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参数资料
| 型号： | MIC4680-5.0BM TR |
| 厂商： | Micrel Inc |
| 文件页数： | 11/15页 |
| 文件大小： | 0K |
| 描述： | IC REG BUCK 5V 1A 8SOIC |
| 标准包装： | 2,500 |
| 系列： | SuperSwitcher™ |
| 类型： | 降压（降压） |
| 输出类型： | 固定 |
| 输出数： | 1 |
| 输出电压： | 5V |
| 输入电压： | 4 V ~ 34 V |
| PWM 型： | 电压模式 |
| 频率 - 开关： | 200kHz |
| 电流 - 输出： | 1A |
| 同步整流器： | 无 |
| 工作温度： | -40°C ~ 125°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 |
| 其它名称： | MIC4680-5.0BMTR |
Micrel, Inc.
Thermal Considerations
The MIC4680 SuperSwitcher features the power-SOIC-
8. This package has a standard 8-pin small-outline
package profile but with much higher power dissipation
than a standard SOIC-8. The MIC4680 SuperSwitcher is
the first dc-to-dc converter to take full advantage of this
package.
The reason that the power SOIC-8 has higher power
SOIC-8
MIC4680
BIE
dissipation (lower thermal resistance) is that pins 5
though 8 and the die-attach paddle are a single piece of
metal. The die is attached to the paddle with thermally
conductive adhesive. This provides a low thermal
JC
JA
CA
AM
N
T
ground plane
heat sink area
resistance path from the junction of the die to the ground
pins. This design significantly improves package power
dissipation by allowing excellent heat transfer through
the ground leads to the printed circuit board.
One of the limitation of the maximum output current on
any MIC4680 design is the junction-to-ambient thermal
resistance ( θ JA ) of the design (package and ground
plane).Examining θ JA in more detail:
printed circuit board
Figure 2. Power SOIC-8 Cross Section
Minimum Copper/Maximum Current Method
Using Figure 3, for a given input voltage range,
determine the minimum ground-plane heat-sink area
where:
θ JA = ( θ JC + θ CA )
θ JC = junction-to-case thermal resistance
required for the application’s maximum output current.
Figure 3 assumes a constant die temperature of 75°C
above ambient.
θ CA = case-to-ambient thermal resistance
θ JC is a relatively constant 20°C/W for a power SOIC-8.
1.5
8V
12V
θ CA is dependent on layout and is primarily governed by
the connection of pins 5 though 8 to the ground plane.
The purpose of the ground plane is to function as a heat
sink.
θ JA is ideally 63°C/W but will vary depending on the size
of the ground plane to which the power SOIC-8 is
1.0
0.5
24V
34V
T A = 50°C
Minimum Current Limit = 1.3A
attached.
Determining Ground-Plane Heat-Sink Area
There are two methods of determining the minimum
ground plane area required by the MIC4680.
Quick Method
Make sure that MIC4680 pins 5 though 8 are connected
to a ground plane with a minimum area of 6cm 2 . This
ground plane should be as close to the MIC4680 as
possible. The area maybe distributed in any shape
around the package or on any pcb layer as long as there
is good thermal contact to pins 5 though 8. This ground
plane area is more than sufficient for most designs.
0
0 5 10 15 20 25
AREA (cm 2 )
Figure 3. Output Current vs. Ground Plane Area
When designing with the MIC4680, it is a good practice
to connect pins 5 through 8 to the largest ground plane
that is practical for the specific design.
Checking the Maximum Junction Temperature:
For this example, with an output power (P OUT ) of 5W, (5V
output at 1A maximum with V IN = 12V) and 65°C
maximum ambient temperature, what is the maximum
junction temperature?
Referring to the “Typical Characteristics: 5V Output
Efficiency” graph, read the efficiency ( η ) for 1A output
current at V IN = 12V or perform you own measurement.
η = 79%
The efficiency is used to determine how much of the
output power (P OUT ) is dissipated in the regulator circuit
(P D ).
March 2008
11
M9999-032808
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相关代理商/技术参数 |
参数描述 |
|---|---|
| MIC4680BM | 功能描述:IC REG BUCK ADJ 1.3A 8SOIC RoHS:否 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 开关稳压器 系列:SuperSwitcher™ 标准包装:20 系列:SIMPLE SWITCHER® 类型:降压（降压） 输出类型:固定 输出数:1 输出电压:12V 输入电压:4 V ~ 60 V PWM 型:电压模式 频率 - 开关:52kHz 电流 - 输出:1A 同步整流器:无 工作温度:-40°C ~ 125°C 安装类型:通孔 封装/外壳:16-DIP（0.300"，7.62mm） 包装:管件 供应商设备封装:16-DIP 其它名称:*LM2575HVN-12LM2575HVN-12 |
| MIC4680BM TR | 功能描述:IC REG BUCK ADJ 1.3A 8SOIC RoHS:否 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 开关稳压器 系列:SuperSwitcher™ 标准包装:20 系列:SIMPLE SWITCHER® 类型:降压（降压） 输出类型:固定 输出数:1 输出电压:12V 输入电压:4 V ~ 60 V PWM 型:电压模式 频率 - 开关:52kHz 电流 - 输出:1A 同步整流器:无 工作温度:-40°C ~ 125°C 安装类型:通孔 封装/外壳:16-DIP（0.300"，7.62mm） 包装:管件 供应商设备封装:16-DIP 其它名称:*LM2575HVN-12LM2575HVN-12 |
| MIC4680BMTR | 制造商:Rochester Electronics LLC 功能描述:- Tape and Reel |
| MIC4680YM | 功能描述:直流/直流开关调节器 1.3A SuperSwitcher in SO-8 (Lead Free) RoHS:否 制造商:International Rectifier 最大输入电压:21 V 开关频率:1.5 MHz 输出电压:0.5 V to 0.86 V 输出电流:4 A 输出端数量: 最大工作温度: 安装风格:SMD/SMT 封装 / 箱体:PQFN 4 x 5 |
| MIC4680YM TR | 功能描述:直流/直流开关调节器 1.3A SuperSwitcher in SO-8 (Lead Free) RoHS:否 制造商:International Rectifier 最大输入电压:21 V 开关频率:1.5 MHz 输出电压:0.5 V to 0.86 V 输出电流:4 A 输出端数量: 最大工作温度: 安装风格:SMD/SMT 封装 / 箱体:PQFN 4 x 5 |
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