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参数资料
| 型号： | LTC3550EDHC-1#PBF |
| 厂商： | Linear Technology |
| 文件页数： | 20/24页 |
| 文件大小： | 0K |
| 描述： | IC CHARGER BATT DUAL 16-DFN |
| 标准包装： | 73 |
| 功能： | 充电管理 |
| 电池化学： | 锂离子（Li-Ion） |
| 电源电压： | 4.3 V ~ 8 V |
| 工作温度： | -40°C ~ 85°C |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 16-WFDFN 裸露焊盘 |
| 供应商设备封装： | 16-DFN（5x3） |
| 包装： | 管件 |
LTC3550-1
APPLICATIO S I FOR ATIO
the bottom trace, a 1 Ω resistor is added in series with the
4.7μF capacitor to locally bypass the 5V input. This trace
shows the clean response resulting from the addition of
the 1 Ω resistor.
4.7 μ F ONLY
2V/DIV
4.7 μ F + 1 Ω
2V/DIV
PC Board Layout Checklist
When laying out the printed circuit board, the following
checklist should be used to ensure proper operation of
the LTC3550-1. These items are also illustrated graph-
ically 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 V CC trace should be kept short, direct
and wide.
2. Does the V OUT pin connect directly to the output?
3. Does the (+) plate of C IN connect to V CC as closely as
possible? This capacitor provides the AC current to the
20 μ s/DIV
3550-1 F04
internal power MOSFETs.
Figure 4. Waveforms Resulting from
Hot-Plugging a 5V Input Supply When
Using Ceramic Bypass Capacitors
Even with the additional 1 Ω resistor, bad design techniques
and poor board layout can often make the overvoltage
problem even worse. System designers often add extra
inductance in series with input lines in an attempt to mini-
mize the noise fed back to those inputs by the application.
In reality, adding these extra inductances only makes the
overvoltage transients worse. Since cable inductance is
one of the fundamental causes of the excessive ringing,
adding a series ferrite bead or inductor increases the ef-
fective cable inductance, making the problem even worse.
For this reason, do not add additional inductance (ferrite
beads or inductors) in series with the USB or wall adapter
inputs. For the most robust solution, 6V transorbs or zener
diodes may also be added to further protect the USB and
wall adapter inputs. Two possible protection devices are
the SM2T from STMicroelectronics and the EDZ series
devices from ROHM.
Always use an oscilloscope to check the voltage wave-
forms at the USBIN and DCIN pins during USB and wall
adapter hot-plug events to ensure that overvoltage
transients have been adequately removed.
4. Keep the (–) plates of C IN and C OUT as close as
possible.
5. Solder the exposed pad on the backside of the package
to PC board ground for optimum thermal performance.
The thermal resistance of the package can be further
enhanced by increasing the area of the copper used for
PC board ground.
Design Example
As a design example, assume the LTC3550-1 is used
in a single lithium-ion battery-powered cellular phone
application. The battery is charged by either plugging
a wall adapter into the phone or putting the phone in a
USB cradle. The optimum charge current for this parti-
cular lithium-ion battery is determined to be 800mA.
Starting with the charger, choosing R IDC to be 1.24k
programs the charger for 806mA. Choosing R IUSB to
be 2.1k programs the charger for 475mA when charging
from the USB cradle, ensuring that the charger never
exceeds the 500mA maximum current supplied by the
USB port. A good rule of thumb for I TERMINATE is one-
tenth the full charge current, so R ITERM is picked to be
1.24k (I TERMINATE = 80mA).
Moving on to the step-down converter, V CC will be pow-
ered from the battery which can range 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. Ef?ciency at both low
35501f
20
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相关代理商/技术参数 |
参数描述 |
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| LTC3552 | 制造商:LINER 制造商全称:Linear Technology 功能描述:Standalone Linear Li-Ion Battery Charger and Dual Synchronous Buck Converter |
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| LTC3552EDHC | 制造商:LINER 制造商全称:Linear Technology 功能描述:Standalone Linear Li-Ion Battery Charger and Dual Synchronous Buck Converter |
| LTC3552EDHC#PBF | 功能描述:IC CHARGER BATT LI-ION 16-DFN RoHS:是 类别:集成电路 (IC) >> PMIC - 电池管理 系列:- 标准包装:61 系列:- 功能:电源管理 电池化学:锂离子（Li-Ion）、锂聚合物（Li-Pol） 电源电压:4.35 V ~ 5.5 V 工作温度:-40°C ~ 85°C 安装类型:表面贴装 封装/外壳:22-WFDFN 裸露焊盘 供应商设备封装:22-DFN（6x3）裸露焊盘 包装:管件 |
| LTC3552EDHC#TRPBF | 功能描述:IC CHARGER BATT LI-ION 16-DFN RoHS:是 类别:集成电路 (IC) >> PMIC - 电池管理 系列:- 标准包装:61 系列:- 功能:电源管理 电池化学:锂离子（Li-Ion）、锂聚合物（Li-Pol） 电源电压:4.35 V ~ 5.5 V 工作温度:-40°C ~ 85°C 安装类型:表面贴装 封装/外壳:22-WFDFN 裸露焊盘 供应商设备封装:22-DFN（6x3）裸露焊盘 包装:管件 |
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