SLASEJ4C April   2017  – February 2023 PGA460

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
    5. 6.5  Internal Supply Regulators Characteristics
    6. 6.6  Transducer Driver Characteristics
    7. 6.7  Transducer Receiver Characteristics
    8. 6.8  Analog to Digital Converter Characteristics
    9. 6.9  Digital Signal Processing Characteristics
    10. 6.10 Temperature Sensor Characteristics
    11. 6.11 High-Voltage I/O Characteristics
    12. 6.12 Digital I/O Characteristics
    13. 6.13 EEPROM Characteristics
    14. 6.14 Timing Requirements
    15. 6.15 Switching Characteristics
    16. 6.16 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  Power-Supply Block
      2. 7.3.2  Burst Generation
        1. 7.3.2.1 Using Center-Tap Transformer
        2. 7.3.2.2 Direct Drive
        3. 7.3.2.3 Other Configurations
      3. 7.3.3  Analog Front-End
      4. 7.3.4  Digital Signal Processing
        1. 7.3.4.1 Ultrasonic Echo—Band-Pass Filter
        2. 7.3.4.2 Ultrasonic Echo–Rectifier, Peak Hold, Low-Pass Filter, and Data Selection
        3. 7.3.4.3 Ultrasonic Echo—Nonlinear Scaling
        4. 7.3.4.4 Ultrasonic Echo—Threshold Data Assignment
        5. 7.3.4.5 Digital Gain
      5. 7.3.5  System Diagnostics
        1. 7.3.5.1 Device Internal Diagnostics
      6. 7.3.6  Interface Description
        1. 7.3.6.1 Time-Command Interface
          1. 7.3.6.1.1 RUN Commands
          2. 7.3.6.1.2 CONFIGURATION/STATUS Command
        2. 7.3.6.2 USART Interface
          1. 7.3.6.2.1 USART Asynchronous Mode
            1. 7.3.6.2.1.1 Sync Field
            2. 7.3.6.2.1.2 Command Field
            3. 7.3.6.2.1.3 Data Fields
            4. 7.3.6.2.1.4 Checksum Field
            5. 7.3.6.2.1.5 PGA460 UART Commands
            6. 7.3.6.2.1.6 UART Operations
              1. 7.3.6.2.1.6.1 No-Response Operation
              2. 7.3.6.2.1.6.2 Response Operation (All Except Register Read)
              3. 7.3.6.2.1.6.3 Response Operation (Register Read)
            7. 7.3.6.2.1.7 Diagnostic Field
            8. 7.3.6.2.1.8 USART Synchronous Mode
          2. 7.3.6.2.2 One-Wire UART Interface
          3. 7.3.6.2.3 Ultrasonic Object Detection Through UART Operations
        3. 7.3.6.3 In-System IO-Pin Interface Selection
      7. 7.3.7  Echo Data Dump
        1. 7.3.7.1 On-Board Memory Data Store
        2. 7.3.7.2 Direct Data Burst Through USART Synchronous Mode
      8. 7.3.8  Low-Power Mode
        1. 7.3.8.1 Time-Command Interface
        2. 7.3.8.2 UART Interface
      9. 7.3.9  Transducer Time and Temperature Decoupling
        1. 7.3.9.1 Time Decoupling
        2. 7.3.9.2 Temperature Decoupling
      10. 7.3.10 Memory CRC Calculation
      11. 7.3.11 Temperature Sensor and Temperature Data-Path
      12. 7.3.12 TEST Pin Functionality
    4. 7.4 Device Functional Modes
    5. 7.5 Programming
      1. 7.5.1 UART and USART Communication Examples
    6. 7.6 Register Maps
      1. 7.6.1 EEPROM Programming
      2. 7.6.2 Register Map Partitioning and Default Values
      3. 7.6.3 REGMAP Registers
  8. 8 Application and Implementation
    1. 8.1 Application Information
      1. 8.1.1 Transducer Types
    2. 8.2 Typical Applications
      1. 8.2.1 Transformer-Driven Method
        1. 8.2.1.1 Design Requirements
        2. 8.2.1.2 Detailed Design Procedure
          1. 8.2.1.2.1 Transducer Driving Voltage
          2. 8.2.1.2.2 Transducer Driving Frequency
          3. 8.2.1.2.3 Transducer Pulse Count
          4. 8.2.1.2.4 Transformer Turns Ratio
          5. 8.2.1.2.5 Transformer Saturation Current and Main Voltage Rating
        3. 8.2.1.3 Application Curves
      2. 8.2.2 Direct-Driven (Transformer-Less) Method
        1. 8.2.2.1 Design Requirements
        2. 8.2.2.2 Detailed Design Procedure
        3. 8.2.2.3 Application Curves
    3. 8.3 Power Supply Recommendations
    4. 8.4 Layout
      1. 8.4.1 Layout Guidelines
      2. 8.4.2 Layout Example
  9. 9 Device and Documentation Support
    1. 9.1 Documentation Support
      1. 9.1.1 Related Documentation
    2. 9.2 Receiving Notification of Documentation Updates
    3. 9.3 Support Resources
    4. 9.4 Trademarks
    5. 9.5 Electrostatic Discharge Caution
    6. 9.6 Glossary
  10. 10Mechanical, Packaging, and Orderable Information

