SNOSCY9A December   2014  – March 2018 LDC1612 , LDC1614

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
    1.     Device Images
      1.      Simplified Schematic
      2.      Measurement Precision vs. Target Distance
  4. 4 Revision History
  5. 5 Pin Configuration and Functions
    1.     Pin Functions
  6. 6 Specifications
    1. 6.1 Absolute Maximum Ratings
    2. 6.2 ESD Ratings
    3. 6.3 Recommended Operating Conditions
    4. 6.4 Thermal Information
    5. 6.5 Electrical Characteristics
    6. 6.6 Switching Characteristics - I2C
    7. 6.7 Typical Characteristics
  7. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1 Multi-Channel and Single Channel Operation
      2. 7.3.2 Adjustable Conversion Time
      3. 7.3.3 Sensor Startup and Glitch Configuration
      4. 7.3.4 Reference Clock
      5. 7.3.5 Sensor Current Drive Control
      6. 7.3.6 Device Status Monitoring
    4. 7.4 Device Functional Modes
      1. 7.4.1 Startup Mode
      2. 7.4.2 Sleep Mode (Configuration Mode)
      3. 7.4.3 Normal (Conversion) Mode
      4. 7.4.4 Shutdown Mode
        1. 7.4.4.1 Reset
    5. 7.5 Programming
      1. 7.5.1 I2C Interface Specifications
      2. 7.5.2 Pulses on I2C
      3. 7.5.3 Multi Register Data Readback
    6. 7.6 Register Maps
      1. 7.6.1  Register List
      2. 7.6.2  Address 0x00, DATA0_MSB
        1. Table 1. Address 0x00, DATA0_MSB Field Descriptions
      3. 7.6.3  Address 0x01, DATA0_LSB
        1. Table 2. Address 0x01 DATA0_LSB Field Descriptions
      4. 7.6.4  Address 0x02, DATA1_MSB
        1. Table 3. Address 0x02, DATA1_MSB Field Descriptions
      5. 7.6.5  Address 0x03, DATA1_LSB
        1. Table 4. Address 0x03, DATA1_LSB Field Descriptions
      6. 7.6.6  Address 0x04, DATA2_MSB (LDC1614 only)
        1. Table 5. Address 0x04, DATA2_MSB Field Descriptions
      7. 7.6.7  Address 0x05, DATA2_LSB (LDC1614 only)
        1. Table 6. Address 0x05 DATA2_LSB Field Descriptions
      8. 7.6.8  Address 0x06, DATA3_MSB (LDC1614 only)
        1. Table 7. Address 0x06, DATA3_MSB Field Descriptions
      9. 7.6.9  Address 0x07, DATA3_LSB (LDC1614 only)
        1. Table 8. Address 0x07 DATA3_LSB Field Descriptions
      10. 7.6.10 Address 0x08, RCOUNT0
        1. Table 9. Address 0x08, RCOUNT0 Field Descriptions
      11. 7.6.11 Address 0x09, RCOUNT1
        1. Table 10. Address 0x09, RCOUNT1 Field Descriptions
      12. 7.6.12 Address 0x0A, RCOUNT2 (LDC1614 only)
        1. Table 11. Address 0x0A, RCOUNT2 Field Descriptions
      13. 7.6.13 Address 0x0B, RCOUNT3 (LDC1614 only)
        1. Table 12. Address 0x0B, RCOUNT3 Field Descriptions
      14. 7.6.14 Address 0x0C, OFFSET0
        1. Table 13. OFFSET0 Field Descriptions
      15. 7.6.15 Address 0x0D, OFFSET1
        1. Table 14. Address 0x0D, OFFSET1 Field Descriptions
      16. 7.6.16 Address 0x0E, OFFSET2 (LDC1614 only)
        1. Table 15. Address 0x0E, OFFSET2 Field Descriptions
      17. 7.6.17 Address 0x0F, OFFSET3 (LDC1614 only)
        1. Table 16. Address 0x0F, OFFSET3 Field Descriptions
      18. 7.6.18 Address 0x10, SETTLECOUNT0
        1. Table 17. Address 0x10, SETTLECOUNT0 Field Descriptions
      19. 7.6.19 Address 0x11, SETTLECOUNT1
        1. Table 18. Address 0x11, SETTLECOUNT1 Field Descriptions
      20. 7.6.20 Address 0x12, SETTLECOUNT2 (LDC1614 only)
        1. Table 19. Address 0x12, SETTLECOUNT2 Field Descriptions
      21. 7.6.21 Address 0x13, SETTLECOUNT3 (LDC1614 only)
