The device only applies the acknowledge condition if all of the following occurs:

• A set RFA bit requests an acknowledge
• The transmitted device address matches with the device address of the device
• Correct reception of 16 bits occurred

In this case, the device turns on the internal ACKN-MOSFET and pulls the MODE/DATA pin low for the time t_ACKN, which is 520 μs maximum. The acknowledge condition is valid after an internal delay time t_valACK. This means the internal ACKN-MOSFET turns on after t_valACK, on detection of the last falling edge of the protocol. The master controller keeps the line low during this time.

The master device can detect the acknowledge condition with its input by releasing the MODE/DATA pin after t_valACK and reading back a 0.

In case of an invalid device address, or not-correctly-received protocol, application of a no-acknowledge condition does not occur; thus, the internal MOSFET does not turn on, and the external pullup resistor pulls the MODE/DATA pin high after t_valACK. One can use the MODE/DATA pin again after the acknowledge condition ends.

In case of a push-pull output stage, TI recommends using a series resistor in the MODE/DATA line to limit the current to 500 μA in case of an accidentally requested acknowledge, to protect the internal ACKN-MOSFET.