SNOSAZ6C August   2008  – November 2015 LMV831 , LMV832 , LMV834


  1. Features
  2. Applications
  3. Description
    1.     Device Images
      1.      Typical Application
  4. Revision History
  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 Electrical Characteristics, 3.3 V
    6. 6.6 Electrical Characteristics, 5 V
    7. 6.7 Typical Characteristics
  7. Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1 Input Characteristics
      2. 7.3.2 EMIRR
      3. 7.3.3 EMIRR Definition
        1. Coupling an RF Signal to the IN+ Pin
        2. Cell Phone Call
    4. 7.4 Device Functional Modes
      1. 7.4.1 Output Characteristics
      2. 7.4.2 CMRR Measurement
  8. Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Application
      1. 8.2.1 Design Requirements
      2. 8.2.2 Detailed Design Procedure
      3. 8.2.3 Application Curve
  9. Power Supply Recommendations
  10. 10Layout
    1. 10.1 Layout Guidelines
    2. 10.2 Layout Example
  11. 11Device and Documentation Support
    1. 11.1 Device Support
      1. 11.1.1 Development Support
    2. 11.2 Documentation Support
      1. 11.2.1 Related Documentation
    3. 11.3 Related Links
    4. 11.4 Community Resources
    5. 11.5 Trademarks
    6. 11.6 Electrostatic Discharge Caution
    7. 11.7 Glossary
  12. 12Mechanical, Packaging, and Orderable Information

Package Options

Mechanical Data (Package|Pins)
Thermal pad, mechanical data (Package|Pins)
Orderable Information

Coupling an RF Signal to the IN+ Pin

Each of the operational amplifier pins can be tested separately on EMIRR. In this section, the measurements on the IN+ pin (which, based on symmetry considerations, also apply to the IN– pin) are discussed. In AN-1698 (SNOA497) the other pins of the operational amplifier are treated as well. For testing the IN+ pin the operational amplifier is connected in the unity gain configuration. Applying the RF signal is straightforward as it can be connected directly to the IN+ pin. As a result the RF signal path has a minimum of components that might affect the RF signal level at the pin. The circuit diagram is shown in Figure 44. The PCB trace from RFIN to the IN+ pin should be a 50-Ω stripline in order to match the RF impedance of the cabling and the RF generator. On the PCB a 50-Ω termination is used. This 50-Ω resistor is also used to set the bias level of the IN+ pin to ground level. For determining the EMIRR, two measurements are needed: one is measuring the DC output level when the RF signal is off; and the other is measuring the DC output level when the RF signal is switched on. The difference of the two DC levels is the output voltage shift as a result of the RF signal. As the operational amplifier is in the unity-gain configuration, the input referred offset voltage shift corresponds one-to-one to the measured output voltage shift.

LMV831 LMV832 LMV834 30024167.gifFigure 44. Circuit for Coupling the RF Signal to IN+