SDAA491 October   2026 TPS25751A , TPS25752A , TPS26750A

 

  1.   1
  2.   Abstract
  3.   Trademarks
  4. 1Introduction
    1. 1.1 What is Liquid Detection and Why is It Needed?
    2. 1.2 Definitions
    3. 1.3 Liquid Detection Method Overview
  5. 2Detailed Description
    1. 2.1 Hardware Implementation and Requirements
      1. 2.1.1 GPIO Hardware Requirements
    2. 2.2 Firmware Implementation and Requirements
      1. 2.2.1 Interrupt Event/Mask/Clear for I2C1 (register 0x14/0x16/0x18)
      2. 2.2.2 GPIO Configuration (register 0x5c)
      3. 2.2.3 Liquid Detection Configuration (register 0x98)
        1. 2.2.3.1 Wait Timing
          1. 2.2.3.1.1 Wait Time in Seconds Non-Liquid [7:0]
          2. 2.2.3.1.2 Wait Time in Seconds Liquid [15:8]
        2. 2.2.3.2 Sample Timing and Retires
          1. 2.2.3.2.1 Sample Time in 10ms No Liquid [19:16]
          2. 2.2.3.2.2 Sample Time in 10ms Liquid [23:20]
          3. 2.2.3.2.3 Liquid Detection Retries Wait Time [27:24]
          4. 2.2.3.2.4 Liquid Detection Retries [31:28]
          5. 2.2.3.2.5 Number of Samples [39:32]
        3. 2.2.3.3 High and Low Threshold Measurements
          1. 2.2.3.3.1 Low Threshold ADC No Liquid [47:40]
          2. 2.2.3.3.2 High Threshold ADC No Liquid [55:48]
          3. 2.2.3.3.3 Low Threshold ADC Liquid [63:56]
          4. 2.2.3.3.4 High Threshold ADC Liquid [71:64]
        4. 2.2.3.4 Enable Liquid Detection [72]
        5. 2.2.3.5 Enable Corrosion Mitigation [73]
        6. 2.2.3.6 Monitor During Attach [74]
        7. 2.2.3.7 Monitor During Unattached [75]
        8. 2.2.3.8 Liquid Pins to Monitor [77:76]
        9. 2.2.3.9 Pulldown Threshold ADC [87:88]
  6. 3Detailed Application Procedure
    1. 3.1 Example Liquid Detection Configuration
    2. 3.2 Application Performance Plots
      1. 3.2.1 Number of Samples Waveform
      2. 3.2.2 Sample Time in No Liquid Waveform
      3. 3.2.3 Sample Time in Liquid Waveform
      4. 3.2.4 Wait Time in No Liquid Waveform
      5. 3.2.5 Wait Time in Liquid Waveform
      6. 3.2.6 Entering Liquid Detection Waveform
      7. 3.2.7 Exiting Liquid Detection Waveform
      8. 3.2.8 Corrosion Mitigation Disabled Waveform
  7. 4Summary
  8. 5References

2.2.3.1 Wait Timing

The sampling interval defines the time between successive measurements during both wet and dry states. This delay is customized via the 'Wait Time' fields to control the timing of the transition on the USB Type-C connector. Higher wait time results in less power consumption but takes more time to enter/exit liquid detected state depending on when the short(s) occurred and when the sampling takes place. Likewise, shorter wait time allows the PD to detect liquid faster but increases the power consumption.