参数资料
| 型号： | SPX2945M3-L-5-0/TR |
| 厂商： | Exar Corporation |
| 文件页数： | 4/12页 |
| 文件大小： | 0K |
| 描述： | IC REG LDO 5V .4A SOT223-3 |
| 标准包装： | 2,500 |
| 稳压器拓扑结构： | 正，固定式 |
| 输出电压： | 5V |
| 输入电压： | 最高 26V |
| 电压 - 压降（标准）： | 0.36V @ 400mA |
| 稳压器数量： | 1 |
| 电流 - 输出： | 400mA |
| 工作温度： | -40°C ~ 85°C |
| 安装类型： | 表面贴装 |
| 封装/外壳： | TO-261-4，TO-261AA |
| 供应商设备封装： | SOT-223 |
| 包装： | 带卷 (TR) |
SPX2945 - 5.0V BLOCK DIAGRAM
UNREGULATED DC
+
7
FEEDBACK
8
INPUT
1
OUTPUT
5V at 400mA
MAX
2
SENSE
FROM
CMOS OR
3
+
_
ERROR
AMPLIFIER
180k ?
.
6
5V TAP
330k ? .
TTL
SHUTDOWN
60k ? .
5
+
60 mV
+
+ 1.23V
+
_
ERROR DETECTION
COMPARATOR
______
ERROR
1 μ F
TO CMOS OR
TTL
4
REFERENCE
GROUND
APPLICATION INFORMATION
External Capacitors
The stability of the SPX2945 requires a 2.2 μ F or
greater capacitor between output and ground.
Oscillation could occur without this capacitor.
Most types of tantalum or aluminum electrolytic
works fine here. For operations of below -25 ° C
solid tantalum is recommended since the many
aluminum types have electrolytes that freeze at
about -30 ° C. The ESR of about 5 ? or less and
resonant frequency above 500kHz are the most
important parameters in the value of the capaci-
tor. The capacitor value can be increased with-
The SPX2945, unlike other low dropout regu-
lators will remain stable and in regulation with
no load in addition to the internal voltage di-
vider. This feature is especially important in
applications like CMOS RAM keep-alive.
If there is more than 10 inches of wire between
the input and the AC filter capacitor, or if a
battery is used as the input, then a 0.1 μ F tanta-
lum or aluminum electrolytic capacitor should
be placed from the input to the ground.
out limit.
Instability can occur if there is stray capaci-
At lower values of output current, less output
capacitance is required for stability. For the
currents below 10mA the value of the capacitor
can be reduced to 0.5 μ F and 0.15 μ F for 1mA.
More output capacitance needed for the 8-pin
version at voltages below 5V since it runs the
error amplifier at lower gain. At worst case
4.7 μ F or greater must be used for the condition
of 250mA load at 1.23V output.
tance to the SPX2945 feedback terminal (pin 7).
This could cause more problems when using a
higher value of external resistors to set the
output voltage.
This problem can be fixed by adding a 100pF
capacitor between output and feedback and
increasing the output capacitor to at least 3.3 μ F.
Date: 3/14/06
SPX2945 400mA Low Dropout Voltage Regulator with Shutdown
4
?Copyright 2006 Sipex Corporation
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相关代理商/技术参数 |
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| SPX2945R | 制造商:SIPEX 制造商全称:Sipex Corporation 功能描述:500mA Low Drop Out Voltage Regulator with Shutdown |
| SPX2945R-3.3 | 制造商:SIPEX 制造商全称:Sipex Corporation 功能描述:500mA Low Drop Out Voltage Regulator with Shutdown |
| SPX2945R-3-3 | 制造商:SIPEX 制造商全称:Sipex Corporation 功能描述:400mA Low Dropout Voltage Regulator with Shutdown |
| SPX2945R-3-3TR | 制造商:SIPEX 制造商全称:Sipex Corporation 功能描述:400mA Low Dropout Voltage Regulator with Shutdown |
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