SBOS893D August   2018  – June 2020 INA821

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
    1.     Device Images
      1.      INA821 Simplified Internal Schematic
      2.      Typical Distribution of Input Stage Offset Voltage Drift
  4. 4 Revision History
  5. 5 Device Comparison Table
  6. 6 Pin Configuration and Functions
    1.     Pin Functions
  7. 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: Table of Graphs
    7. 7.7 Typical Characteristics
  8. 8 Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1 Setting the Gain
        1. 8.3.1.1 Gain Drift
      2. 8.3.2 EMI Rejection
      3. 8.3.3 Input Common-Mode Range
      4. 8.3.4 Input Protection
      5. 8.3.5 Operating Voltage
      6. 8.3.6 Error Sources
    4. 8.4 Device Functional Modes
  9. 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 Application
      1. 9.2.1 Design Requirements
      2. 9.2.2 Detailed Design Procedure
      3. 9.2.3 Application Curves
    3. 9.3 Other Application Examples
      1. 9.3.1 Resistance Temperature Detector Interface
  10. 10Power Supply Recommendations
  11. 11Layout
    1. 11.1 Layout Guidelines
    2. 11.2 Layout Example
  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

8.3.2 EMI Rejection

Texas Instruments developed a method to accurately measure the immunity of an amplifier over a broad frequency spectrum extending from 10 MHz to 6 GHz. This method uses an EMI rejection ratio (EMIRR) to quantify the ability of the INA821 to reject EMI. The offset resulting from an input EMI signal is calculated using Equation 2:

Equation 2. INA821 ai_eq003_SBOS792.gif

where

  • VRF_PEAK is the peak amplitude of the input EMI signal.

Figure 56 and Figure 57 show the INA821 EMIRR graph for differential and common-mode EMI rejection across this frequency range. Table 3 lists the EMIRR values for the INA821 at frequencies commonly encountered in real-world applications. Applications listed in Table 3 are centered on or operated near the particular frequency shown. Depending on the end-system requirements, additional EMI filters may be required near the signal inputs of the system. Incorporating known good practices, such as using short traces, low-pass filters, and damping resistors combined with parallel and shielded signal routing, may be required.

INA821 D049_INA821.gif
Figure 56. Common-Mode EMIRR Testing
INA821 D048_INA821.gif
Figure 57. Differential-Mode EMIRR Testing

Table 3. INA821 EMIRR for Frequencies of Interest

FREQUENCY APPLICATION OR ALLOCATION DIFFERENTIAL EMIRR COMMON-MODE EMIRR
400 MHz Mobile radio, mobile satellite, space operation, weather, radar, ultrahigh-frequency (UHF) applications 60 dB 88 dB
900 MHz Global system for mobile communications (GSM) applications, radio communication, navigation, GPS (up to 1.6 GHz), GSM, aeronautical mobile, UHF applications 58 dB 60 dB
1.8 GHz GSM applications, mobile personal communications, broadband, satellite,
L-band (1 GHz to 2 GHz)		 66 dB 89 dB
2.4 GHz 802.11b, 802.11g, 802.11n, Bluetooth®, mobile personal communications, industrial, scientific and medical (ISM) radio band, amateur radio and satellite, S-band (2 GHz to 4 GHz) 73 dB 98 dB
3.6 GHz Radiolocation, aero communication and navigation, satellite, mobile, S-band 99 dB 111 dB
5 GHz 802.11a, 802.11n, aero communication and navigation, mobile communication, space and satellite operation, C-band (4 GHz to 8 GHz) 83 dB 91 dB