SBOSA45C february   2022  – may 2023 TMP1826

PRODUCTION DATA  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Revision History
  6. 5 Description (cont.)
  7. 6 Device Comparison
  8. 7 Pin Configuration and Functions
  9. 8 Specifications
    1. 8.1 Absolute Maximum Ratings
    2. 8.2 ESD Ratings
    3. 8.3 Recommended Operating Conditions
    4. 8.4 Thermal Information
    5. 8.5 Electrical Characteristics
    6. 8.6 1-Wire Interface Timing
    7. 8.7 EEPROM Characteristics
    8. 8.8 Timing Diagrams
    9. 8.9 Typical Characteristics
  10. 9 Detailed Description
    1. 9.1 Overview
    2. 9.2 Functional Block Diagram
    3. 9.3 Feature Description
      1. 9.3.1  Power Up
      2. 9.3.2  Power Mode Switch
      3. 9.3.3  Bus Pullup Resistor
      4. 9.3.4  Temperature Results
      5. 9.3.5  Temperature Offset
      6. 9.3.6  Temperature Alert
      7. 9.3.7  Standard Device Address
        1. 9.3.7.1 Unique 64-Bit Device Address and ID
      8. 9.3.8  Flexible Device Address
        1. 9.3.8.1 Non-Volatile Short Address
        2. 9.3.8.2 IO Hardware Address
        3. 9.3.8.3 Resistor Address
        4. 9.3.8.4 Combined IO and Resistor Address
      9. 9.3.9  CRC Generation
      10. 9.3.10 Functional Register Map
      11. 9.3.11 User Memory Map
      12. 9.3.12 Bit Communication
        1. 9.3.12.1 Host Write, Device Read
        2. 9.3.12.2 Host Read, Device Write
      13. 9.3.13 Bus Speed
      14. 9.3.14 NIST Traceability
    4. 9.4 Device Functional Modes
      1. 9.4.1 Conversion Modes
        1. 9.4.1.1 Basic One-Shot Conversion Mode
        2. 9.4.1.2 Auto Conversion Mode
        3. 9.4.1.3 Stacked Conversion Mode
        4. 9.4.1.4 Continuous Conversion Mode
      2. 9.4.2 Alert Function
        1. 9.4.2.1 Alert Mode
        2. 9.4.2.2 Comparator Mode
      3. 9.4.3 1-Wire Interface Communication
        1. 9.4.3.1 Bus Reset Phase
        2. 9.4.3.2 Address Phase
          1. 9.4.3.2.1 READADDR (33h)
          2. 9.4.3.2.2 MATCHADDR (55h)
          3. 9.4.3.2.3 SEARCHADDR (F0h)
          4. 9.4.3.2.4 ALERTSEARCH (ECh)
          5. 9.4.3.2.5 SKIPADDR (CCh)
          6. 9.4.3.2.6 OVD SKIPADDR (3Ch)
          7. 9.4.3.2.7 OVD MATCHADDR (69h)
          8. 9.4.3.2.8 FLEXADDR (0Fh)
        3. 9.4.3.3 Function Phase
          1. 9.4.3.3.1  CONVERTTEMP (44h)
          2. 9.4.3.3.2  WRITE SCRATCHPAD-1 (4Eh)
          3. 9.4.3.3.3  READ SCRATCHPAD-1 (BEh)
          4. 9.4.3.3.4  COPY SCRATCHPAD-1 (48h)
          5. 9.4.3.3.5  WRITE SCRATCHPAD-2 (0Fh)
          6. 9.4.3.3.6  READ SCRATCHPAD-2 (AAh)
          7. 9.4.3.3.7  COPY SCRATCHPAD-2 (55h)
          8. 9.4.3.3.8  READ EEPROM (F0h)
          9. 9.4.3.3.9  GPIO WRITE (A5h)
          10. 9.4.3.3.10 GPIO READ (F5h)
      4. 9.4.4 NVM Operations
        1. 9.4.4.1 Programming User Data
        2. 9.4.4.2 Register and Memory Protection
          1. 9.4.4.2.1 Scratchpad-1 Register Protection
          2. 9.4.4.2.2 User Memory Protection
    5. 9.5 Programming
      1. 9.5.1 Single Device Temperature Conversion and Read
      2. 9.5.2 Multiple Device Temperature Conversion and Read
      3. 9.5.3 Register Scratchpad-1 Update and Commit
      4. 9.5.4 Single Device EEPROM Programming and Verify
      5. 9.5.5 Single Device EEPROM Page Lock Operation
      6. 9.5.6 Multiple Device IO Read
      7. 9.5.7 Multiple Device IO Write
    6. 9.6 Register Map
      1. 9.6.1  Temperature Result LSB Register (Scratchpad-1 offset = 00h) [reset = 00h]
      2. 9.6.2  Temperature Result MSB Register (Scratchpad-1 offset = 01h) [reset = 00h]
      3. 9.6.3  Status Register (Scratchpad-1 offset = 02h) [reset = 3Ch]
      4. 9.6.4  Device Configuration-1 Register (Scratchpad-1 offset = 04h) [reset = 70h]
      5. 9.6.5  Device Configuration-2 Register (Scratchpad-1 offset = 05h) [reset = 80h]
      6. 9.6.6  Short Address Register (Scratchpad-1 offset = 06h) [reset = 00h]
      7. 9.6.7  Temperature Alert Low LSB Register (Scratchpad-1 offset = 08h) [reset = 00h]
      8. 9.6.8  Temperature Alert Low MSB Register (Scratchpad-1 offset = 09h) [reset = 00h]
      9. 9.6.9  Temperature Alert High LSB Register (Scratchpad-1 offset = 0Ah) [reset = F0h]
      10. 9.6.10 Temperature Alert High MSB Register (Scratchpad-1 offset = 0Bh) [reset = 07h]
      11. 9.6.11 Temperature Offset LSB Register (Scratchpad-1 offset = 0Ch) [reset = 00h]
      12. 9.6.12 Temperature Offset MSB Register (Scratchpad-1 offset = 0Dh) [reset = 00h]
      13. 9.6.13 IO Read Register [reset = F0h]
      14. 9.6.14 IO Configuration Register [reset = 00h]
  11. 10Application and Implementation
    1. 10.1 Application Information
    2. 10.2 Typical Applications
      1. 10.2.1 Bus Powered Application
        1. 10.2.1.1 Design Requirements
        2. 10.2.1.2 Detailed Design Procedure
      2. 10.2.2 Supply Powered Application
        1. 10.2.2.1 Design Requirements
        2. 10.2.2.2 Detailed Design Procedure
      3. 10.2.3 UART Interface for Communication
        1. 10.2.3.1 Design Requirements
        2. 10.2.3.2 Detailed Design Procedure
    3. 10.3 Power Supply Recommendations
    4. 10.4 Layout
      1. 10.4.1 Layout Guidelines
      2. 10.4.2 Layout Example
  12. 11Device and Documentation Support
    1. 11.1 Documentation Support
      1. 11.1.1 Related Documentation
    2. 11.2 Receiving Notification of Documentation Updates
    3. 11.3 Support Resources
    4. 11.4 Trademarks
    5. 11.5 Electrostatic Discharge Caution
    6. 11.6 Glossary
  13. 12Mechanical, Packaging, and Orderable Information

