SBOSAF3D November   2023  – May 2026 TMCS1126

PRODUCTION DATA  

  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-Related Certifications
    8. 6.8  Safety Limiting Values
    9. 6.9  Electrical Characteristics
    10. 6.10 Typical Characteristics
      1. 6.10.1 Insulation Characteristics Curves
  8. 7 Parameter Measurement Information
    1. 7.1 Accuracy Parameters
      1. 7.1.1 Sensitivity Error
      2. 7.1.2 Offset Error and Offset Error Drift
      3. 7.1.3 Nonlinearity Error
      4. 7.1.4 Power Supply Rejection Ratio
      5. 7.1.5 Common-Mode Rejection Ratio
      6. 7.1.6 External Magnetic Field Errors
    2. 7.2 Transient Response Parameters
      1. 7.2.1 CMTI, Common-Mode Transient Immunity
    3. 7.3 Safe Operating Area
      1. 7.3.1 Continuous DC or Sinusoidal AC Current
      2. 7.3.2 Repetitive Pulsed Current SOA
      3. 7.3.3 Single Event Current Capability
  9. 8 Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1 Current Input
      2. 8.3.2 Input Isolation
      3. 8.3.3 Ambient Field Rejection
      4. 8.3.4 High-Precision Signal Chain
        1. 8.3.4.1 Temperature Stability
        2. 8.3.4.2 Lifetime and Environmental Stability
      5. 8.3.5 Internal Reference Voltage
      6. 8.3.6 Current-Sensing Measurable Ranges
      7. 8.3.7 Overcurrent Detection
        1. 8.3.7.1 Setting The User Configurable Overcurrent Threshold
          1. 8.3.7.1.1 Setting Overcurrent Threshold Using Power Supply Voltage
          2. 8.3.7.1.2 Setting Overcurrent Threshold Using Internal Reference Voltage
          3. 8.3.7.1.3 Setting Overcurrent Threshold Example
        2. 8.3.7.2 Overcurrent Output Response
    4. 8.4 Device Functional Modes
      1. 8.4.1 Power-Down Behavior
  10. 9 Application and Implementation
    1. 9.1 Application Information
      1. 9.1.1 Total Error Calculation Examples
        1. 9.1.1.1 Room-Temperature Error Calculations
        2. 9.1.1.2 Full-Temperature Range Error Calculations
    2. 9.2 Typical Application
      1. 9.2.1 Design Requirements
      2. 9.2.2 Detailed Design Procedure
      3. 9.2.3 Application Curve
    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 Nomenclature
    2. 10.2 Device Support
      1. 10.2.1 Development Support
    3. 10.3 Documentation Support
      1. 10.3.1 Related Documentation
    4. 10.4 Receiving Notification of Documentation Updates
    5. 10.5 Support Resources
    6. 10.6 Trademarks
    7. 10.7 Electrostatic Discharge Caution
    8. 10.8 Glossary
  12. 11Revision History
  13. 12Mechanical, Packaging, and Orderable Information

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9.3 Power Supply Recommendations

The TMCS1126 only requires a power supply (VS) on the low-voltage isolated side, which powers the analog circuitry independent of the isolated current input. VS determines the full-scale output range of the analog output VOUT, and can be supplied with any voltage between 3V and 5.5V. To filter noise in the power-supply path, place a low-ESR decoupling capacitor of 0.1µF between VS and GND pins as close as possible to the supply and ground pins of the device. More decoupling capacitance can be added to compensate for noisy or high-impedance power supplies. When used in extremely noisy environments, ferrite beads can be added close to the supply pin as shown in Figure 9-4 to target and suppress high-frequency noise coupled on to system supply.

TMCS1126 Power Supply Noise FilteringFigure 9-4 Power Supply Noise Filtering

The TMCS1126 power supply VS can be sequenced independently of current flowing through the input. However, there is a power-on delay between VS reaching the recommended operating voltage and the analog output validation. During this power-on time, the output voltage VOUT can transition between GND and VS as the output transfers from a high impedance reset state to the active drive state. If this behavior must be avoided, then provide a stable supply voltage VS for longer than the power-on time prior to applying input current.

Due to the effects of the parasitic capacitance as shown in Figure 7-3, fast voltage edges on the leadframe can couple high frequency voltage content to the low voltage pins on the device. Both the supply voltage and the VOC threshold in TMCS112x devices can experience this ringing and can cause temporary incorrect logic states of the OC pin. For this reason, place additional 10µF capacitors on both VS and VOC for the best comparator performance in noisy environments with fast common mode voltage edges. These additional capacitors help verify that the supply voltage is stable while also stabilizing the threshold of the comparator.

TMCS1126 TMCS11xx Overcurrent Threshold Stability Figure 9-5 TMCS11xx Overcurrent Threshold Stability

When using the additional 10µF capacitors, use a VOC supply with excellent drive strength. When supplying multiple TMCS112x devices with the same external VOC voltage, use the external reference for each TMCS112x as shown in Figure 9-6 or the supply voltage.

TMCS1126 TMCS112x Overcurrent Threshold Stability Figure 9-6 TMCS112x Overcurrent Threshold Stability

For both of these suggestions, R2 needs to be less than 10kΩ to verify ≤10% threshold error due to the internal overcurrent input impedance of 120kΩ. The isolation resistor (R1) for the TMCS112x VREF pin to drive 10µF must be greater than 500Ω to provide reference stability.