SNOA993A June   2018  – July 2021 LDC2112 , LDC2114 , LDC3114 , LDC3114-Q1

 

  1.   Trademarks
  2. 1Introduction
  3. 2Scan Rate and Sampling Interval
    1. 2.1 Low Power Mode and Normal Power Mode
    2. 2.2 Button Sequencing and Error Handling
  4. 3Data Polarity and Timeout
    1. 3.1 Button Timeout
  5. 4Internal Algorithms Overview
  6. 5Baseline Tracking
    1. 5.1 Baseline Increment
    2. 5.2 Baseline Tracking Reset
    3. 5.3 Button Actuation Time
    4. 5.4 BTPAUSE
    5. 5.5 Fast Tracking Factor
  7. 6Gain, Hysteresis, and Threshold
    1. 6.1 Threshold and Hysteresis
  8. 7Multi-Button Algorithms
    1. 7.1 Max Win
    2. 7.2 Anti-Common Mode
    3. 7.3 Anti-Twist Factor
    4. 7.4 Anti-Deform Factor
  9. 8Summary
  10. 9Revision History

6 Gain, Hysteresis, and Threshold

Each channel has a dedicated gain setting (GAINx). The Gain setting can be adjusted from an effective 1x to 232x, in 64 steps. Throughout this document, the value programmed into the register is referred to as GAINx, and the effective gain value that is applied by the algorithm is referred to as the Gain Factorx. The steps are logarithmically spaced, with each increment in the GAINx field increasing the Gain Factor by ~9%. Using a lower Gain Factorx reduces the sensitivity to environmental shifts. The gain is applied to net code, which is the raw measured value with the baseline tracking subtracted.

GUID-A7212CA7-527C-494D-A5A9-26FBE97EB95E-low.pngFigure 6-1 LDC211x and LDC3114 Gain Factor vs. Programmed Register Field Setting

The effective Net Code shift to a fast stimuli is:

NET_CODEx = 0.013 × Gain_Factorx × ΔƒSENSOR

Where ΔƒSENSOR is in PPM