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參數(shù)資料
| 型號： | LTC4080EMSE |
| 廠商： | LINEAR TECHNOLOGY CORP |
| 元件分類： | 穩(wěn)壓器 |
| 英文描述： | 0.8 A BATTERY CHARGE CONTROLLER, 2750 kHz SWITCHING FREQ-MAX, PDSO10 |
| 封裝： | PLASTIC, MSOP-10 |
| 文件頁數(shù)： | 9/20頁 |
| 文件大?。?/td> | 288K |
| 代理商： | LTC4080EMSE |
LTC4080
17
4080fa
APPLICATIO S I FOR ATIO
WU
U
Where VOUT is the regulated output of the switching
regulator, IOUT is the regulator load and η is the regulator
efciency at that particular load.
It is not necessary to perform worst-case power dissipa-
tion scenarios because the LTC4080 will automatically
reduce the charge current to maintain the die temperature
at approximately 115°C. However, the approximate ambi-
ent temperature at which the thermal feedback begins to
protect the IC is:
TA = 115°C – PDθJA
TA = 115°C – (VCC – VBAT) IBAT θJA if the regulator
is off.
Example: Consider the extreme case when an LTC4080 is
operating from a 6V supply providing 250mA to a 3V Li-Ion
battery and the regulator is off. The ambient temperature
above which the LTC4080 will begin to reduce the 250mA
charge current is approximately:
TA = 115°C – (6V – 3V) (250mA) 43°C/W
TA = 115°C – 0.75W 43°C/W = 115°C – 32.25°C
TA = 82.75°C
If there is more power dissipation due to the regulator,
the thermal regulation will kick in at a somewhat lower
temperature than this. In the above circumstances, the
LTC4080 can be used above 82.75°C, but the charge current
will be reduced from 250mA. The approximate current at
a given ambient temperature can be calculated:
I
CT
VV
BAT
A
CC
BAT
JA
=
°
()
115
θ
Using the previous example with an ambient temperature
of 85°C, the charge current will be reduced to approxi-
mately:
I
CC
VV
C W
C
CA
BAT =
° °
() °
=
°
=
115
85
63
43
30
129
2
/
3
32 6
.mA
Note: 1V = 1J/C = 1W/A
Furthermore, the voltage at the PROG pin will change
proportionally with the charge current as discussed in
the Programming Charge Current section.
VCC Bypass Capacitor
Many types of capacitors can be used for input bypassing;
however, caution must be exercised when using multi-layer
ceramic capacitors. Because of the self-resonant and high
Q characteristics of some types of ceramic capacitors, high
voltage transients can be generated under some start-up con-
ditions, such as connecting the battery charger input to a live
power source. Adding a 1
Ω series resistor in series with an
X5Rceramiccapacitorwillminimizestart-upvoltagetransients.
For more information, refer to Application Note 88.
SWITCHING REGULATOR
Setting the Buck Converter Output Voltage
The LTC4080 regulator compares the FB pin voltage with
an internal 0.8V reference to generate an error signal at the
output of the error amplier. A voltage divider from VOUT
to ground (as shown in the Block Diagram) programs the
output voltage via FB using the formula:
VV
R
OUT =+
08
1
7
8
.
Keeping the current low (<5A) in these resistors maxi-
mizes efciency, but making them too low may allow stray
capacitance to cause noise problems and reduce the phase
margin of the error amp loop. To improve the frequency
response, a phase-lead capacitor (CPL) of approximately
10pF can be used. Great care should be taken to route the
FB line away from noise sources, such as the inductor or
the SW line.
Inductor Selection
The value of the inductor primarily determines the cur-
rent ripple in the inductor. The inductor ripple
current
ΔIL decreases with higher inductance and
increases with higher VIN or VOUT:
I
V
fL
V
L
OUT
IN
=
0
1
Accepting larger values of
ΔIL allows the use of low
inductances, but results in higher output voltage ripple,
greater core losses, and lower output current capability. A
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| LTC4080EMSE#PBF | 功能描述:IC CHARGER LI-ION 10-MSOP RoHS:是 類別:集成電路 (IC) >> PMIC - 電池管理 系列:- 標準包裝:61 系列:- 功能:電源管理 電池化學:鋰離子（Li-Ion）、鋰聚合物（Li-Pol） 電源電壓:4.35 V ~ 5.5 V 工作溫度:-40°C ~ 85°C 安裝類型:表面貼裝 封裝/外殼:22-WFDFN 裸露焊盤 供應(yīng)商設(shè)備封裝:22-DFN（6x3）裸露焊盤 包裝:管件 |
| LTC4080EMSE#TRPBF | 功能描述:IC CHARGER LI-ION 10-MSOP RoHS:是 類別:集成電路 (IC) >> PMIC - 電池管理 系列:- 標準包裝:61 系列:- 功能:電源管理 電池化學:鋰離子（Li-Ion）、鋰聚合物（Li-Pol） 電源電壓:4.35 V ~ 5.5 V 工作溫度:-40°C ~ 85°C 安裝類型:表面貼裝 封裝/外殼:22-WFDFN 裸露焊盤 供應(yīng)商設(shè)備封裝:22-DFN（6x3）裸露焊盤 包裝:管件 |
| LTC4080EMSE-PBF | 制造商:LINER 制造商全稱:Linear Technology 功能描述:500mA Standalone Li-Ion Charger with Integrated 300mA Synchronous Buck |
| LTC4080EMSE-TRPBF | 制造商:LINER 制造商全稱:Linear Technology 功能描述:500mA Standalone Li-Ion Charger with Integrated 300mA Synchronous Buck |
| LTC4080X | 制造商:LINER 制造商全稱:Linear Technology 功能描述:500mA Standalone Li-Ion Charger with Integrated 300mA Synchronous Buck in 3mm × 3mm DFN |
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