参数资料
| 型号： | MIC4684BM TR |
| 厂商： | Micrel Inc |
| 文件页数： | 11/16页 |
| 文件大小： | 0K |
| 描述： | IC REG BUCK ADJ 2A 8SOIC |
| 标准包装： | 2,500 |
| 系列： | SuperSwitcher™ |
| 类型： | 降压（降压） |
| 输出类型： | 可调式 |
| 输出数： | 1 |
| 输出电压： | 可调至 1.235V |
| 输入电压： | 4 V ~ 30 V |
| PWM 型： | 电压模式 |
| 频率 - 开关： | 200kHz |
| 电流 - 输出： | 2A |
| 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： | MIC4684BMTR MIC4684BMTR-ND |
MIC4684
A worst-case rule of thumb is to assume that 80% of the total
output power dissipation is in the MIC4684 (P D(IC) ) and 20%
is in the diode-inductor-capacitor circuit.
P D(IC) = 0.8 P D
P D(IC) = 0.8 × 0.95W
P D(IC) = 0.76W
Calculate the worst-case junction temperature:
T J = P D(IC) θ JC + (T C – T A ) + T A(max)
where:
T J = MIC4684 junction temperature
P D(IC) = MIC4684 power dissipation
θ JC = junction-to-case thermal resistance.
The θ JC for the MIC4684’s power-SOP-8 is approximately
25°C/W.
T C = “pin” temperature measurement taken at the
entry point of pins 2, 6 or 7
T A = ambient temperature
T A(max) = maximum ambient operating temperature
for the specific design.
Calculating the maximum junction temperature given a
maximum ambient temperature of 60°C:
T J = 0.76 × 25°C/W + (41°C – 25°C) + 60°C
T J = 95°C
Micrel, Inc.
This value is within the allowable maximum operating junction
temperature of 125°C as listed in “Operating Ratings.” Typical
thermal shutdown is 160°C and is listed in Electrical Charac-
teristics . Also see SOA curves on pages 7 through 8.
Layout Considerations
Layout is very important when designing any switching regu -
lator. Rapidly changing currents through the printed circuit
board traces and stray inductance can generate voltage
transients which can cause problems.
To minimize stray inductance and ground loops, keep trace
lengths as short as possible. For example, keep D1 close
to pin 1 and pins 2, 6, and 7, keep L1 away from sensitive
node FB, and keep C IN close to pin 3 and pins 2, 6, and 7.
See Applications Information: Thermal Considerations for
ground plane layout.
The feedback pin should be kept as far way from the switch -
ing elements (usually L1 and D1) as possible.
A circuit with sample layouts are provided. See Figure 7.
Gerber files are available upon request.
Feed Forward Diode
The FF diode (feed forward) provides an external bias source
directly to the main pass element, this reduces V SAT thus
allowing the MIC4684 to be used in very low head-room ap -
plications I.E. 5V IN to 3.3V OUT.
V IN
+4V to +30V
(34V transient)
C IN
Power
SOP-8
3
8
MIC4684BM
IN BS
EN SW
FB
GND
2 6 7
4
1
5
D1
L1
68μH
C OUT
V OUT
R1
R2
GND
Figure 5. Critical Traces for Layout
January 2010
11
M9999-012610
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相关代理商/技术参数 |
参数描述 |
|---|---|
| MIC4684YM | 功能描述:直流/直流开关调节器 SO-8 Efficient Simple Buck Regulator (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 |
| MIC4684YM TR | 功能描述:直流/直流开关调节器 SO-8 Efficient Simple Buck Regulator (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 |
| MIC4684YM | 制造商:Micrel Inc 功能描述:IC VOLTAGE REGULATOR SOIC |
| MIC4684YM | 制造商:Micrel Inc 功能描述:Voltage Regulator IC |
| MIC4684YMTR | 制造商:Micrel 功能描述:Conv DC-DC Single Step Down 4V to 30V |
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