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

10.2.1.2 Detailed Design Procedure

To reduce the wire count, the bus powered mode for the TMP1826 is the primary mode of operation. The VDD pin of the device must be connected to GND and the SDQ pin of the device must be connected to the host GPIO with a pullup resistor.

To calculate the pullup resistor range, substitute the value for VPUR, VOL(MAX), VIH(MIN) and IPU(MIN) in Equation 2 as the VPUR > 2.0 V.

Equation 3. 5.0   –   0.4 4   ×   10 – 3   < R P U R < 5.0   –   4.0 300 × 10 – 6
Equation 4. 1.15   k Ω   < R P U R < 3.33   k Ω

The actual value of the pullup resistor can then be adjusted based on the speed of communication and bus or cable parasitic capacitance.

When the VDD is activated, the TMP1826 draws current through the pullup resistor to charge its internal capacitors. When the internal capacitor is charged to the pullup voltage, the host can start communication. The bus idle state is high, which is maintained by the pullup resistor, when the host puts its GPIO in high impedance state.

The TMP1826 uses the stored charge to operate when the SDQ pin is low and measures the low period to decode bus reset, logic high and logic low sent by the host. Similarly, when the host reads data from the TMP1826, it changes the state of the bus from high to low and releases the bus. Depending on whether the device has to send a logic low or logic high, the device shall either hold the bus low or release the bus immediately.