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参数资料
| 型号： | LM3411A-3.3MWC |
| 厂商： | NATIONAL SEMICONDUCTOR CORP |
| 元件分类： | 基准电压源/电流源 |
| 英文描述： | 1-OUTPUT THREE TERM VOLTAGE REFERENCE, 3.3 V, UUC |
| 封装： | WAFER |
| 文件页数： | 14/16页 |
| 文件大小： | 403K |
| 代理商： | LM3411A-3.3MWC |
Product Description
The LM3411 is a shunt regulator specifically designed to be
the reference and control section in an overall feedback loop
of a regulated power supply. The regulated output voltage is
sensed between the IN pin and GROUND pin of the LM3411.
If the voltage at the IN pin is less than the LM3411 regulating
voltage (V
REG), the OUT pin sources no current. As the volt-
age at the IN pin approaches the V
REG voltage, the OUT pin
begins sourcing current. This current is then used to drive a
feedback device, (opto-coupler) or a power device, (linear
regulator, switching regulator, etc.) which servos the output
voltage to be the same value as V
REG.
In some applications, (even under normal operating condi-
tions) the voltage on the IN pin can be forced above the
V
REG voltage. In these instances, the maximum voltage ap-
plied to the IN pin should not exceed 20V. In addition, an ex-
ternal resistor may be required on the OUT pin to limit the
maximum current to 20 mA.
Compensation
The inverting input of the error amplifier is brought out to al-
low overall closed-loop compensation. In many of the appli-
cations circuits shown here, compensation is provided by a
single capacitor connected from the compensation pin to the
out pin of the LM3411. The capacitor values shown in the
schematics are adequate under most conditions, but they
can be increased or decreased depending on the desired
loop response. Applying a load pulse to the output of a regu-
lator circuit and observing the resultant output voltage re-
sponse is a easy method of determining the stability of the
control loop. Analyzing more complex feedback loops re-
quires additional information.
The formula for AC gain at a frequency (f) is as follows;
where R
f ≈ 52 k for the 3.3V part, and Rf ≈ 94 k for the 5V
part.
The resistor (R
f) in the formula is an internal resistor located
on the die. Since this resistor value will affect the phase mar-
gin, the worst case maximum and minimum values are im-
portant when analyzing closed loop stability. The minimum
and maximum room temperature values of this resistor are
specified in the Electrical Characteristics section of this data
sheet, and a curve showing the temperature coefficient is
shown in the curves section. In the applications shown here,
the worst case phase margin occurs with minimum values of
R
f.
Test Circuit
The test circuit shown in
Figure 2 can be used to measure
and verify various LM3411 parameters. Test conditions are
set by forcing the appropriate voltage at the V
OUT Set test
point and selecting the appropriate R
L or IOUT as specified in
the Electrical Characteristics section. Use a DVM at the
“measure” test points to read the data.
DS011987-14
FIGURE 2. LM3411 Test Circuit
LM341
1
www.national.com
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相关PDF资料 |
PDF描述 |
|---|---|
| LM3411A-3.3MDC | 1-OUTPUT THREE TERM VOLTAGE REFERENCE, 3.3 V, UUC |
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| LM385D-2.5 | 1-OUTPUT TWO TERM VOLTAGE REFERENCE, 2.5 V, PDSO8 |
| LM385BLP-2.5 | 1-OUTPUT TWO TERM VOLTAGE REFERENCE, 2.5 V, PBCY3 |
| LM385LP-2.5 | 1-OUTPUT TWO TERM VOLTAGE REFERENCE, 2.5 V, PBCY3 |
相关代理商/技术参数 |
参数描述 |
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| LM3411AM5-3.3 | 功能描述:基准电压& 基准电流 RoHS:否 制造商:STMicroelectronics 产品:Voltage References 拓扑结构:Shunt References 参考类型:Programmable 输出电压:1.24 V to 18 V 初始准确度:0.25 % 平均温度系数（典型值）:100 PPM / C 串联 VREF - 输入电压（最大值）: 串联 VREF - 输入电压（最小值）: 分流电流（最大值）:60 mA 最大工作温度:+ 125 C 封装 / 箱体:SOT-23-3L 封装:Reel |
| LM3411AM5-3.3/NOPB | 功能描述:基准电压& 基准电流 RoHS:否 制造商:STMicroelectronics 产品:Voltage References 拓扑结构:Shunt References 参考类型:Programmable 输出电压:1.24 V to 18 V 初始准确度:0.25 % 平均温度系数（典型值）:100 PPM / C 串联 VREF - 输入电压（最大值）: 串联 VREF - 输入电压（最小值）: 分流电流（最大值）:60 mA 最大工作温度:+ 125 C 封装 / 箱体:SOT-23-3L 封装:Reel |
| LM3411AM5-5.0 | 功能描述:基准电压& 基准电流 RoHS:否 制造商:STMicroelectronics 产品:Voltage References 拓扑结构:Shunt References 参考类型:Programmable 输出电压:1.24 V to 18 V 初始准确度:0.25 % 平均温度系数（典型值）:100 PPM / C 串联 VREF - 输入电压（最大值）: 串联 VREF - 输入电压（最小值）: 分流电流（最大值）:60 mA 最大工作温度:+ 125 C 封装 / 箱体:SOT-23-3L 封装:Reel |
| LM3411AM5-5.0/NOPB | 功能描述:基准电压& 基准电流 RoHS:否 制造商:STMicroelectronics 产品:Voltage References 拓扑结构:Shunt References 参考类型:Programmable 输出电压:1.24 V to 18 V 初始准确度:0.25 % 平均温度系数（典型值）:100 PPM / C 串联 VREF - 输入电压（最大值）: 串联 VREF - 输入电压（最小值）: 分流电流（最大值）:60 mA 最大工作温度:+ 125 C 封装 / 箱体:SOT-23-3L 封装:Reel |
| LM3411AM5-5.0/NOPB | 制造商:Texas Instruments 功能描述:, Voltage Regulator Type:Fixed Positive |
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