SNOSB14E August   2009  – July 2024 LPV521

PRODUCTION DATA  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Pin Configuration and Functions
  6. 5 Specifications
    1. 5.1 Absolute Maximum Ratings
    2. 5.2 ESD Ratings
    3. 5.3 Recommended Operating Conditions
    4. 5.4 Thermal Information
    5. 5.5 Electrical Characteristics
    6. 5.6 Typical Characteristics
  7. 6 Detailed Description
    1. 6.1 Overview
    2. 6.2 Functional Block Diagram
    3. 6.3 Feature Description
    4. 6.4 Device Functional Modes
      1. 6.4.1 Input Stage
      2. 6.4.2 Output Stage
  8. 7 Applications and Implementation
    1. 7.1 Application Information
      1. 7.1.1 Driving Capacitive Load
      2. 7.1.2 EMI Suppression
    2. 7.2 Typical Applications
      1. 7.2.1 60Hz Twin T-Notch Filter
        1. 7.2.1.1 Design Requirements
        2. 7.2.1.2 Detailed Design Procedure
        3. 7.2.1.3 Application Curve
      2. 7.2.2 Portable Gas Detection Sensor
        1. 7.2.2.1 Design Requirements
        2. 7.2.2.2 Detailed Design Procedure
        3. 7.2.2.3 Application Curve
      3. 7.2.3 High-Side Battery Current Sensing
        1. 7.2.3.1 Design Requirements
        2. 7.2.3.2 Detailed Design Procedure
        3. 7.2.3.3 Application Curve
    3. 7.3 Power Supply Recommendations
    4. 7.4 Layout
      1. 7.4.1 Layout Guidelines
      2. 7.4.2 Layout Example
  9. 8 Device and Documentation Support
    1. 8.1 Device Support
      1. 8.1.1 Development Support
    2. 8.2 Documentation Support
      1. 8.2.1 Related Documentation
    3. 8.3 Receiving Notification of Documentation Updates
    4. 8.4 Support Resources
    5. 8.5 Trademarks
    6. 8.6 Electrostatic Discharge Caution
    7. 8.7 Glossary
  10. 9 Revision History
  11. 10Mechanical, Packaging, and Orderable Information

6.4.1 Input Stage

The LPV521 has a rail-to-rail input that provides more flexibility for the system designer. Rail-to-rail input is achieved by using in parallel, one PMOS differential pair and one NMOS differential pair. When the common mode input voltage (VCM) is near V+, the NMOS pair is on and the PMOS pair is off. When VCM is near V−, the NMOS pair is off and the PMOS pair is on. When VCM is between V+ and V−, internal logic decides how much current each differential pair get. This special logic maintains stable and low-distortion amplifier operation within the entire common-mode voltage range.

Both input stages have an offset voltage (VOS) characteristic; therefore, the offset voltage of the LPV521 becomes a function of VCM. VOS has a crossover point at 1.0V less than V+. See the Input Offset Voltage vs Input Common Mode curves in the Typical Characteristics. Take care in situations where the input signal amplitude is comparable to the VOS value or the design requires high accuracy. In these situations, the input signal must avoid the crossover point. In addition, parameters such as PSRR and CMRR that involve the input offset voltage are also affected by changes in VCM across the differential-pair transition region.