SDAA311 June   2026 LM26 , LM26LV , LM56 , LM57 , TMP112 , TMP117 , TMP119 , TMP126 , TMP302 , TMP303 , TMP390 , TMP392 , TMP4718 , TMP4719

 

  1.   1
  2.   Abstract
  3.   Trademarks
  4. 1Introduction
    1. 1.1 Design Workflow
    2. 1.2 TMP390 Window Alert Example
    3. 1.3 TMP390 Cold Trip Example
  5. 2Threshold
    1. 2.1 Hysteresis
    2. 2.2 Response Time
    3. 2.3 Overtemperature Threshold
    4. 2.4 Undertemperature Threshold
    5. 2.5 Window Monitoring Threshold
  6. 3Different Alert Output Types
    1. 3.1 Polarity
    2. 3.2 Comparator/Interrupt Mode
    3. 3.3 Latching Function
    4. 3.4 Fault and Masking Conditions
    5. 3.5 Architecture Type (Push-Pull vs Open Drain)
    6. 3.6 Digital Output
  7. 4Switches
  8. 5Temperature Alert Portfolio
  9. 6Summary
  10. 7References

2.4 Undertemperature Threshold

In contrast to over temperature detection, TI has a selection of device that can be configured for under temperature detection. These devices monitor when the ambient or system temperature drops below a predefined threshold. Differences in the alert signal are defined below:

  1. Trigger Direction: Undertemperature detection activates when the temperature falls below the limit, while over-temperature detection activates when the temperature rises above the limit.
  2. Hysteresis Behavior: In undertemperature detection, hysteresis is applied above the threshold so that the alert clears only after the temperature rises past the hysteresis point. In over-temperature detection, hysteresis is applied below the threshold, so the alert clears after the temperature cools sufficiently.
Undertemperature DetectionFigure 2-5 Undertemperature Detection
Table 2-2 Stages of the Alert Signal
LocationAction
Point 1First temperature conversion to detect thermal event under TLow
Point 2Still below TLow
Point 3Still below TLow Hysteresis, alert will not clear
Point 4Alert clears when temperature rises above TLow+Hysteresis