Mobile wireless communications device with reduced interfering energy into audio circuit and related methods

A mobile wireless communications device comprising:

• a housing;
• a circuit board carried by the housing and including radio frequency (RF) circuitry and a processor carried by the circuit board and operative with each other;
• a receiver speaker and a microphone carried by the housing;
• audio circuitry carried by the circuit board and operative with the RF circuitry and processor and including a microphone audio switch and a receiver speaker audio switch and audio connection lines carried by the circuit board and interconnecting the processor and microphone audio switch and receiver speaker audio switch and operatively connected to said receiver speaker and microphone;
• a jack carried by the housing;
• jack connection lines carried by said circuit board and operatively connected to said processor and jack;
• a jack filter operative with the jack connection lines and including a resistor divider for imparting a predetermined bias;
• an operational amplifier circuit connected between said jack filter and processor;
• and
• a filter operative with the audio connection lines and operatively connected to at least one of the microphone audio switch or receiver speaker audio switch such that said jack filter and filter reduce conducted and radiated interfering RF energy from coupling to the audio circuitry.

A method for making a mobile wireless communications device, which comprises:

• providing a housing, a circuit board carried by the housing, radio frequency (RF) circuitry and a processor carried by the circuit board and operative with each other, a receiver speaker and a microphone carried by the housing, audio circuitry carried by the circuit board and operative with the RF circuitry and processor and including a microphone audio switch and a receiver speaker audio switch, and audio connection lines formed as planar signal traces on the circuit board and interconnecting the processor and microphone audio switch and receiver speaker audio switch and operatively connected to said receiver speaker and microphone and a jack carried by the housing and jack connection lines carried by the circuit board and operatively connected to said jack and said processor and at least one of the receiver audio switch and microphone audio switch;
• and
• reducing conducted and radiated interfering RF energy from coupling to the audio circuitry by inserting a filter formed as a ferrite inductor directly on the signal traces forming the audio connection lines such that the filter is operatively connected to at least one microphone audio switch or receiver speaker audio switch while also imparting a predetermined bias through a resistor divider to a jack filter operative with the jack connection lines.

A mobile wireless communications device comprising:

• a housing;
• a circuit board carried by the housing and including radio frequency (RF) circuitry and a processor carried by the circuit board and operative with each other;
• a receiver speaker and a microphone carried by the housing;
• audio circuitry carried by the circuit board and operative with the RF circuitry and processor and including a microphone audio switch and a receiver speaker audio switch and audio connection lines carried by the circuit board and interconnecting the processor and audio switches and operatively connected to said receiver speaker and microphone;
• and
• a filter operative with the audio connection lines and operatively connected to at least one of the microphone audio switch or receiver speaker audio switch to reduce conducted and radiated interfering RF energy from coupling into the audio circuitry, wherein said audio circuit further comprises a jack carried by the housing, and jack connection lines carried by said circuit board and operatively connected to said jack, processor and one of said microphone audio switch or receiver speaker audio switch, and further comprising a jack filter operative with the jack connection lines, wherein said jack filter includes a resistor divider for imparting a predetermined bias.