SNOA954D November   2019  – June 2021 LDC0851 , LDC1001 , LDC1001-Q1 , LDC1041 , LDC1051 , LDC1101 , LDC1312 , LDC1312-Q1 , LDC1314 , LDC1314-Q1 , LDC1612 , LDC1612-Q1 , LDC1614 , LDC1614-Q1 , LDC2112 , LDC2114 , LDC3114 , LDC3114-Q1

 

  1.   Trademarks
  2. 1LDC Applications
    1. 1.1 Axial Sensing
      1. 1.1.1 Buttons and Keypads
    2. 1.2 Event Counting
    3. 1.3 Other Types of Sensing
  3. 2Inductive Sensing Theory of Operation
  4. 3LDC Device Feature Overview
    1. 3.1 Sample Rate
    2. 3.2 Sensor L Measurement and Reference Frequency
    3. 3.3 Sensor RP Measurement
    4. 3.4 Sensor RP (Current) Drive Capability
    5. 3.5 Switch Output Functionality
    6. 3.6 Sensor Frequency Range
    7. 3.7 Multi-Channel Sensing
    8. 3.8 Power Management
    9. 3.9 Internal Algorithms
  5. 4Device Families
    1. 4.1 Inductive Touch Devices
      1. 4.1.1 Inductive Touch LDC Recommended Applications
    2. 4.2 Multichannel LDC Devices
      1. 4.2.1 Multi-Channel LDC Recommended Applications
      2. 4.2.2 LDC1101
        1. 4.2.2.1 LDC1101 Recommended Applications
      3. 4.2.3 LDC0851
        1. 4.2.3.1 Recommended Applications
  6. 5Summary
  7. 6Revision History

3.8 Power Management

When actively converting, LDC devices typically consume approximately 3 mA, depending mainly on the sensor RP and supply voltage. Some LDC devices have inactive modes in which they consume minimal currents, making them more suitable for power limited applications.

The LDC0851 has a typical shutdown current draw of only 140 nA, and the LDC1312/4 and LDC1612/4 have a typical shutdown current 200 nA, making these devices optimum choices for battery powered systems. Since many applications do not require a very high sample rate, duty-cycling the LDC into an inactive mode whenever possible can provide significant current savings. For example, with an LDC1312 application sampling at 20 sps, the current consumption would be approximately 140 μA. For more Information on managing the power consumption of an LDC device, refer to the TI application note Power Reduction Techniques for the Multichannel LDCs in Inductive Sensing Applications (SNOA949).

Inductive Touch LDC devices such as the LDC2114 and LDC3114 can periodically sample all active channels at a selected scan rate, and then automatically return to an ultra-low power mode without any MCU interaction.