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| 型号： | LTC4054ES5-4.2#TRMPBF |
| 厂商： | LINEAR TECHNOLOGY CORP |
| 元件分类： | 电源管理 |
| 英文描述： | Standalone Linear Li-Ion Battery Charger with Thermal Regulation in ThinSOT; Package: SOT; No of Pins: 5; Temperature Range: -40°C to +125°C |
| 中文描述： | 2-CHANNEL POWER SUPPLY SUPPORT CKT, PDSO5 |
| 封装： | LEAD FREE, PLASTIC, TSOT-23, 5 PIN |
| 文件页数： | 3/16页 |
| 文件大小： | 185K |
| 代理商： | LTC4054ES5-4.2#TRMPBF |
11
LTC4054-4.2/LTC4054X-4.2
405442xf
The following table lists thermal resistance for several
different board sizes and copper areas. All measurements
were taken in still air on 3/32" FR-4 board with the device
mounted on topside.
Table 1. Measured Thermal Resistance (2-Layer Board*)
COPPER AREA
BOARD
THERMAL RESISTANCE
TOPSIDE
BACKSIDE
AREA
JUNCTION-TO-AMBIENT
2500mm2
125
°C/W
1000mm2
2500mm2
125
°C/W
225mm2
2500mm2
130
°C/W
100mm2
2500mm2
135
°C/W
50mm2
2500mm2
150
°C/W
Table 2. Measured Thermal Resistance (4-Layer Board**)
COPPER AREA
BOARD
THERMAL RESISTANCE
(EACH SIDE)
AREA
JUNCTION-TO-AMBIENT
2500mm2***
2500mm2
80
°C/W
Increasing Thermal Regulation Current
Reducing the voltage drop across the internal MOSFET
can significantly decrease the power dissipation in the IC.
This has the effect of increasing the current delivered to
the battery during thermal regulation. One method is by
dissipating some of the power through an external compo-
nent, such as a resistor or diode.
Example: An LTC4054 operating from a 5V wall adapter is
programmed to supply 800mA full-scale current to a
discharged Li-Ion battery with a voltage of 3.75V. Assum-
ing
θJA is 125°C/W, the approximate charge current at an
ambient temperature of 25
°C is:
I
CC
VV
C W
mA
BAT =
°°
°
=
120
25
5
3 75
125
608
–
(– .
)
/
By dropping voltage across a resistor in series with a 5V
wall adapter (shown in Figure 3), the on-chip power
dissipation can be decreased, thus increasing the ther-
mally regulated charge current
I
CC
VI
R
V
BAT
S
BAT CC
BAT
JA
=
°°
120
25
–
(–
–
)
θ
APPLICATIO S I FOR ATIO
WU
UU
The LTC4054 can be used above 45
°C ambient, but the
charge current will be reduced from 400mA. The approxi-
mate current at a given ambient temperature can be
approximated by:
I
CT
VV
BAT
A
CC
BAT
JA
=
°
()
120
–
θ
Using the previous example with an ambient temperature
of 60
°C, the charge current will be reduced to approxi-
mately:
I
CC
VV
C W
C
CA
ImA
BAT
=
°°
() °
=
°
=
120
60
5
3 75
150
60
187 5
320
–
–.
/
./
Moreover, when thermal feedback reduces the charge
current, the voltage at the PROG pin is also reduced
proportionally as discussed in the Operation section.
It is important to remember that LTC4054 applications do
not need to be designed for worst-case thermal conditions
since the IC will automatically reduce power dissipation
when the junction temperature reaches approximately
120
°C.
Thermal Considerations
Because of the small size of the ThinSOT package, it is very
important to use a good thermal PC board layout to
maximize the available charge current. The thermal path
for the heat generated by the IC is from the die to the
copper lead frame, through the package leads, (especially
the ground lead) to the PC board copper. The PC board
copper is the heat sink. The footprint copper pads should
be as wide as possible and expand out to larger copper
areas to spread and dissipate the heat to the surrounding
ambient. Feedthrough vias to inner or backside copper
layers are also useful in improving the overall thermal
performance of the charger. Other heat sources on the
board, not related to the charger, must also be considered
when designing a PC board layout because they will affect
overall temperature rise and the maximum charge current.
*Each layer uses one ounce copper
*Top and bottom layers use two ounce copper, inner layers use one ounce copper.
**10,000mm2 total copper area
相关PDF资料 |
PDF描述 |
|---|---|
| LTC4054ES5-4.2#TRPBF | Standalone Linear Li-Ion Battery Charger with Thermal Regulation in ThinSOT; Package: SOT; No of Pins: 5; Temperature Range: -40°C to +125°C |
| LTC4054XES5-4.2#TRMPBF | Standalone Linear Li-Ion Battery Charger with Thermal Regulation in ThinSOT; Package: SOT; No of Pins: 5; Temperature Range: -40°C to +125°C |
| LTC4054LES5-4.2#TRMPBF | Standalone Linear Li-Ion Battery Charger with Thermal Regulation in ThinSOT; Package: SOT; No of Pins: 5; Temperature Range: -40°C to +125°C |
| LTC4055EUF#PBF | USB Power Controller and Li-Ion Linear Charger; Package: QFN; No of Pins: 16; Temperature Range: -40°C to +125°C |
| LTF5022T-4R7N2R0-LC | 1 ELEMENT, 4.7 uH, FERRITE-CORE, GENERAL PURPOSE INDUCTOR, SMD |
相关代理商/技术参数 |
参数描述 |
|---|---|
| LTC4054L | 制造商:LINER 制造商全称:Linear Technology 功能描述:150mA Standalone Linear Li-Ion Battery Charger in ThinSOT |
| LTC4054L-4.2 | 制造商:LINER 制造商全称:Linear Technology 功能描述:150mA Standalone Linear Li-Ion Battery Charger in ThinSOT |
| LTC4054LES5-4.2 | 制造商:Linear Technology 功能描述:Battery Charger Li-Ion 10mA to 150mA 4.2V 5-Pin TSOT-23 |
| LTC4054LES5-4.2#PBF | 制造商:Linear Technology 功能描述:Bulk 制造商:Linear Technology 功能描述:CHARGER BATTERY LI-ION 0.8A 5SOT23 制造商:Linear Technology 功能描述:CHARGER, BATTERY, LI-ION, 0.8A, 5SOT23 |
| LTC4054LES5-4.2#TR | 功能描述:IC CHARGR BATTERY L-ION TSOT23-5 RoHS:否 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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