SBAA565 November   2022 ADC081C021 , ADC081C027 , ADC101C021 , ADC101C027 , ADC121C021 , ADC121C021-Q1 , ADC121C027 , ADC128D818 , ADS1000 , ADS1000-Q1 , ADS1013 , ADS1014 , ADS1015 , ADS1015-Q1 , ADS1100 , ADS1110 , ADS1112 , ADS1113 , ADS1114 , ADS1115 , ADS1115-Q1 , ADS7823 , ADS7827 , ADS7828 , ADS7828-Q1 , ADS7830 , ADS7924 , AFE539A4 , DAC081C081 , DAC081C085 , DAC101C081 , DAC101C081Q , DAC101C085 , DAC121C081 , DAC121C085 , DAC43204 , DAC43401 , DAC43401-Q1 , DAC43608 , DAC43701 , DAC43701-Q1 , DAC53002 , DAC53004 , DAC53202 , DAC53204 , DAC53204W , DAC53401 , DAC53401-Q1 , DAC53608 , DAC53701 , DAC53701-Q1 , DAC5571 , DAC5573 , DAC5574 , DAC5578 , DAC60501 , DAC60502 , DAC63002 , DAC63004 , DAC63202 , DAC63204 , DAC6571 , DAC6573 , DAC6574 , DAC6578 , DAC70501 , DAC70502 , DAC7571 , DAC7573 , DAC7574 , DAC7578 , DAC7678 , DAC80501 , DAC80502 , DAC8571 , DAC8574

 

  1.   Abstract
  2.   Trademarks
  3. 1I2C Overview
    1. 1.1 History
    2. 1.2 I2C Speed Modes
  4. 2I2C Physical Layer
    1. 2.1 Two-Wire Communication
    2. 2.2 Open-Drain Connection
    3. 2.3 Non-Destructive Bus Contention
  5. 3I2C Protocol
    1. 3.1 I2C START and STOP
    2. 3.2 Logical Ones and Zeros
    3. 3.3 I2C Communication Frames
  6. 4I2C Examples
    1. 4.1 DAC80501 Example
      1. 4.1.1 DAC80501 DAC Data Register
      2. 4.1.2 DAC80501 I2C Example Write
    2. 4.2 ADS1115 Example
      1. 4.2.1 ADS1115 Configuration Register
      2. 4.2.2 ADS1115 I2C Example Read
      3. 4.2.3 ADS1115 Conversion Result
  7. 5Reserved Addresses
    1. 5.1 General Call
    2. 5.2 START Byte
    3. 5.3 C-Bus Address, Different Bus Format, Future Purposes
    4. 5.4 HS-Mode Controller Code
    5. 5.5 Device ID
    6. 5.6 10-Bit Target Addressing
      1. 5.6.1 10-Bit Target Addressing Write
      2. 5.6.2 10-Bit Target Addressing Read
  8. 6Advanced Topics
    1. 6.1 Clock Synchronization and Arbitration
    2. 6.2 Clock Stretching
    3. 6.3 Electrical Specifications
    4. 6.4 Voltage Level Translation
      1. 6.4.1 Example 1
      2. 6.4.2 Example 2
      3. 6.4.3 Example 3
      4. 6.4.4 Example 4
    5. 6.5 Pullup Resistor Sizing
      1. 6.5.1 Minimum Pullup Resistance Sizing
      2. 6.5.2 Maximum Pullup Resistance Sizing
  9. 7Protocols Similar to I2C
  10. 8Summary

6.3 Electrical Specifications

The data sheet for every I2C device has electrical specifications that cover the characteristics for the I2C bus. Because I2C is a common protocol, these specifications are matched from device to device. This section discusses the electrical characteristics as shown in the I2C specification.

This application note does not go into detail about each of the specifications, but gives an overview of how these specifications are organized. Data sheets for I2C devices cover specifications on what is needed to operate TI devices.

As an example, Table 6-2 shows electrical characteristics from the ADS1119 digital input and output for the I2C digital lines.

Table 6-2 Electrical Characteristics of the ADS1119 Digital Inputs and Outputs
Parameter Test Conditions Minimum Typical Maximum Unit
VIL Logic input level, low DGND 0.3 DVDD V
VIH Logic input level, high

2.3 V ≤ DVDD < 3.0 V,

SCL, SDA, A0, A1, DRDY

 0.7 DVDD DVDD + 0.5 V

3.0 V ≤ DVDD ≤ 3.0 V,

SCL, SDA, A0, A1, DRDY

 0.7 DVDD 5.5 V
RESET 0.7 DVDD DVDD V
Vhys Hysteresis of Schmitt-trigger inputs Fast-mode, fast-mode plus 0.05 DVDD V
VOL Logic output level, low IOL = 3 mA DGND 0.15 0.4 V
IOL Low-level output current VOL = 0.4 V, standard-mode, fast-mode 3 mA
VOL = 0.4 V, fast-mode plus 20
VOL = 0.6 V, fast-mode 6
Ii Input current DGND + 0.1 V < VDigital Input < DVDD – 0.1 V –10 10 μA
Ci Capacitance Each pin 10 pF

Highlighting some of the parameters, the table gives specifications for low-level and high-level input and output voltages for SCL and SDA. This specifies that each I2C bus line has a voltage range that correctly transmits and receives high and low levels. This table also gives the minimum output current that the device open drains pull down on SCL and SDA. There are also specific characteristics depending on the I2C mode used.

In whatever I2C devices used, these SCL and SDA bus line characteristics are found in their respective data sheets. The data sheets give enough of these characteristics to set up the device correctly. For further information see the I2C specifications.