ZHCSIU0D February   2000  – September 2018 LM4051-N

PRODUCTION DATA.  

  1. 特性
  2. 应用
  3. 说明
    1.     Device Images
      1. 1.2 VREF 简化原理图
      2.      可调基准简化原理图
  4. 修订历史记录
  5. Pin Configuration and Functions
    1.     Pin Functions
  6. Specifications
    1. 6.1 Absolute Maximum Ratings
    2. 6.2 ESD Ratings
    3. 6.3 Recommended Operating Conditions
    4. 6.4 Thermal Information
    5. 6.5 LM4051-1.2 Electrical Characteristics
    6. 6.6 LM4051-ADJ Electrical Characteristics
    7. 6.7 Typical Characteristics
  7. Parameter Measurement Information
  8. Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
    4. 8.4 Device Functional Modes
      1. 8.4.1 LM4051-N - 1.2 V
      2. 8.4.2 LM4051-N - ADJ
  9. Application and Implementation
    1. 9.1 Application Information
    2. 9.2 Typical Applications
      1. 9.2.1 Shunt Regulator
        1. 9.2.1.1 Design Requirements
        2. 9.2.1.2 Detailed Design Procedure
        3. 9.2.1.3 Application Curves
      2. 9.2.2 Adjustable Shunt Regulator
        1. 9.2.2.1 Design Requirements
        2. 9.2.2.2 Detailed Design Procedure
    3. 9.3 System Examples
  10. 10Power Supply Recommendations
  11. 11Layout
    1. 11.1 Layout Guidelines
    2. 11.2 Layout Example
  12. 12器件和文档支持
    1. 12.1 接收文档更新通知
    2. 12.2 社区资源
    3. 12.3 商标
    4. 12.4 静电放电警告
    5. 12.5 术语表
  13. 13机械、封装和可订购信息

请参考 PDF 数据表获取器件具体的封装图。

机械数据 (封装 | 引脚)
  • DBZ|3
散热焊盘机械数据 (封装 | 引脚)

Application Information

The LM4051-N is a precision micro-power curvature-corrected bandgap shunt voltage reference. For space critical applications, the LM4051-N is available in the sub-miniature SOT-23 surface-mount package. The LM4051-N has been designed for stable operation without the need of an external capacitor connected between the “+” pin and the “−” pin. If, however, a bypass capacitor is used, the LM4051-N remains stable. Design effort is further reduced with the choice of either a fixed 1.2-V or an adjustable reverse breakdown voltage. The minimum operating current is 60 μA for the LM4051-1.2 and the LM4051-ADJ. Both versions have a maximum operating current of 12 mA.

LM4051-N's using the SOT-23 package have pin 3 connected as the (–) output through the package’s die attach interface. Therefore, the LM4051-1.2’s pin 3 must be left floating or connected to pin 2 and the LM4051-ADJ’s pin 3 is the (–) output.

The typical thermal hysteresis specification is defined as the change in +25 ̊C voltage measured after thermal cycling. The device is thermal cycled to temperature –40 ̊C and then measured at 25 ̊C. Next the device is thermal cycled to temperature +125 ̊C and again measured at 25 ̊C. The resulting VOUT delta shift between the 25 ̊C measurements is thermal hysteresis. Thermal hysteresis is common in precision references and is induced by thermal-mechanical package stress. Changes in environmental storage temperature, operating temperature and board mounting temperature are all factors that can contribute to thermal hysteresis.

In a conventional shunt regulator application (Figure 18), an external series resistor (RS) is connected between the supply voltage and the LM4051-N. RS determines the current that flows through the load (IL) and the LM4051-N (IQ). Since load current and supply voltage may vary, RS should be small enough to supply at least the minimum acceptable IQ to the LM4051-N even when the supply voltage is at its minimum and the load current is at its maximum value. When the supply voltage is at its maximum and IL is at its minimum, RS should be large enough so that the current flowing through the LM4051-N is less than 12 mA.

RS should be selected based on the supply voltage, (VS), the desired load and operating current, (IL and IQ), and the LM4051-N's reverse breakdown voltage, VR.

Equation 1. LM4051-N eq-01-SNOS491.gif

The LM4051-ADJ’s output voltage can be adjusted to any value in the range of 1.24 V through 10 V. It is a function of the internal reference voltage (VREF) and the ratio of the external feedback resistors as shown in Figure 20. The output voltage is found using Equation 2:

Equation 2. LM4051-N eq-02-SNOS491.gif

where

  • VO is the output voltage
Equation 3. LM4051-N eq-03-SNOS491.gif

The actual value of the internal VREF is a function of VO. The corrected VREF is determined by Equation 4:

Equation 4. LM4051-N eq-04-SNOS491.gif

where

  • VY = 1.22 V

∆VREF/∆VO is found in the LM4051-ADJ Electrical Characteristics and is typically −1.55 mV/V. You can get a more accurate indication of the output voltage by replacing the value of VREF in Equation 2 with the value found using Equation 4.