SLVA704A June   2015  – October 2026 INA209 , INA219 , INA220 , INA220-Q1 , INA223 , INA226 , INA226-Q1 , INA230 , INA231 , INA3221 , INA3221-Q1 , LM8323 , LM8325-1 , LM8327 , LM8328 , LM8330 , LM8333 , LM8335 , OPT3001 , OPT3001-Q1 , OPT3002 , OPT3004 , OPT3006 , OPT3007 , P82B715 , P82B96 , PCA6107 , PCA9306 , PCA9306-Q1 , PCA9515A , PCA9515B , PCA9518 , PCA9534 , PCA9534A , PCA9535 , PCA9536 , PCA9538 , PCA9539 , PCA9543A , PCA9544A , PCA9545A , PCA9546A , PCA9548A , PCA9554 , PCA9554A , PCA9555 , PCA9557 , PCF8574 , PCF8574A , PCF8575 , PCF8575C , TCA4311A , TCA5405 , TCA6408A , TCA6416A , TCA6418E , TCA6424A , TCA6507 , TCA8418 , TCA8418E , TCA8424 , TCA9406 , TCA9509 , TCA9517 , TCA9517A , TCA9534 , TCA9534A , TCA9535 , TCA9538 , TCA9539 , TCA9539-Q1 , TCA9543A , TCA9544A , TCA9545A , TCA9546A , TCA9548A , TCA9554 , TCA9554A , TCA9555 , TCA9617A , TCA9617B , TCA9800 , TCA9801 , TCA9802 , TCA9803

 

  1.   1
  2.   Abstract
  3.   Trademarks
  4. 1Electrical Characteristics
    1. 1.1 Open-Drain for Bidirectional Communication
      1. 1.1.1 Open-Drain Pulling Low
      2. 1.1.2 Open-Drain Releasing Bus
  5. 2I2C Interface
    1. 2.1 General I2C Operation
      1. 2.1.1 START and STOP Conditions
      2. 2.1.2 Repeated START Condition
    2. 2.2 Data Validity and Byte Format
    3. 2.3 Acknowledge (ACK) and Not Acknowledge (NACK)
  6. 3I2C Data
    1. 3.1 Writing to a Target On The I2C Bus
    2. 3.2 Reading From a Target On The I2C Bus
  7. 4Revision History

1.1.2 Open-Drain Releasing Bus

When the target or controller wishes to transmit a logic high, it may only release the bus by turning off the pull-down FET. This leaves the bus floating, and the pull-up resistor will pull the voltage up to the voltage rail, which will be interpreted as a high. Figure 1-3 shows the flow of current through the pull-up resistor, which pulls the bus high.

Releasing the Bus With An Open-Drain InterfaceFigure 1-3 Releasing the Bus With An Open-Drain Interface