SLLSEY7F June   2017  – April 2020 ISO1211 , ISO1212


  1. Features
  2. Applications
  3. Description
    1.     Device Images
      1.          Application Diagram
      2.      ISO121x Devices Reduce Board Temperatures vs Traditional Solutions
  4. Revision History
  5. Pin Configuration and Functions
    1.     Pin Functions
    2.     Pin Functions
  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—DC Specification
    10. 6.10 Switching Characteristics—AC Specification
    11. 6.11 Insulation Characteristics Curves
    12. 6.12 Typical Characteristics
  7. Parameter Measurement Information
    1. 7.1 Test Circuits
  8. Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
    4. 8.4 Device Functional Modes
  9. Application and Implementation
    1. 9.1 Application Information
    2. 9.2 Typical Application
      1. 9.2.1 Sinking Inputs
        1. Design Requirements
        2. Detailed Design Procedure
          1. Setting Current Limit and Voltage Thresholds
          2. Thermal Considerations
          3. Designing for 48-V Systems
          4. Designing for Input Voltages Greater Than 60 V
          5. Surge, ESD, and EFT Tests
          6. Multiplexing the Interface to the Host Controller
          7. Status LEDs
        3. Application Curve
      2. 9.2.2 Sourcing Inputs
      3. 9.2.3 Sourcing and Sinking Inputs (Bidirectional Inputs)
  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 Related Links
    4. 12.4 Receiving Notification of Documentation Updates
    5. 12.5 Community Resource
    6. 12.6 Trademarks
    7. 12.7 Electrostatic Discharge Caution
    8. 12.8 Glossary
  13. 13Mechanical, Packaging, and Orderable Information

Package Options

Refer to the PDF data sheet for device specific package drawings

Mechanical Data (Package|Pins)
  • DBQ|16
Thermal pad, mechanical data (Package|Pins)
Orderable Information

Designing for Input Voltages Greater Than 60 V

The ISO121x devices are rated for 60 V on the SENSE and IN pins with respect to FGND. However, larger voltages on the module input can be supported by dropping extra voltage across an external resistor, RTHR. Because the current drawn by the SENSE and IN pins is well controlled by the built-in current limit, the voltage drop across RTHR is well controlled as well. However, increasing the RTHR resistance also correspondingly raises the voltage transition threshold. An additional resistor, RSHUNT (see Figure 21), provides the flexibility to change the voltage transition thresholds independently of the maximum input voltage. The current through the RSHUNT resistor is less near the voltage transition threshold, but increases with the input voltage, increasing the voltage drop across the RTHR resistor, and preventing the voltage on the ISO121x pins from exceeding 60 V. With the correct value selected for the RTHR and RSHUNT resistors, the voltage transition thresholds and the maximum input voltage supported can be adjusted independently.

A 1-nF or greater CIN capacitor is recommended between the SENSE and FGND pins to slow down the transitions on the SENSE pin, and to prevent overshoot beyond 60 V during transitions.

For more information, refer to the How to Design Isolated Comparators for ±48V, 110V and 240V DC and AC Detection TI TechNote. Use the ISO121x Threshold Calculator for 9V to 300V DC and AC Voltage Detection to estimate the values of voltage transition thresholds, the maximum-allowed module input voltage, and module input current for given values of the RSENSE, RTHR, and RSHUNT resistors.

ISO1211 ISO1212 iso121x-increase-input-voltage-range-with-rshunt.gifFigure 21. Increase ISO121x Input Voltage Range With RSHUNT

Another way to increase the maximum module input voltage without changing the voltage transition thresholds is to use a 60-V Zener diode to limit the voltage on the ISO121x pins to less than 60 V as shown in Figure 22. In this case, when the module input is greater than 60 V, the Zener diode must be designed to sink the additional current, and the RTHR resistor must be designed to drop a higher voltage.

For example, with a 2.5-kΩ RTHR and 560-Ω RSENSE, the voltage transition threshold is 15 V, and the ISO121x input current is 2.25 mA. If the module voltage reaches 100 V, the voltage drop across the RTHR resistor is 40 V, and the current through the Zener diode is approximately 14 mA.

ISO1211 ISO1212 iso121x-increase-input-voltage-range-with-zener-diode.gifFigure 22. Increase ISO121x Input Voltage Range Using a Zener Diode