TIDUF53 December   2023 DRV8210 , INA350 , MSPM0L1306

 

  1.   1
  2.   Description
  3.   Resources
  4.   Features
  5.   Applications
  6.   6
  7. 1System Description
    1. 1.1 Terminology
    2. 1.2 Key System Specifications
  8. 2System Overview
    1. 2.1 Block Diagram
    2. 2.2 Design Considerations
      1. 2.2.1 System Design Theory
      2. 2.2.2 Bridge Biasing
      3. 2.2.3 INA Stage
      4. 2.2.4 Filter Design
    3. 2.3 Highlighted Products
      1. 2.3.1 MCU-MSPM0L1306
      2. 2.3.2 OPA-LMV324A
      3. 2.3.3 LDO-TPS7A2433
      4. 2.3.4 INA350
      5. 2.3.5 DRV8210
      6. 2.3.6 ATL431LI
  9. 3Hardware, Software, Testing Requirements, and Test Results
    1. 3.1 Hardware Requirements
      1. 3.1.1 System Connection
    2. 3.2 Software Requirements
    3. 3.3 Running the Demonstration
    4. 3.4 Test Results
  10. 4Design and Documentation Support
    1. 4.1 Design Files
      1. 4.1.1 Schematic
      2. 4.1.2 BOM
      3. 4.1.3 PCB Layout Recommendations
    2. 4.2 Tools and Software
    3. 4.3 Documentation Support
    4. 4.4 Support Resources
    5. 4.5 Trademarks
  11. 5About the Author

2.2.3 INA Stage

This reference design allows for two different INA implementations to be used for evaluation. The first one, seen in Figure 2-1, uses the integrated amplifiers of the MSPM0 to form a two amplifier INA with approximately 32 dB of gain as shown in Figure 2-5. For detailed steps of the design process, see the Overcurrent event detection circuit design guide.

Figure 2-2 illustrates the second implementation using the low-cost integrated INA350 with a 3.5-µVPP, 1/f noise and gain settings of 20 V/V or 50 V/V through a gain select pin. The low-cost INA350 or INA351A can be paired with a lower cost MSPM0L1106 if the extra amplifiers are not needed.

At this point, the blood vessel oscillations (0.5 Hz–7 Hz) caused by the heart pumping blood in the order of 100-µV to 300-µV peak-to-peak amplitude, are superimposed on a 15-mV amplitude DC signal going into the INA. The expected output is 750-mV DC pressure range with about 10-mV oscillations.

GUID-20231204-SS0I-KTMB-QL8F-7M9GPF8LVQZF-low.svgFigure 2-5 Two-Amplifier INA Circuit