LM811: Power Supply FAQ

Question:

The power supply on the board will supply the required current for the module, but do I also need to add any decoupling caps close to the supply pins of the module? Or are they already on the module, and all i need to supply is the +3.3V to the module?

Answer:

• The LM811 doesn’t require any additional capacitors as long as the correct voltage is being used.

Question:

I’ve ordered the WIFI/BT combo-module LM811 with IPEX connector. In the datashaeet I found, that the DC power input is 3.3V. Is it possible to connect a 5V USB interface to the module? Are the USB D+ and D- inputs 5V tolerant? 

Answer:

• It should be fine. However we do not recommend it as it is very easy to damage the module with the wrong voltage signals.

Question:

I’m designing the LM811-0461 into a new design.  I’m not intending to use the WO-WLAN, SUSPEND or BT_PCM functionality, I just want to connect power and USB.  I would like advice on how to connect the unused signals. The BT_PCM_IN pin is documented as an input – should I tie this to ground to prevent the input from floating?

Answer;

• All unused pins can be left unconnected. It is not necessary to tie them to ground.