SBOSAG7 April   2025 TMCS1143

ADVANCE INFORMATION  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Device Comparison
  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 Power Ratings
    6. 6.6 Insulation Specifications
    7. 6.7 Safety Limiting Values
    8. 6.8 Electrical Characteristics
  8. 7 Typical Characteristics
    1. 7.1 Insulation Characteristics Curves
  9. 8 Parameter Measurement Information
    1. 8.1 Accuracy Parameters
      1. 8.1.1 Sensitivity Error
      2. 8.1.2 Offset Error and Offset Error Drift
      3. 8.1.3 Nonlinearity Error
      4. 8.1.4 Power Supply Rejection Ratio
      5. 8.1.5 Common-Mode Rejection Ratio
      6. 8.1.6 External Magnetic Field Errors
    2. 8.2 Transient Response Parameters
      1. 8.2.1 CMTI, Common-Mode Transient Immunity
    3. 8.3 Safe Operating Area
      1. 8.3.1 Continuous DC or Sinusoidal AC Current
      2. 8.3.2 Repetitive Pulsed Current SOA
      3. 8.3.3 Single Event Current Capability
  10. 9 Detailed Description
    1. 9.1 Overview
    2. 9.2 Functional Block Diagram
    3. 9.3 Feature Description
      1. 9.3.1 Current Input
      2. 9.3.2 Ambient Field Rejection
      3. 9.3.3 High-Precision Signal Chain
        1. 9.3.3.1 Temperature Stability
        2. 9.3.3.2 Lifetime and Environmental Stability
      4. 9.3.4 Internal Reference Voltage
      5. 9.3.5 Current-Sensing Measurable Ranges
      6. 9.3.6 Overcurrent Detection
        1. 9.3.6.1 Setting The User Configurable Overcurrent Threshold
          1. 9.3.6.1.1 Setting Overcurrent Threshold Using Power Supply Voltage
          2. 9.3.6.1.2 Setting Overcurrent Threshold Using Internal Reference Voltage
          3. 9.3.6.1.3 Setting Overcurrent Threshold Example
        2. 9.3.6.2 Overcurrent Output Response
      7. 9.3.7 Sensor Diagnostics
        1. 9.3.7.1 Thermal Alert
        2. 9.3.7.2 Sensor Alert
    4. 9.4 Device Functional Modes
      1. 9.4.1 Power-Down Behavior
  11. 10Application and Implementation
    1. 10.1 Application Information
      1. 10.1.1 Total Error Calculation Examples
        1. 10.1.1.1 Room-Temperature Error Calculations
        2. 10.1.1.2 Full-Temperature Range Error Calculations
    2. 10.2 Typical Application
      1. 10.2.1 Design Requirements
      2. 10.2.2 Detailed Design Procedure
      3. 10.2.3 Application Curve
    3. 10.3 Power Supply Recommendations
    4. 10.4 Layout
      1. 10.4.1 Layout Guidelines
      2. 10.4.2 Layout Example
  12. 11Device and Documentation Support
    1. 11.1 Device Nomenclature
    2. 11.2 Device Support
      1. 11.2.1 Development Support
    3. 11.3 Documentation Support
      1. 11.3.1 Related Documentation
    4. 11.4 Receiving Notification of Documentation Updates
    5. 11.5 Support Resources
    6. 11.6 Trademarks
    7. 11.7 Electrostatic Discharge Caution
    8. 11.8 Glossary
  13. 12Revision History
  14. 13Mechanical, Packaging, and Orderable Information
    1. 13.1 Mechanical Data
    2.     PACKAGING INFORMATION
    3. 13.2 Tape and Reel Information

Refer to the PDF data sheet for device specific package drawings

Mechanical Data (Package|Pins)
  • DVF|10
Thermal pad, mechanical data (Package|Pins)

10.2.2 Detailed Design Procedure

The primary design parameter for using the TMCS1143 is the optimum sensitivity variant based on the required measured current levels and the selected supply voltage. Positive and negative currents are measured in this in-line phase current application example, therefore select a bidirectional variant. The TMCS1143 has a precision internal reference voltage that determines the zero current output voltage, VOUT,0A.

The internal reference voltage on TMCS1143Axx variants, with zero current output voltage VOUT,0A = 2.5V is intended for bidirectional current measurements when used with 5V power supplies. The internal reference voltage on TMCS1143Bxx variants, with zero current output voltage VOUT,0A = 1.65V is intended for bidirectional current measurements when used with 3.3V power supplies. Further consideration of noise and integration with an ADC can be explored, but is beyond the scope of this application design example. The TMCS1143 output voltage VOUT is proportional to the input current IIN as defined by Equation 30 with output offset set by VOUT,0A.

Equation 30. VOUT=IIN×S+VOUT,0A

Design of the optimum sensing solution focuses on maximizing the sensitivity of the device while maintaining linear measurements over the required input current range. The TMCS1143 has a linear measurable current range that is constrained by either the positive swing to supply or negative swing to ground. To account for the operating margin, consider the previously defined minimum possible supply voltage VS,min = 4.9V. With the previous parameters, the maximum linear output voltage VOUT,max is defined by Equation 31 and the minimum linear output voltage VOUT,min is defined by Equation 32.

Equation 31. VOUT,max=VS,min-100mV
Equation 32. VOUT,min=100mV

Design parameters for this example application are shown in Table 10-4 along with the calculated output range.

Table 10-4 Example Application Design Parameters
DESIGN PARAMETEREXAMPLE VALUE
VOUT,max4.8V
VOUT,0A2.5V
VOUT,max – VOUT,0A2.3V

These design parameters result in a maximum positive linear output voltage swing of ±2.3V about VOUT,0A = 2.5V..To determine which sensitivity variant of the TMCS1143 most fully uses this linear range, use Equation 33 to calculate the maximum current range for a bidirectional current ±IIN,max.

Equation 33. IIN, max=VOUT,max-VOUT,0AS

where

  • S is the sensitivity of the relevant variant.

Table 10-5 shows the calculation for each gain variant of the TMCS1143 with the appropriate sensitivities.

Table 10-5 Maximum Full-Scale Current Ranges With 2.3V Positive Output Swing
VARIANTSENSITIVITYIIN,max
TMCS1143A3A 15mV/A ±153A
TMCS1143A5A 25mV/A ±92A
TMCS1143A8A 40mV/A ±57.5A
TMCS1143AAA 60mV/A ±38.3A
TMCS1143ACA 100mV/A ±23A

In general, the highest sensitivity variant is selected to provide the lowest maximum input current range that is larger than the required full-scale current range. For the design parameters in this example, the TMCS1143A8A with sensitivity of 40mV/A is the proper selection because the maximum ±57.5A linear measurable range is larger than the required ±50A full-scale current range.