SBOS110C May   1998  – March 2023 OPA2227 , OPA2228 , OPA227 , OPA228 , OPA4227 , OPA4228

PRODUCTION DATA  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Revision History
  5. 5 Pin Configuration and Functions
  6. 6 Specifications
    1. 6.1 Absolute Maximum Ratings
    2. 6.2 ESD Ratings
    3. 6.3 Recommended Operating Conditions
    4. 6.4 Thermal Information: OPA227, OPA228
    5. 6.5 Thermal Information: OPA2227, OPA2228
    6. 6.6 Thermal Information: OPA4227, OPA4228
    7. 6.7 Electrical Characteristics: OPAx227 
    8. 6.8 Electrical Characteristics: OPAx228 
    9. 6.9 Typical Characteristics
  7. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1 Offset Voltage and Drift
      2. 7.3.2 Operating Voltage
      3. 7.3.3 Offset Voltage Adjustment
      4. 7.3.4 Input Protection
      5. 7.3.5 Input Bias Current Cancellation
      6. 7.3.6 Noise Performance
      7. 7.3.7 Basic Noise Calculations
      8. 7.3.8 EMI Rejection Ratio (EMIRR)
        1. 7.3.8.1 EMIRR IN+ Test Configuration
    4. 7.4 Device Functional Modes
  8. 8 Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Application
      1. 8.2.1 Using the OPAx228 in Low Gains
        1. 8.2.1.1 Design Requirements
        2. 8.2.1.2 Detailed Design Procedure
        3. 8.2.1.3 Application Curves
      2. 8.2.2 Three-Pole, 20 kHz Low Pass, 0.5-dB Chebyshev Filter
      3. 8.2.3 Long-Wavelength Infrared Detector Amplifier
      4. 8.2.4 High Performance Synchronous Demodulator
      5. 8.2.5 Headphone Amplifier
      6. 8.2.6 Three-Band Active Tone Control (Bass, Midrange, and Treble)
    3. 8.3 Power Supply Recommendations
    4. 8.4 Layout
      1. 8.4.1 Layout Guidelines
      2. 8.4.2 Layout Example
  9. 9 Device and Documentation Support
    1. 9.1 Device Support
      1. 9.1.1 Development Support
        1. 9.1.1.1 TINA-TI™ Simulation Software (Free Download)
        2. 9.1.1.2 TI Reference Designs
    2. 9.2 Documentation Support
      1. 9.2.1 Related Documentation
    3. 9.3 Receiving Notification of Documentation Updates
    4. 9.4 Support Resources
    5. 9.5 Trademarks
    6. 9.6 Electrostatic Discharge Caution
    7. 9.7 Glossary
  10. 10Mechanical, Packaging, and Orderable Information

Package Options

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

7.3.6 Noise Performance

Figure 7-4 shows the total circuit noise for varying source impedances with the operational amplifier in a unity-gain configuration (no feedback resistor network; therefore, no additional noise contributions). Two different operational amplifiers are shown with total circuit noise calculated. The OPA227 has very low voltage noise, making this device an excellent choice for low source impedances (less than 20 kΩ). A similar precision operational amplifier, the OPA277, has somewhat higher voltage noise but lower current noise. The OPA277 provides excellent noise performance at moderate source impedance (10 kΩ to 100 kΩ). Above 100 kΩ, a FET-input operational amplifier such as the OPA132 (very low current noise) can provide improved performance. Use the equation in Figure 7-4 to calculate the total circuit noise, where en = voltage noise, in = current noise, RS = source impedance, k = Boltzmann’s constant = 1.38 × 10–23 J/K, and T is temperature in K. For more details on calculating noise, see Section 7.3.7.

GUID-766CD136-D0CA-4242-A155-40380BC62B5D-low.gif Figure 7-4 Noise Performance of the OPA227 in Unity-Gain Buffer Configuration