SBOSAA0C november   2021  – may 2023 INA350

PRODUCTION DATA  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Revision History
  6. 5 Device Comparison Table
  7. 6 Pin Configuration and Functions
  8. 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
  9. 8 Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1 Gain-Setting
        1. 8.3.1.1 Gain Error and Drift
      2. 8.3.2 Input Common-Mode Voltage Range
      3. 8.3.3 EMI Rejection
      4. 8.3.4 Typical Specifications and Distributions
      5. 8.3.5 Electrical Overstress
    4. 8.4 Device Functional Modes
  10. 9 Application and Implementation
    1. 9.1 Application Information
      1. 9.1.1 Reference Pin
      2. 9.1.2 Input Bias Current Return Path
    2. 9.2 Typical Applications
      1. 9.2.1 Resistive-Bridge Pressure Sensor
        1. 9.2.1.1 Design Requirements
        2. 9.2.1.2 Detailed Design Procedure
        3. 9.2.1.3 Application Curves
    3. 9.3 Power Supply Recommendations
    4. 9.4 Layout
      1. 9.4.1 Layout Guidelines
      2. 9.4.2 Layout Example
  11. 10Device and Documentation Support
    1. 10.1 Device Support
      1. 10.1.1 Development Support
        1. 10.1.1.1 PSpice® for TI
    2. 10.2 Documentation Support
      1. 10.2.1 Related Documentation
    3. 10.3 Receiving Notification of Documentation Updates
    4. 10.4 Support Resources
    5. 10.5 Trademarks
    6. 10.6 Electrostatic Discharge Caution
    7. 10.7 Glossary
  12. 11Mechanical, Packaging, and Orderable Information

Package Options

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

9.1.2 Input Bias Current Return Path

The input impedance of the INA350 is extremely high, but a path must be provided for the input bias current of both inputs. This input bias current is typically a few pico amps but at high temperature this can be a few nano amps. High input impedance means that the input bias current changes little with varying input voltage.

For proper operation, input circuitry must provide a path for this input bias current. Figure 9-2 shows various provisions for an input bias current path. Without a bias current path, the inputs float to a potential that exceeds the common-mode range of the INA350, and the input amplifiers saturate. If the differential source resistance is low, the bias current return path connects to one input (as shown in the thermocouple example in Figure 9-2). With a higher source impedance, use two equal resistors to provide a balanced input, with the possible advantages of a lower input offset voltage as a result of bias current, and better high-frequency common-mode rejection.

GUID-D83D9BA5-9686-47A6-AB1A-5F0FA8ED9304-low.gif Figure 9-2 Providing an Input Common-Mode Current Path