SBOS473L March   2009  – July 2024 TMP112 , TMP112D

PRODUCTION DATA  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Device Comparison
  6. 5 Pin Configuration and Functions
  7. 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 Timing Diagrams
    8. 6.8 Typical Characteristics (TMP112A/B/N)
    9. 6.9 Typical Characteristics (TMP112Dx)
  8. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagrams
    3. 7.3 Feature Description
      1. 7.3.1 Digital Temperature Output
      2. 7.3.2 Serial Interface
        1. 7.3.2.1 Bus Overview
        2. 7.3.2.2 Serial Bus Address
        3. 7.3.2.3 Writing and Reading Operation
        4. 7.3.2.4 Target Mode Operations
          1. 7.3.2.4.1 Target Receiver Mode
          2. 7.3.2.4.2 Target Transmitter Mode
        5. 7.3.2.5 SMBus Alert Function
        6. 7.3.2.6 General Call
        7. 7.3.2.7 High-Speed (Hs) Mode
        8. 7.3.2.8 Timeout Function
        9. 7.3.2.9 Timing Diagrams
          1. 7.3.2.9.1 Two-Wire Timing Diagrams
    4. 7.4 Device Functional Modes
      1. 7.4.1 Continuous-Conversion Mode
      2. 7.4.2 Extended Mode (EM)
      3. 7.4.3 One-Shot/Conversion Ready Mode (OS)
      4. 7.4.4 Thermostat Mode (TM)
        1. 7.4.4.1 Comparator Mode (TM = 0)
        2. 7.4.4.2 Interrupt Mode (TM = 1)
    5. 7.5 Programming
      1. 7.5.1 Pointer Register
      2. 7.5.2 Temperature Register
      3. 7.5.3 Configuration Register
        1. 7.5.3.1 Shutdown Mode (SD)
        2. 7.5.3.2 Thermostat Mode (TM)
        3. 7.5.3.3 Polarity (POL)
        4. 7.5.3.4 Fault Queue (F1/F0)
        5. 7.5.3.5 Converter Resolution (R1 and R0)
        6. 7.5.3.6 One-Shot (OS)
        7. 7.5.3.7 Extended Mode (EM)
        8. 7.5.3.8 Alert (AL)
      4. 7.5.4 High- and Low-Limit Register
  9. 8 Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Application
      1. 8.2.1 Design Requirements
      2. 8.2.2 Detailed Design Procedure
      3. 8.2.3 Application Curve
      4. 8.2.4 Power Supply Recommendations
    3. 8.3 Layout
      1. 8.3.1 Layout Guidelines
      2. 8.3.2 Layout Example
  10. 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
  11. 10Revision History
  12. 11Mechanical, Packaging, and Orderable Information
    1. 11.1 Tape and Reel Information

7.3.1 Digital Temperature Output

The digital output from each temperature measurement conversion is stored in the read-only temperature register. The temperature register of the TMP112 family is configured as a 12-bit read-only register (setting the EM bit to 0 in the configuration register; see Section 7.5.3.7), or as a 13-bit read-only register (setting the EM bit to 1 in the configuration register) that stores the output of the most recent conversion. Two bytes must be read to obtain data and are listed in Table 7-8 and Table 7-9. Byte 1 is the most significant byte (MSB), followed by byte 2, the least significant byte (LSB). The first 12 bits (13 bits in extended mode) are used to indicate temperature. The least significant byte does not have to be read if that information is not needed. The data format for temperature is listed in Table 7-2 and Table 7-3. One LSB equals 0.0625°C. Negative numbers are represented in binary twos complement format. Following power up or reset, the temperature register reads 0°C until the first conversion is complete. Bit D0 of byte 2 indicates normal mode (EM bit equals 0) or extended mode (EM bit equals 1), and can be used to distinguish between the two temperature register data formats. The unused bits in the temperature register always read 0.

Table 7-2 12-Bit Temperature Data Format
TEMPERATURE (°C) DIGITAL OUTPUT (BINARY) HEX
128 0111 1111 1111 7FF
127.9375 0111 1111 1111 7FF
100 0110 0100 0000 640
80 0101 0000 0000 500
75 0100 1011 0000 4B0
50 0011 0010 0000 320
25 0001 1001 0000 190
0.25 0000 0000 0100 004
0.0625 0000 0000 0001 001
0 0000 0000 0000 000
-0.0625 1111 1111 1111 FFF
–0.25 1111 1111 1100 FFC
–25 1110 0111 0000 E70
–55 1100 1001 0000 C90

Table 7-2 does not list all temperatures. Use the following rules to obtain the digital data format for a given temperature or the temperature for a given digital data format.

To convert positive temperatures to a digital data format:

  1. Divide the temperature by the resolution
  2. Convert the result to binary code with a 12-bit, left-justified format, and MSB = 0 to denote a positive sign.

    Example: (50°C) / (0.0625°C / LSB) = 800 = 320h = 0011 0010 0000

To convert a positive digital data format to temperature:

  1. Convert the 12-bit, left-justified binary temperature result, with the MSB = 0 to denote a positive sign, to a decimal number.
  2. Multiply the decimal number by the resolution to obtain the positive temperature.

    Example: 0011 0010 0000 = 320h = 800 × (0.0625°C / LSB) = 50°C

To convert negative temperatures to a digital data format:

  1. Divide the absolute value of the temperature by the resolution, and convert the result to binary code with a 12-bit, left-justified format.
  2. Generate the twos complement of the result by complementing the binary number and adding one. Denote a negative number with MSB = 1.

    Example: (|–25°C|) / (0.0625°C / LSB) = 400 = 190h = 0001 1001 0000

    Two's complement format: 1110 0110 1111 + 1 = 1110 0111 0000

To convert a negative digital data format to temperature:

  1. Generate the twos compliment of the 12-bit, left-justified binary number of the temperature result (with MSB = 1, denoting negative temperature result) by complementing the binary number and adding one. This represents the binary number of the absolute value of the temperature.
  2. Convert to decimal number and multiply by the resolution to get the absolute temperature, then multiply by –1 for the negative sign.

    Example: 1110 0111 0000 has twos compliment of 0001 1001 0000 = 0001 1000 1111 + 1

    Convert to temperature: 0001 1001 0000 = 190h = 400; 400 × (0.0625°C / LSB) = 25°C = (|–25°C|); (|–25°C|) × (–1) = –25°C

Table 7-3 13-Bit Temperature Data Format
TEMPERATURE (°C) DIGITAL OUTPUT (BINARY) HEX
150 0 1001 0110 0000 0960
128 0 1000 0000 0000 0800
127.9375 0 0111 1111 1111 07FF
100 0 0110 0100 0000 0640
80 0 0101 0000 0000 0500
75 0 0100 1011 0000 04B0
50 0 0011 0010 0000 0320
25 0 0001 1001 0000 0190
0.25 0 0000 0000 0100 0004
0.0625 0 0000 0000 0001 0001
0 0 0000 0000 0000 0000
-0.0625 1 1111 1111 1111 1FFF
–0.25 1 1111 1111 1100 1FFC
–25 1 1110 0111 0000 1E70
–55 1 1100 1001 0000 1C90