SNOSDB6D December   2020  – October 2024 LMP7704-SP

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 VS = 5 V
    6. 5.6 Electrical Characteristics VS = 10 V
    7. 5.7 Typical Characteristics
  7. 6 Detailed Description
    1. 6.1 Overview
    2. 6.2 Functional Block Diagram
    3. 6.3 Feature Description
      1. 6.3.1 Radiation Hardened Performance
      2. 6.3.2 Engineering Model (Devices With /EM Suffix)
      3. 6.3.3 Diodes Between the Inputs
      4. 6.3.4 Capacitive Load
      5. 6.3.5 Input Capacitance
    4. 6.4 Device Functional Modes
      1. 6.4.1 Precision Current Source
  8. 7 Application and Implementation
    1. 7.1 Application Information
      1. 7.1.1 Low Input Voltage Noise
      2. 7.1.2 Total Noise Contribution
    2. 7.2 Typical Application
      1. 7.2.1 Design Requirements
      2. 7.2.2 Detailed Design Procedure
      3. 7.2.3 Application Curves
    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 Related Documentation
    2. 8.2 Receiving Notification of Documentation Updates
    3. 8.3 Support Resources
    4. 8.4 Trademarks
    5. 8.5 Electrostatic Discharge Caution
    6. 8.6 Glossary
  10. 9 Revision History
  11. 10Mechanical, Packaging, and Orderable Information

7.1.1 Low Input Voltage Noise

The LMP7704-SP has a very low input voltage noise of 9 nV/√Hz. This input voltage noise is further reduced by placing N amplifiers in parallel, as shown in Figure 7-1. The total voltage noise on the output of this circuit is divided by the square root of the number of amplifiers used in this parallel combination. The reason is because each individual amplifier acts as an independent noise source, and the average noise of independent sources is the quadrature sum of the independent sources divided by the number of sources. For N identical amplifiers:

Equation 6. LMP7704-SP

Figure 7-1 shows a schematic of this input voltage noise reduction circuit. Typical resistor values are:

RG = 10 Ω, RF = 1 kΩ, and RO = 1 kΩ.

LMP7704-SP Noise Reduction CircuitFigure 7-1 Noise Reduction Circuit