SNOAA35E December   2023  – June 2024 LM2901 , LM2901B , LM2901B-Q1 , LM2903 , LM2903-Q1 , LM2903B , LM2903B-Q1 , LM339 , LM339-N , LM393 , LM393-N , LM393B , LM397 , TL331 , TL331-Q1 , TL331B

 

  1.   1
  2.   Abstract
  3.   Trademarks
  4. 1 Devices Covered in Application Note
    1. 1.1 Base Part Numbers
    2. 1.2 Input Voltage Offset Grades
    3. 1.3 Maximum Supply Voltage
    4. 1.4 High Reliability Options
  5. 2 The New TL331B, TL391B, LM339B, LM393B, LM2901B and LM2903B B Versions
  6. 3 PCN's to Change Classic Die to a New Die Design
    1. 3.1 PCN #1 for Single and Dual (TL331 and LMx93/LM2903)
    2. 3.2 PCN #2 for Single and Dual (TL331 and LMx93/LM2903)
    3. 3.3 PCN For Quad (LMx39/LM2901)
    4. 3.4 Device PCN Summary
    5. 3.5 Determining Die Version Used
      1. 3.5.1 Determine Die Used for Single TL331 and Dual LM293, LM393, and LM2903 - PCN #1 (Ji3)
      2. 3.5.2 Determine Die Used for Single TL331 and Dual LM293, LM393, and LM2903 - PCN #2 (TiB)
      3. 3.5.3 Determine Die Used for Quad LM139, LM239, LM339, and LM2901
  7. 4 Changes to Package Top Markings
  8. 5 Input Considerations
    1. 5.1  Input Stage Schematic – The Classic LM339 Family
    2. 5.2  Input Stage Schematic - New B and TiB Devices
    3. 5.3  Differences Between the Classic, B and Tib Die Devices
    4. 5.4  Input Voltage Range
    5. 5.5  Input Voltage Range vs. Common Mode Voltage Range
    6. 5.6  Reason for Input Range Headroom Limitation
    7. 5.7  Input Voltage Range Feature
    8. 5.8  Both Inputs Above Input Range Behavior
    9. 5.9  Negative Input Voltages
      1. 5.9.1 Maximum Input Current
      2. 5.9.2 Phase Reversal or Inversion
      3. 5.9.3 Protecting Inputs from Negative Voltages
        1. 5.9.3.1 Simple Resistor and Diode Clamp
        2. 5.9.3.2 Voltage Divider with Clamp
          1. 5.9.3.2.1 Split Voltage Divider with Clamp
    10. 5.10 Power-Up Behavior
    11. 5.11 Capacitors and Hysteresis
    12. 5.12 Output to Input Cross-Talk
  9. 6 Output Stage Considerations
    1. 6.1 Output VOL and IOL
    2. 6.2 Pull-Up Resistor Selection
    3. 6.3 Short Circuit Sinking Current
    4. 6.4 Pulling Output Up Above Vcc
    5. 6.5 Negative Voltages Applied to Output
    6. 6.6 Adding Large Filter Capacitors To Output
  10. 7 Power Supply Considerations
    1. 7.1 Supply Bypassing
      1. 7.1.1 Low VCC Guidance
      2. 7.1.2 Split Supply use
  11. 8 General Comparator Usage
    1. 8.1 Unused Comparator Connections
      1. 8.1.1 Do Not Connect Inputs Directly to Ground
      2. 8.1.2 Unused Comparator Input Connections
      3. 8.1.3 Leave Outputs Floating
      4. 8.1.4 Prototyping
  12. 9 PSpice and TINA TI Models
  13. 10Conclusion
  14. 11Related Documentation
    1. 11.1 Related Links
  15. 12Revision History

5.8 Both Inputs Above Input Range Behavior

If both inputs exceed the upper input voltage range (Vin > Vcc - 1.5V), both I1 and I2 are cut off, so Q7 remains off, which allows the base of Q8 to be pulled-up and saturate, pulling the output low.

For the classic Ji1 devices, when the inputs exceed the upper input range, the output goes Low. Because of the Section 5.2 in the Ji3 B and post-PCN single and dual devices, adding an inversion, the B and post-PCN single and dual devices output goes high. The single and dual PCN #2 in TiB adds a clamp to mimic the classic output low behavior.

Because the inputs have no internal clamp or ESD diodes to VCC, the input voltage can go up to a maximum of 36V. If the inputs exceed about VCC-1V, the input blocks current flow due to the reverse biased base-emitter junctions in the input PNP transistors and associated blocking diodes D2 or D4. Current flow is blocked even if VCC equals 0V. If either input or both inputs exceed the maximum 36V VCC rating, junction breakdown can occur. This can lead to permanent device damage per the table notes in the respective device's data sheet Absolute Maximum Ratings table.

If either input is lower than –0.3V with respect to the negative supply, excessive input current can flow in the substrate and the output can display phase reversal, also called inversion. See the Negative Input Voltages in the following section for further information.