        1. Table 20. Address 0x13, SETTLECOUNT3 Field Descriptions
      22. 7.6.22 Address 0x14, CLOCK_DIVIDERS0
        1. Table 21. Address 0x14, CLOCK_DIVIDERS0 Field Descriptions
      23. 7.6.23 Address 0x15, CLOCK_DIVIDERS1
        1. Table 22. Address 0x15, CLOCK_DIVIDERS1 Field Descriptions
      24. 7.6.24 Address 0x16, CLOCK_DIVIDERS2 (LDC1614 only)
        1. Table 23. Address 0x16, CLOCK_DIVIDERS2 Field Descriptions
      25. 7.6.25 Address 0x17, CLOCK_DIVIDERS3 (LDC1614 only)
        1. Table 24. Address 0x17, CLOCK_DIVIDERS3
      26. 7.6.26 Address 0x18, STATUS
        1. Table 25. Address 0x18, STATUS Field Descriptions
      27. 7.6.27 Address 0x19, ERROR_CONFIG
        1. Table 26. Address 0x19, ERROR_CONFIG
      28. 7.6.28 Address 0x1A, CONFIG
        1. Table 27. Address 0x1A, CONFIG Field Descriptions
      29. 7.6.29 Address 0x1B, MUX_CONFIG
        1. Table 28. Address 0x1B, MUX_CONFIG Field Descriptions
      30. 7.6.30 Address 0x1C, RESET_DEV
        1. Table 29. Address 0x1C, RESET_DEV Field Descriptions
      31. 7.6.31 Address 0x1E, DRIVE_CURRENT0
        1. Table 30. Address 0x1E, DRIVE_CURRENT0 Field Descriptions
      32. 7.6.32 Address 0x1F, DRIVE_CURRENT1
        1. Table 31. Address 0x1F, DRIVE_CURRENT1 Field Descriptions
      33. 7.6.33 Address 0x20, DRIVE_CURRENT2 (LDC1614 only)
        1. Table 32. Address 0x20, DRIVE_CURRENT2 Field Descriptions
      34. 7.6.34 Address 0x21, DRIVE_CURRENT3 (LDC1614 only)
        1. Table 33. DRIVE_CURRENT3 Field Descriptions
      35. 7.6.35 Address 0x7E, MANUFACTURER_ID
        1. Table 34. Address 0x7E, MANUFACTURER_ID Field Descriptions
      36. 7.6.36 Address 0x7F, DEVICE_ID
        1. Table 35. Address 0x7F, DEVICE_ID Field Descriptions
  8. 8 Application and Implementation
    1. 8.1 Application Information
      1. 8.1.1 Conductive Objects in a Time-Varying EM Field
      2. 8.1.2 L-C Resonators
      3. 8.1.3 Multi-Channel and Single Channel Operation
        1. 8.1.3.1 Data Offset
      4. 8.1.4 Sensor Conversion Time
        1. 8.1.4.1 Settling Time
        2. 8.1.4.2 Sensor Activation
      5. 8.1.5 Sensor Current Drive Configuration
        1. 8.1.5.1 Inactive Channel Sensor Connections
        2. 8.1.5.2 Automatic IDRIVE Setting with RP_OVERRIDE_EN
        3. 8.1.5.3 Determining Sensor IDRIVE for an Unknown Sensor RP Using an Oscilloscope
        4. 8.1.5.4 Sensor Auto-Calibration Mode
        5. 8.1.5.5 Channel 0 High Current Drive
      6. 8.1.6 Clocking Architecture
      7. 8.1.7 Input Deglitch Filter
      8. 8.1.8 Device Status Registers
      9. 8.1.9 Multi-Channel Data Readback
    2. 8.2 Typical Application
      1. 8.2.1 System Sensing Functionality
      2. 8.2.2 Example Application
      3. 8.2.3 Design Requirements
      4. 8.2.4 Detailed Design Procedure
      5. 8.2.5 Recommended Initial Register Configuration Values
      6. 8.2.6 Application Curves
      7. 8.2.7 Inductor Self-Resonant Frequency
  9. 9 Power Supply Recommendations
  10. 10Layout
    1. 10.1 Layout Guidelines
    2. 10.2 Layout Example
  11. 11Device and Documentation Support
    1. 11.1 Device Support
      1. 11.1.1 Development Support
    2. 11.2 Documentation Support
      1. 11.2.1 Related Documentation
    3. 11.3 Related Links
    4. 11.4 Receiving Notification of Documentation Updates
    5. 11.5 Community Resources
    6. 11.6 Trademarks
    7. 11.7 Electrostatic Discharge Caution
    8. 11.8 Glossary
  12. 12Mechanical, Packaging, and Orderable Information