Package Options

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

7.3.11 Temperature Sensor and Temperature Data-Path

The PGA460 device has an on-chip temperature sensor and a dedicated temperature data path for accurate temperature measurement. The output value is provided as an unsigned 8-bit number from –40°C to +125°C. The temperature sensor measurement can be used to adjust the variation of the transducer performance as the ambient temperature changes. The temperature measurement's sample and conversion time requires at least 100 us after the temperature measurement command is issued. Do not send other commands during this time to allow the temperature value to properly update.

The output of the temperature digital data path can be read by using the time-command interface of the UART interface. The value provided is related to the measured temperature as shown in #X250.

Equation 7. GUID-35C0DA79-4312-4C7B-A100-5D6B9932976D-low.gif

where

  • T(VAL) is value read from the device using TCI or UART commands.
  • T is the temperature.
  • TEMP_GAIN and TEMP_OFF are signed values in the limits from –8 to +7.

Because the output value of T(VAL) after the calculation can result in a decimal number, the value is rounded-up to the closest integer value.

#X1446 shows the temperature digital data path, which has a 16-sample averager and a scaling block. The 16-sample averaging block averages 16 temperature measurements arriving at a rate of 1 sample/µs into one result to remove temperature measurement variations. The scaling block is used to adjust the Gain and the offset parameter to better calibrate the temperature sensor. These two parameters are programmed using TEMP_GAIN and TEMP_OFF bits in the TEMP_TRIM EEPROM register.

GUID-03EBFA5F-4590-4DBE-87BC-3FD02C2B621C-low.gifFigure 7-39 Temperature-Sensor Signal Path

Before compensation (TEMP_GAIN bit set to 0, TEMP_OFF bit set to 0), T(VAL) is same the value converted by the ADC. As previously above, the user can compensate for variations in operating conditions (VPWR), board design, and configuration of the device by performing a two-temperature measurement and trim. After compensation, T(VAL) can be converted to an absolute temperature using #X250. As the VPWR is increased, power dissipation increases and the internal die temperature can be different from the ambient temperature. The temperature sensor always indicates the die temperature.

Without calibrating TEMP_GAIN and TEMP_OFF, the ambient temperature can be approximated from the die temperature reading using #T4793009-6

Equation 8. TAmbient (°C) = TDie - [RθJA × (VPWR × IVPWR_RX_ONLY)]

where

  • RθJA (°C/W) is the Junction-to-ambient thermal resistance of 96.1°C/W.
  • VPWR (V) is the input voltage.
  • IVPWR_RX_ONLY (mA) is the supply current from VPWR pin during listen only mode of 12 mA.