Package Options

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

10.2.3.2 Detailed Design Procedure

If using GPIO for communication is not possible due to any reason, it is also possible to use UART peripheral that is available on most host controllers to interface with the TMP1826. UART is a push-pull full duplex bus and to interface with TMP1826, it requires a buffer with open-drain driver like the SN74LVC1G07.

The input of the buffer is connected to the UART transmit pin and the output of the buffer is connected to the SDQ pin on the TMP1826. The output of the buffer is also connected to the UART receive pin on the host. As the output is open-drain, it requires a pullup resistor which can be calculated in Equation 2 as VPUR > 2.0 V. Substituting the value for VPUR = 3.3 V, VOL(MAX) = 0.4 V, VIH(MIN) = 2.64 V and IPU(MIN) = 300 µA, the RPUR value selected must be greater than 725 Ω and less than 2.2 kΩ.

In software, the application must adjust its baud rate so that it can send bus reset to the device by sending 00h. The start bit of the UART frame which is always 0, provides the required falling edge for data sent to the TMP1826. When sending a logic high to the device, the UART shall send FFh to the TMP1826 and, when sending a logic low to the device, the UART shall send C0h. As UART is a full duplex bus, the host must flush its receive buffers during a transmit operation.

When receiving data from the TMP1826, the host shall send FFh and the device when transmitting a logic high will detect and release the bus, while when transmitting a logic low will detect and hold the bus low. As a result, the host shall receive a FFh for a logic high and F0h for a logic low depending on the baud rate configured.