SBOSA38A February   2021  – April 2021 OPA2607-Q1 , OPA607-Q1

PRODUCTION DATA  

  1. Features
  2. Applications
  3. Description
  4. Revision History
  5. Device Comparison
  6. Pin Configuration and Functions
  7. Specifications
    1. 7.1 Absolute Maximum Ratings
    2. 7.2 ESD Ratings
    3. 7.3 Recommended Operating Conditions
    4. 7.4 Thermal Information
    5. 7.5 Electrical Characteristics
    6. 7.6 Typical Characteristics
  8. Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1 Operating Voltage
      2. 8.3.2 Rail-to-Rail Output and Driving Capacitive Loads
      3. 8.3.3 Input and ESD Protection
      4. 8.3.4 Decompensated Architecture with Wide Gain-Bandwidth Product
    4. 8.4 Device Functional Modes
      1. 8.4.1 Normal Operating Mode
  9. Application and Implementation
    1. 9.1 Application Information
    2. 9.2 Typical Applications
      1. 9.2.1 100-kΩ Gain Transimpedance Design
        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 Noninverting Gain of 3 V/V
      3. 9.2.3 High-Input Impedance (Hi-Z), High-Gain Signal Front-End
        1. 9.2.3.1 Design Requirements
        2. 9.2.3.2 Detailed Design Procedure
        3. 9.2.3.3 Application Curves
      4. 9.2.4 Low-Cost, Low Side, High-Speed Current Sensing
        1. 9.2.4.1 Design Requirements
        2. 9.2.4.2 Detailed Design Procedure
        3. 9.2.4.3 Application Curves
  10. 10Power Supply Recommendations
  11. 11Layout
    1. 11.1 Layout Guidelines
    2. 11.2 Layout Examples
  12. 12Device and Documentation Support
    1. 12.1 Device Support
      1. 12.1.1 Development Support
    2. 12.2 Documentation Support
      1. 12.2.1 Related Documentation
    3. 12.3 Receiving Notification of Documentation Updates
    4. 12.4 Support Resources
    5. 12.5 Trademarks
    6. 12.6 Electrostatic Discharge Caution
    7. 12.7 Glossary
  13. 13Mechanical, Packaging, and Orderable Information

Package Options

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

Detailed Design Procedure

To achieve a SNR of greater than 40 dB for signals from 300 µVrms to 30 mV the front-end stage has two gain settings: 6 V/V and 31 V/V. The SW (switch, relay, or analog mux) can be dynamically toggled to ensure maximum sensitively to the receiving signal. The OPAx607-Q1 devices prove to be an attractive solution for this front-end signal chain because of the right balance of low noise and high input impedance. The ultrasonic sensors (for example, piezo crystal) have high output impedance. The OPAx607-Q1 devices have an input bias current of 20 pA (maximum). This small bias current results in reduced distortion and signal loss across the source impedance when compared with a bipolar amplifier with input bias currents in the range of a few hundreds of nano-amperes. The OPAx607-Q1's high-gain front-end is followed by a narrowband band-pass filter that is tuned to a 200-kHz center frequency. The narrowband filter is designed using the OPA837. OPA837 can be used as a variable gain mux / PGA as shown in TIDA-01565. In this application section the OPA837-based band-pass filter was designed using the techniques mentioned in the Filter Design in Thirty Seconds application report.

Figure 9-11 shows the frequency response of circuit in Figure 9-9. As shown in Figure 9-11, the frequency response is a high-Q factor band-pass filter centered around 200 kHz. Designing such a high-Q band-pass filter helps eliminate white band noise along with other interferences present in the circuitry, resulting in a high SNR signal chain. The OPAx607-Q1's front-end combined with the OPA837-based band-pass filter help to achieve a total gain of 33 dB (44 V/V) or 50 dB (316 V/V) based on the SW (switch) position.