SBOSAM3A July   2025  – August 2025 INA600

PRODMIX  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Device Comparison Table
  6. 5 Pin Configuration and Functions
  7. 6 Specifications
    1. 6.1 Absolute Maximum Ratings
    2. 6.2 ESD Ratings
    3. 6.3 Recommended Operating Conditions
    4. 6.4 Thermal Information
    5. 6.5 Electrical Characteristics - INA600A
    6. 6.6 Electrical Characteristics - INA600B
    7. 6.7 Electrical Characteristics - INA600F
    8. 6.8 Typical Characteristics
  8. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1 Gain Options and Resistors
        1. 7.3.1.1 Gain Error and Drift
      2. 7.3.2 Input Common-Mode Voltage Range
      3. 7.3.3 EMI Rejection
      4. 7.3.4 Typical Specifications and Distributions
      5. 7.3.5 Electrical Overstress
    4. 7.4 Device Functional Modes
  9. 8 Application and Implementation
    1. 8.1 Application Information
      1. 8.1.1 Reference Pin
    2. 8.2 Typical Applications
      1. 8.2.1 48V Battery Monitoring Using Difference Amplifier
        1. 8.2.1.1 Design Requirements
        2. 8.2.1.2 Detailed Design Procedure
        3. 8.2.1.3 Application Curves
    3. 8.3 Power Supply Recommendations
    4. 8.4 Layout
      1. 8.4.1 Layout Guidelines
      2. 8.4.2 Layout Example
  10. 9 Device and Documentation Support
    1. 9.1 Device Support
      1. 9.1.1 Development Support
        1. 9.1.1.1 PSpice® for TI
    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
  11. 10Revision History
  12. 11Mechanical, Packaging, and Orderable Information

8.2.1.2 Detailed Design Procedure

This section provides basic calculations for the INA600B difference amplifier with respect to the given design requirements.

Firstly, the 48V battery voltage must be attenuated and interfaced to ADC reference voltage of 5V. This requires a G = 1/10 or 0.10V/V and therefore the INA600B is chosen for the application.

Equation 1. G a i n =   V A D C V B A T =   5 48 is approximately 0.10    

The maximum common-mode range of INA600 in a gain of 1/10 at 5V supply is given to be (V–) + 55V from the INA600B Electrical Characteristics table.

This is well within the requirements for sensing 48V battery voltage and the common-mode rejection ratio (CMRR) referred to output is a minimum of 95dB as per INA600B Electrical Characteristics table. This corresponds to a attenuation factor of 1 56234 . This helps attenuate the 100mV common-mode error shown in the Figure 8-2 to just under 2μV.

When referring to the INA600B output, Equation 2 calculates the common-mode error, RTO to approximately 2µV.

Equation 2. C M E r r _ R T O = 100 m V 56231   ≅ 2 μ V

Next, INA600B has input impedance of 1.2MΩ as per the Electrical Characteristics table. Assuming a full battery voltage of 48V, the input current through the resistor is calculated as:

Equation 3.   I R I N =   V B A T R I N =   48 1.20 M = 40 μ A    

This input current through the resistor adds to the amplifier quiescent current of 65μA resulting in a total current consumption of 105μA, which meets the design requirement of 125μA.

Equation 4. I t o t a l =   I R I N +   I Q

The next step is to calculate the other error sources in the application. Maximum gain error and offset error as per Electrical Characteristics table are 0.05% and 3.0mV for the Gain = 0.2V/V.

Equation 5. T o t a l   E r r o r =   ( 0.0005 × 48 ) 2 +   0.0030 2 = 24.2 m V

For an 8-bit, 5V ADC, VLSB is calculated as:

Equation 6. V L S B =   5 2 8 = 19.5 m V

The total error of 24.2mV that was calculated is approximately 1.25LSB of ADC full scale voltage of 5V and hence achieves almost 8 bits (approximately 7.998) of ENOB, comfortably meeting the requirement of 7.5 bits.

Note that the errors across temperature are not calculated here but can be easily included in the error analysis based on the drift specifications provided in the Electrical Characteristics table as per the temperature requirements of the application. These drift errors and noise often do not heavily affect the performance at 8-bit accuracy levels. Finally, calibration of offset and gain error can improve the accuracy beyond 10 to 12 bits as these factors can be the major sources of error in the application.