
In Equation 2, CIN will require an RMS current rating of at
least 0.3A at ILOAD(MAX)/2 at temperature.
Using Equation 3, Selecting a 4.7F capacitor with an
ESR of 0.05Ω for COUT yields an 8mV voltage ripple on
the regulated output voltage.
For feedback resistors, choose R1 = 402k. R2 can then
be calculated using Equation 4.
R
V
Rk
OUT
2
06
1
1 604
=
=
.
Figure 6 shows the complete circuit along with its ef-
ciency curve.
4
5
6
3
2
1
R1
R2
SW
VIN
VFB
MODE
RUN
CFWD
CIN
C1
GND
L
VIN
CAP
VOUT
COUT
3543 F07
+–
+
–
+
–
+–
Figure 5. LTC3543 Layout Diagram
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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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