Package Options

Mechanical Data (Package|Pins)
Thermal pad, mechanical data (Package|Pins)
Orderable Information

8.1.3 Multi-Channel and Single Channel Operation

The multi-channel package of the LDC enables the user to save board space and support flexible system design. For example, temperature drift can often cause a shift in component values, resulting in a shift in resonant frequency of the sensor. Using a second sensor as a reference or in a differential configuration provides the capability to cancel out temperature shifts and other environmental variations. When operated in multi-channel mode, the LDC sequentially samples the selected channels - only one channel is active at any time while the other selected channels are held in an inactive state. In single channel mode, the LDC samples a single channel, which is selectable. Refer to Inactive Channel Sensor Connections for more details on inactive channels.

Inactive channels have the corresponding INAx and INBx pins tied to ground. The following table shows the registers and values that are used to configure either multi-channel or single channel modes.

LDC1612 LDC1614 sequential_mode_ch_seq_snoscy9.gifFigure 53. Multi-Channel Mode Sequencing
LDC1612 LDC1614 single_ch_conv_mode_snoscy9.gifFigure 54. Single-Channel Mode Sequencing

Table 36. Single and Multi-Channel Configuration Registers

MODE REGISTER FIELD VALUE(1)
Single channel CONFIG, addr 0x1A ACTIVE_CHAN [15:14] 00 = chan 0
01 = chan 1
10 = chan 2
11 = chan 3
MUX_CONFIG addr 0x1B AUTOSCAN_EN [15] 0 = continuous conversion on a single channel (default)
Multi-channel MUX_CONFIG addr 0x1B AUTOSCAN_EN [15] 1 = continuous conversion on multiple channels
MUX_CONFIG addr 0x1B RR_SEQUENCE [14:13] 00 = Ch0, Ch 1
01 = Ch0, Ch 1, Ch 2
10 = Ch0, CH1, Ch2, Ch3
(1) Channels 2 and 3 are only available for LDC1614

The digitized sensor measurement for each channel (DATAx) represents the ratio of the sensor frequency to the reference frequency.

With FREF_DIVIDERx and FIN_DIVIDERx set to 1, the sensor frequency can be calculated from:

Equation 4. LDC1612 LDC1614 eq17_snoscy9.gif

The following table illustrates the registers that contain the fixed point sample values for each channel. The conversion result for each channel, DATAx, can be calculated with:

Equation 5. DATAx = DATAx_MSB×65536 + DATAx_LSB

Table 37. LDC1612/1614 Sample Data Registers

CHANNEL(2) REGISTER(1) FIELD NAME [ BITS(S) ] VALUE(3)(4)
0 DATA0_MSB, addr 0x00 DATA0 [27:16] 12 MSBs of the 28 bit conversion for Channel 0
DATA0_LSB addr 0x01 DATA0 [15:0] 16 LSBs of the 28 bit conversion for Channel 0
1 DATA1_MSB, addr 0x02 DATA1 [27:16] 12 MSBs of the 28 bit conversion for Channel 1
DATA1_LSB, addr 0x03 DATA1 [15:0] 16 LSBs of the 28 bit conversion for Channel 1
2 DATA1_MSB, addr 0x04 DATA2 [27:16] 12 MSBs of the 28 bit conversion for Channel 2
DATA1_LSB, addr 0x05 DATA2 [15:0] 16 LSBs of the 28 bit conversion for Channel 2
3 DATA1_MSB, addr 0x06 DATA3 [27:16] 12 MSBs of the 28 bit conversion for Channel 3
DATA1_LSB, addr 0x07 DATA3 [15:0] 16 LSBs of the 28 bit conversion for Channel 0
(1) The DATAx_MSB register must always be read prior to the DATAx_LSB register of the same channel to ensure data coherency.
(2) Channels 2 and 3 available only in LDC1614.
(3) A DATAx value of 0x000'0000 indicates an under-range condition for LDC1612/LDC1614 corresponding channel
(4) A DATAx value of 0xFFF'FFFF indicates an over-range condition for LDC1612/LDC1614 corresponding channel