Radio frequency front end having shared path with common filter

A radio frequency front end system comprising:

• a first transmit amplifier and a first receive amplifier;
• a first switch configured to selectively couple an output node to the first transmit amplifier or to the first receive amplifier;
• a first transmit filter coupled between the first transmit amplifier and the first switch, and a first receive filter coupled between the first receive amplifier and the first switch;
• a common filter coupled between the first switch and the output node, the common filter together with the first transmit filter configured to band-pass a first radio frequency range and together with the first receive filter configured to band-pass a second radio frequency range different than the first radio frequency range;
• and
• a second transmit amplifier, a second receive amplifier, a first filter bank including the first transmit filter and a second transmit filter, and a second filter bank including the first receive filter and a second receive filter.

A radio frequency front end system comprising:

• a first transmit amplifier and a first receive amplifier;
• a first switch configured to selectively couple an output node to the first transmit amplifier or to the first receive amplifier;
• a first transmit filter coupled between the first transmit amplifier and the first switch, and a first receive filter coupled between the first receive amplifier and the first switch;
• a common filter coupled between the first switch and the output node, the common filter together with the first transmit filter configured to band-pass a first radio frequency range and together with the first receive filter configured to band-pass a second radio frequency range different than the first radio frequency range;
• and
• a second transmit amplifier, a second receive amplifier, and a second switch, the first transmit filter including a transmit diplexer, the first receive filter including a receive diplexer, the second switch configured to selectively couple the output node to the second transmit amplifier or to the second receive amplifier.

A mobile device comprising:

• an antenna;
• a front end system coupled to the antenna and including a first transmit amplifier, a first receive amplifier, a first switch configured to selectively couple an output node to the first transmit amplifier or to the first receive amplifier, a first transmit filter coupled between the first transmit amplifier and the first switch, a first receive filter coupled between the first receive amplifier and the first switch, and a common filter coupled between the first switch and the output node, the common filter together with the first transmit filter configured to band-pass a first radio frequency range and together with the first receive filter configured to band-pass a second radio frequency range different than the first radio frequency range;
• and
• a transmit supplemental filter, a receive supplemental filter, and a second switch ganged together with the first switch, and the second switch configured to selectively couple the transmit supplemental filter to the first transmit amplifier during a transmit period and to couple the receive supplemental filter to the first receive amplifier during a receive period.