SNVSBF4 November   2019 LDC1001-Q1

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
    1.     Typical Application — Axial Distance Sensing
  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 Timing Requirements
    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 Inductive Sensing
      2. 7.3.2 Measuring Parallel Resonance Impedance and Inductance With LDC1001-Q1
        1. 7.3.2.1 Measuring Inductance
          1. 7.3.2.1.1 Example
    4. 7.4 Device Functional Modes
      1. 7.4.1 INTB Pin Modes
        1. 7.4.1.1 Comparator Mode
        2. 7.4.1.2 Wake-Up Mode
        3. 7.4.1.3 DRDYB Mode
    5. 7.5 Programming
      1. 7.5.1 Digital Interface
        1. 7.5.1.1 SPI Description
        2. 7.5.1.2 Extended SPI Transactions
    6. 7.6 Register Map
      1. 7.6.1 Register Description
        1. 7.6.1.1  Revision ID (offset = 0x00) [reset = 0x80]
          1. Table 2. Revision ID Field Descriptions
        2. 7.6.1.2  Rp_MAX (offset = 0x01) [reset = 0x0E]
          1. Table 3. Rp_MAX Field Descriptions
        3. 7.6.1.3  Rp_MIN (offset = 0x02) [reset = 0x14]
          1. Table 4. Rp_MIN Field Descriptions
        4. 7.6.1.4  Sensor Frequency (offset = 0x03) [reset = 0x45]
          1. Table 5. Sensor Frequency Field Descriptions
        5. 7.6.1.5  LDC Configuration (offset = 0x04) [reset = 0x1B]
          1. Table 6. LDC Configuration Field Descriptions
        6. 7.6.1.6  Clock Configuration (offset = 0x05) [reset = 0x01]
          1. Table 7. Clock Configuration Field Descriptions
        7. 7.6.1.7  Comparator Threshold High LSB (offset = 0x06) [reset = 0xFF]
          1. Table 8. Comparator Threshold High LSB Field Descriptions
        8. 7.6.1.8  Comparator Threshold High MSB (offset = 0x07) [reset = 0xFF]
          1. Table 9. Comparator Threshold High MSB Field Descriptions
        9. 7.6.1.9  Comparator Threshold Low LSB (offset = 0x08) [reset = 0x00]
          1. Table 10. Comparator Threshold Low LSB Field Descriptions
        10. 7.6.1.10 Comparator Threshold Low MSB (offset = 0x09) [reset = 0x00]
          1. Table 11. Comparator Threshold Low MSB Field Descriptions
        11. 7.6.1.11 INTB Pin Configuration (offset = 0x0A) [reset = 0x00]
          1. Table 12. INTB Pin Configuration Field Descriptions
        12. 7.6.1.12 Power Configuration (offset = 0x0B) [reset = 0x00]
          1. Table 13. Power Configuration Field Descriptions
        13. 7.6.1.13 Status (offset = 0x20) [reset = NA]
          1. Table 14. Status Field Descriptions
        14. 7.6.1.14 Proximity Data LSB (offset = 0x21) [reset = NA]
          1. Table 15. Proximity Data LSB Field Descriptions
        15. 7.6.1.15 Proximity Data MSB (offset = 0x22) [reset = NA]
          1. Table 16. Proximity Data MSB Field Descriptions
        16. 7.6.1.16 Frequency Counter LSB (offset = 0x23) [reset = NA]
          1. Table 17. Frequency Counter LSB Field Descriptions
        17. 7.6.1.17 Frequency Counter Mid-Byte (offset = 0x24) [reset = NA]
          1. Table 18. Frequency Counter Mid-Byte Field Descriptions
        18. 7.6.1.18 Frequency Counter MSB (offset = 0x25) [reset = NA]
          1. Table 19. Frequency Counter MSB Field Descriptions
  8. 8 Application and Implementation
    1. 8.1 Application Information
      1. 8.1.1 Calculation of Rp_Min and Rp_Max
        1. 8.1.1.1 Rp_MAX
        2. 8.1.1.2 Rp_MIN
      2. 8.1.2 Output Data Rate
        1. 8.1.2.1 Example
      3. 8.1.3 Selecting a Filter Capacitor (CFA and CFB Pins)
    2. 8.2 Typical Application
      1. 8.2.1 Design Requirements
      2. 8.2.2 Detailed Design Procedure
        1. 8.2.2.1 Sensor and Target
        2. 8.2.2.2 Calculating a Sensor Capacitor
        3. 8.2.2.3 Selecting a Filter Capacitor
        4. 8.2.2.4 Setting Rp_MIN and Rp_MAX
        5. 8.2.2.5 Calculating Minimum Sensor Frequency
      3. 8.2.3 Application Curves
  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 Receiving Notification of Documentation Updates
    2. 11.2 Support Resources
    3. 11.3 Trademarks
    4. 11.4 Electrostatic Discharge Caution
    5. 11.5 Glossary
  12. 12Mechanical, Packaging, and Orderable Information

Package Options

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

7.1 Overview

The LDC1001-Q1 device is an inductance-to-digital converter that simultaneously measures the impedance and resonant frequency of an LC resonator. The device accomplishes this task by regulating the oscillation amplitude in a closed-loop configuration to a constant level, while monitoring the energy dissipated by the resonator. By monitoring the amount of power injected into the resonator, the LDC1001-Q1 device can determine the value of RP. When the value is determined, the device returns this as a digital value which is inversely proportional to RP. In addition, the LDC1001-Q1 device also measure the oscillation frequency of the LC circuit. This frequency is used to determine the inductance of the LC circuit. The device outputs a digital value that is inversely proportional to frequency.

The threshold detector block provides a comparator with hysteresis. With the threshold registers programed and comparator enabled, the proximity data register is compared with threshold registers and INTB pin indicates the output.

The device has a simple 4-wire SPI interface. The INTB pin provides multiple functions which are programmable with SPI.

The device has separate analog and I/O supplies. The analog supply operates at 5 V and the I/O operates at 1.8 to 5 V. The integrated LDO requires a 56-nF capacitor connected from the CLDO pin to GND.