Data isolators are described. The data isolators include a differential receiver having cross-coupled single-ended amplifiers. The single-ended amplifiers may be referenced to a time-varying reference potential. The cross-coupling of the single-ended amplifiers may provide high speed, low power consumption operation of the data isolator.

A power amplifier module includes a first transistor that amplifies and outputs a signal, a second transistor that supplies a bias current to a base of the first transistor, and a ballast resistor circuit that is disposed between the base and an emitter of the second transistor and that includes first and second resistive elements and a switching element. The first resistive element is arranged in series on a line connecting the base and the emitter. The first and second resistive elements are series-connected or parallel-connected. When the second resistive element is series-connected to the first transistor, the switching element is parallel-connected to the second resistive element. When the second resistive element is parallel-connected to the first transistor, the switching element is series-connected to the second resistive element. The switching element is switched on/off based on a collector current of the second transistor.

An apparatus includes a transformer including a first inductor, a second inductor, and a third inductor. The apparatus also includes a power amplifier having an output coupled to the first inductor, a low-noise amplifier having an input coupled to a first terminal of the third inductor, and a fourth inductor having a first terminal and a second terminal, wherein the second terminal of the fourth inductor is coupled to a second terminal of the third inductor. The apparatus also includes a switch coupled between the first terminal of the third inductor and the first terminal of the fourth inductor.

Disclosed is a filter bank die that includes a first acoustic wave (AW) filter having a first antenna terminal coupled to the antenna port terminal and a first filter terminal, wherein the first AW filter is configured to have a filter skirt with a slope that spans at least a 100 MHz gap between adjacent passbands, and a second AW filter having a second filter terminal, and a second antenna terminal coupled to the first antenna terminal to effectively diplex signals that pass through the first AW filter and the second AW filter.

Disclosed is a filter bank module having a substrate, an antenna port terminal, and a filter bank die. The filter bank die is fixed to the substrate and includes a first acoustic wave (AW) filter having a first antenna terminal coupled to the antenna port terminal and a first filter terminal, wherein the first AW filter is configured to pass a first passband and attenuate frequencies outside the first passband, and a second AW filter having a second filter terminal, and a second antenna terminal coupled to the first antenna terminal to effectively diplex signals that pass through the first AW filter and the second AW filter, wherein the second AW filter is configured to pass a second passband that is spaced from the first passband to minimize interference between first bandpass and the second bandpass while attenuating frequencies outside the second passband.

Disclosed is a filter bank die having a first acoustic wave (AW) filter having a first antenna terminal and a first filter terminal, and a second AW filter having a second filter terminal, and a second antenna terminal coupled to the first antenna terminal to effectively diplex signals that pass through the first AW filter and the second AW filter.

An envelope tracking (ET) integrated circuit (ETIC) operable with multiple types of power amplifiers is provided. The ETIC is configured to provide one or more ET voltages to a power amplifier(s) for amplifying a radio frequency (RF) signal. In embodiments disclosed herein, the ETIC can be configured to generate the ET voltages at same or different voltage levels based on specific types of the power amplifier(s), such as multi-stage power amplifier and Doherty power amplifier, and for a wider modulation bandwidth of the RF signal. As such, the ETIC can be flexibly adapted to enable a variety of power management scenarios and/or topologies.

A multiplexer includes a transmission filter and a reception filter connected to a common terminal, a first inductor connected to the common terminal, and a multilayer substrate on which the transmission filter and the reception filter are mounted and which includes dielectric layers. The transmission filter includes a parallel-arm resonator connected to a path between the common terminal and a transmission terminal and a parallel-arm terminal, and a second inductor connected to the parallel-arm terminal and ground. The first inductor includes a first coil pattern on a first dielectric layer and a second coil pattern on a second dielectric layer. The second inductor includes a third coil pattern on the first dielectric layer and that is magnetically coupled to the first coil pattern. The inductance value of the second coil pattern is greater than that of the first coil pattern.

A radio frequency module includes: a module board including a first principal surface and a second principal surface on opposite sides; a transmission input terminal; a transmission power amplifier that amplifies a transmission signal input from the transmission input terminal; a switch that switches between connecting and disconnecting the transmission input terminal and the transmission power amplifier, and a control circuit that controls the transmission power amplifier using digital control signals. The switch is disposed on the first principal surface, and the control circuit is disposed on the second principal surface.

There is provided a monolithic microwave integrated circuit, MMIC, front-end module (100) comprising: a gallium nitride structure (110) supported by a silicon substrate (120); a silicon-based transmit/receive switch (130) having a transmit mode and a receive mode; a transmit amplifier (112) configured to amplify an outgoing signal to be transmitted by said MMIC front-end module, wherein said transmit amplifier is electrically connected (132) to said transmit/receive switch, wherein said transmit amplifier comprises a gallium nitride high-electron-mobility transistor, HEMT, (114) formed in said gallium nitride structure; and a receive amplifier (113) configured to amplify an incoming signal received by said MMIC front-end module, wherein said receive amplifier is electrically connected (133) to said transmit/receive switch, wherein said receive amplifier comprises a gallium nitride HEMT (115) formed in said gallium nitride structure.