User's Manual

USER MANUAL 1.34

STM 300 / STM 300C / STM 300U

The figure above shows two examples how the WAKE inputs may be used. When the LRN

button is pressed WAKE1 is pulled to GND and a teach-in telegram is transmitted.

As long as the button is pressed a small current is flowing from UVDD to GND.

WAKE0 is connected to a toggle switch. There is no continuous flow of current in either po-

sition of the switch.

If more digital inputs with WAKE functionality are needed in an application, WAKE0 can be

combined with some of the digital inputs as shown below:

4.4 Using RVDD

If RVDD is used in an application circuit a serial ferrite bead shall be used and wire length

should be as short as possible (<3 cm). The following ferrite beads have been tested:

74279266 (0603), 74279205 (0805) from Würth Elektronik. During radio transmission and

reception only small currents may be drawn (I<100 µA).

Pulsed current drawn from RVDD has to be avoided. If pulsed currents are necessary, suffi-

cient blocking has to be provided.