13/19

E981.10

ELMOS Semiconductor AG

Data Sheet

QM-No.: 25DS0007E.02 2010-06-16

5.4 receiver

5.5 Wake-up

The receiver reads logic information from the C/Q pin and proceeds it to the control unit. The data bits are filtered

in order to suppress erroneous glitches on the C/Q pin and to increase EMC robustness. The receiver functionality

will not be available in the whole IC supply range due to absolute thresholds. If the transceiver supply voltage falls

below 18V, the system may not be able to guarantee sufficient high levels on the C/Q pin and the receiver will out-

put a constant low level on pin RXD.

In case of an active transmitter the receiver monitors pin C/Q in order to detect wake up events. If the in-

formation read from the C/Q pin changes state, while TXD remains constant, a wake up event is as-

sumed. Alternatively the change to an overcurrent state is evaluated in the same way. The transmitter re-

mains on despite having detected an overload. After Twu the wake up event is signalled at pin WAKE and

the transmitter is turned off. It can be reset with a TXEN=low and activated again with a new TXEN=high.

The figure below shows the functionality of the overcurrent and wake up recognition as well as the resulting be-

havior at the pin ILIM and WAKE UP in detail.