SNAS648C October   2014  – February 2023 TDC1000

PRODUCTION DATA  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Revision History
  5. 5 Pin Configuration and 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 (1)
    5. 6.5 Electrical Characteristics
    6. 6.6 Timing Requirements
    7. 6.7 Switching Characteristics
    8. 6.8 Typical Characteristics
  7. 7 Parameter Measurement Information
  8. 8 Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1 Transmitter Signal Path
      2. 8.3.2 Receiver Signal Path
      3. 8.3.3 Low Noise Amplifier (LNA)
      4. 8.3.4 Programmable Gain Amplifier (PGA)
      5. 8.3.5 Receiver Filters
      6. 8.3.6 Comparators for STOP Pulse Generation
        1. 8.3.6.1 Threshold Detector and DAC
        2. 8.3.6.2 Zero-Cross Detect Comparator
        3. 8.3.6.3 Event Manager
      7. 8.3.7 Common-Mode Buffer (VCOM)
      8. 8.3.8 Temperature Sensor
        1. 8.3.8.1 Temperature Measurement With Multiple RTDs
        2. 8.3.8.2 Temperature Measurement With a Single RTD
    4. 8.4 Device Functional Modes
      1. 8.4.1 Time-of-Flight Measurement Mode
        1. 8.4.1.1 Mode 0
        2. 8.4.1.2 Mode 1
        3. 8.4.1.3 Mode 2
      2. 8.4.2 State Machine
      3. 8.4.3 TRANSMIT Operation
        1. 8.4.3.1 Transmission Pulse Count
        2. 8.4.3.2 TX 180° Pulse Shift
        3. 8.4.3.3 Transmitter Damping
      4. 8.4.4 RECEIVE Operation
        1. 8.4.4.1 Single Echo Receive Mode
        2. 8.4.4.2 Multiple Echo Receive Mode
      5. 8.4.5 Timing
        1. 8.4.5.1 Timing Control and Frequency Scaling (CLKIN)
        2. 8.4.5.2 TX/RX Measurement Sequencing and Timing
      6. 8.4.6 Time-of-Flight (TOF) Control
        1. 8.4.6.1 Short TOF Measurement
        2. 8.4.6.2 Standard TOF Measurement
        3. 8.4.6.3 Standard TOF Measurement With Power Blanking
        4. 8.4.6.4 Common-Mode Reference Settling Time
        5. 8.4.6.5 TOF Measurement Interval
      7. 8.4.7 Averaging and Channel Selection
      8. 8.4.8 Error Reporting
    5. 8.5 Programming
      1. 8.5.1 Serial Peripheral Interface (SPI)
        1. 8.5.1.1 Chip Select Bar (CSB)
        2. 8.5.1.2 Serial Clock (SCLK)
        3. 8.5.1.3 Serial Data Input (SDI)
        4. 8.5.1.4 Serial Data Output (SDO)
    6. 8.6 Register Maps
  9. 9 Application and Implementation
    1. 9.1 Application Information
    2. 9.2 Typical Applications
      1. 9.2.1 Level and Fluid Identification Measurements
        1. 9.2.1.1 Design Requirements
        2. 9.2.1.2 Detailed Design Procedure
          1. 9.2.1.2.1 Level Measurements
          2. 9.2.1.2.2 Fluid Identification
        3. 9.2.1.3 Application Curves
      2. 9.2.2 Water Flow Metering
        1. 9.2.2.1 Design Requirements
        2. 9.2.2.2 Detailed Design Procedure
          1. 9.2.2.2.1 Regulations and Accuracy
          2. 9.2.2.2.2 Transit-Time in Ultrasonic Flow Meters
          3. 9.2.2.2.3 ΔTOF Accuracy Requirement Calculation
          4. 9.2.2.2.4 Operation
        3. 9.2.2.3 Application Curves
    3. 9.3 Power Supply Recommendations
    4. 9.4 Layout
      1. 9.4.1 Layout Guidelines
      2. 9.4.2 Layout Example
  10. 10Device and Documentation Support
    1. 10.1 Device Support
      1. 10.1.1 Development Support
    2. 10.2 Receiving Notification of Documentation Updates
    3. 10.3 Support Resources
    4. 10.4 Trademarks
    5. 10.5 Electrostatic Discharge Caution
    6. 10.6 Glossary
  11. 11Mechanical, Packaging, and Orderable Information

9.2.1.3 Application Curves

The data used in the following level and fluid identification graphs was collected using ultrasonic test cells. The test cells are acrylic plastic containers with width of 2.54 cm and ultrasonic transducers attached to the outside using cyanoacrylate glue. The transducers in this experiment are STEMiNC 1MHz piezo electric ceramic discs (SMD10T2R111). Equivalent transducers with the following characteristics could be used:

  • Piezo material: SM111
  • Dimensions: 10mm diameter x 2mm thickness
  • Resonant frequency: 1050 kHz (thickness mode)

GUID-CADC8BAB-FF99-4981-A1F1-3297A545DE7E-low.gif
FLUID HEIGHT IN TANK TIME-OF-FLIGHT (µs)
Full (10 cm) 145
Full – 1 (9 cm) 131
Full – 2 (8 cm) 118
3 cm 50
2 cm 35
Figure 9-3 Time-of-Flight for Fluid Height in Tank
GUID-A5314B61-5986-4B78-9921-41EC6346975A-low.gif
FLUID SPEED OF SOUND (m/s)
Distilled water 1481.87
Tap water 1483.13
Figure 9-5 Speed of Sound in Distilled Water and Tap Water
GUID-FC9B77E6-FF0E-4A41-8065-3A73281389C0-low.gif
FLUID SPEED OF SOUND (m/s)
Distilled water 1481.87
Tap water 1483.13
DEF 10.0% 1530.49
DEF 20.0% 1576.42
DEF 30.0% 1620.00
DEF 31.5% 1627.37
DEF 32.0% 1629.15
DEF 32.5% 1630.00
Figure 9-4 Speed of Sound for Various Fluids and Diesel Exhaust Fluid (DEF) Concentration
GUID-207BFC8B-EFC4-468A-AD76-719C36A33E5A-low.gif
FLUID SPEED OF SOUND (m/s)
DEF 30.0% 1620.00
DEF 31.5% 1627.37
DEF 32.0% 1629.15
DEF 32.5% 1630.00
Figure 9-6 Speed of Sound of Various Diesel Exhaust Fluid (DEF) Concentrations