SNOS748F September   1999  – December 2025 LMC7221

PRODUCTION DATA  

  1.   1
  2. 1Features
  3. 2Applications
  4. 3Description
  5. 4Specifications
    1. 4.1 Absolute Maximum Ratings
    2. 4.2 Operating Ratings
    3. 4.3 Electrical Characteristics: 2.7 V
    4. 4.4 Electrical Characteristics: 5.0 V and 15.0 V
    5. 4.5 Leakage Characteristics
    6. 4.6 AC Electrical Characteristics
    7. 4.7 Typical Characteristics
  6. 5Application and Implementation
    1. 5.1 Application Information
      1. 5.1.1  Benefits of the LMC7221 Tiny Comparator
        1. 5.1.1.1  Size
        2. 5.1.1.2  Height
        3. 5.1.1.3  Simplified Board Layout
        4. 5.1.1.4  Low Supply Current
        5. 5.1.1.5  Wide Voltage Range
        6. 5.1.1.6  Digital Outputs Representing Signal Level
        7. 5.1.1.7  Open Drain Output
        8. 5.1.1.8  Driving LEDs (Light Emitting Diodes)
        9. 5.1.1.9  Input Range to Beyond Rail to Rail
        10. 5.1.1.10 Zero Crossing Detector
        11. 5.1.1.11 Low Input Currents and High Input Impedance
        12. 5.1.1.12 Direct Sensor Interfacing
      2. 5.1.2  Low Voltage Operation
      3. 5.1.3  Open Drain Output
        1. 5.1.3.1 Output Stage
      4. 5.1.4  Output Short Circuit Current
      5. 5.1.5  Input Protection
      6. 5.1.6  Layout Considerations
      7. 5.1.7  Push-Pull Outputs, Dual Versions
      8. 5.1.8  Additional 5-Pin SOT-23 Tiny Devices
      9. 5.1.9  Spice Macromodel
      10. 5.1.10 Device and Documentation Support
        1. 5.1.10.1 Receiving Notification of Documentation Updates
        2. 5.1.10.2 Support Resources
        3. 5.1.10.3 Trademarks
        4. 5.1.10.4 Electrostatic Discharge Caution
        5. 5.1.10.5 Glossary
  7. 6Device and Documentation Support
    1. 6.1 Receiving Notification of Documentation Updates
    2. 6.2 Support Resources
    3. 6.3 Trademarks
    4. 6.4 Electrostatic Discharge Caution
    5. 6.5 Glossary
  8. 7Revision History
  9. 8Mechanical, Packaging, and Orderable Information

5.1.3.1 Output Stage

LMC7221 LMC7211 Output StageFigure 5-2 LMC7211 Output Stage
LMC7221 LMC7221 Output StageFigure 5-3 LMC7221 Output Stage

Figure 5-2 and Figure 5-3 shows the difference between push-pull output and open drain output.

Push pull outputs will have a conventional high or low digital output, the same as a logic gate. Low will be the negative supply rail (usually ground) and high will be the positive supply rail.

This is useful if the chips you are interfacing to run on the same supply voltage as the comparator. An example would be an all +5 V system.

Open drain outputs will only pull low—for the high output they depend on an external pull-up resistor. This can pull up to a voltage higher or lower than the comparator supply voltage. This voltage can be as high as 15 V. This makes the open drain parts useful in mixed voltage systems. An example would be where the comparator runs at 5 V and the logic circuits are at 3.3 V. The pull-up resistor would go to the 3.3 V supply.

Open drain outputs are the CMOS equivalent of open collector outputs.