A power amplifier circuit includes a first amplifier transistor and a bias circuit. The first amplifier transistor amplifies a first signal and outputs a second signal. The bias circuit supplies a bias voltage or a bias current to the first amplifier transistor. The first amplifier transistor includes plural unit transistors disposed in a substantially rectangular region. The bias circuit includes first and second bias transistors and first and second voltage supply circuits. The first and second bias transistors respectively supply first and second bias voltages or first and second bias currents to the bases of unit transistors of first and second groups. The first and second voltage supply circuits respectively supply first and second voltages to the bases of the first and second bias transistors. The first and second voltages are decreased in accordance with a temperature increase. The second voltage supply circuit is disposed within the substantially rectangular region.

A power amplifier circuit includes a first amplifier transistor and a bias circuit. The first amplifier transistor amplifies a first signal and outputs a second signal. The bias circuit supplies a bias voltage or a bias current to the first amplifier transistor. The first amplifier transistor includes plural unit transistors disposed in a substantially rectangular region. The bias circuit includes first and second bias transistors and first and second voltage supply circuits. The first and second bias transistors respectively supply first and second bias voltages or first and second bias currents to the bases of unit transistors of first and second groups. The first and second voltage supply circuits respectively supply first and second voltages to the bases of the first and second bias transistors. The first and second voltages are decreased in accordance with a temperature increase. The second voltage supply circuit is disposed within the substantially rectangular region.

A system may include a plurality of playback paths comprising an open-loop playback path configured to drive an output load and a closed-loop playback path. The closed-loop playback path may include an outer feedback loop comprising one or more integrators, a quantizer, and an output driver for driving the output load, the outer feedback loop having an outer loop feedback gain and an inner feedback loop comprising the one or more integrators and the quantizer and excluding the output driver, wherein the inner feedback loop has a variable inner loop feedback gain which is adjustable to match the outer loop feedback gain.

A system may include a plurality of playback paths comprising an open-loop playback path configured to drive an output load and a closed-loop playback path. The closed-loop playback path may include an outer feedback loop comprising one or more integrators, a quantizer, and an output driver for driving the output load, the outer feedback loop having an outer loop feedback gain and an inner feedback loop comprising the one or more integrators and the quantizer and excluding the output driver, wherein the inner feedback loop has a variable inner loop feedback gain which is adjustable to match the outer loop feedback gain.

A packaged module for use in a wireless communication device has a substrate supporting a crystal assembly and a first die that implements at least a portion of a radio frequency baseband subsystem. The crystal assembly, positioned between the first die and the substrate, includes a crystal, an input terminal configured to receive a first signal, an output terminal configured to output a second signal, a conductive pillar, and an enclosure configured to enclose the crystal, where the conductive pillar is formed at least partially within a side of the enclosure and extends from a top surface to a bottom surface of the enclosure. The conductive pillar conducts a third signal distinct from the first and second signals.

A packaged module for use in a wireless communication device has a substrate supporting a crystal assembly and a first die that implements at least a portion of a radio frequency baseband subsystem. The crystal assembly, positioned between the first die and the substrate, includes a crystal, an input terminal configured to receive a first signal, an output terminal configured to output a second signal, a conductive pillar, and an enclosure configured to enclose the crystal, where the conductive pillar is formed at least partially within a side of the enclosure and extends from a top surface to a bottom surface of the enclosure. The conductive pillar conducts a third signal distinct from the first and second signals.

A power amplifier module includes a combining circuit including a combiner. The combining circuit further includes a first inductor connected in series between an output terminal of a first amplifier and the combiner, a second inductor connected in series between an output terminal of a second amplifier and the combiner, and a second capacitor having an end connected to the combiner and another end grounded. A phase of a third signal from the output terminal of the first amplifier to the second amplifier through the combiner is delayed by about 45 degrees in the first inductor and the second capacitor, and is delayed by about 45 degrees in the second inductor and the second capacitor. A phase of the third signal from the output terminal of the first amplifier to the second amplifier through the first capacitor is advanced by about 90 degrees.

A power amplifier module includes a combining circuit including a combiner. The combining circuit further includes a first inductor connected in series between an output terminal of a first amplifier and the combiner, a second inductor connected in series between an output terminal of a second amplifier and the combiner, and a second capacitor having an end connected to the combiner and another end grounded. A phase of a third signal from the output terminal of the first amplifier to the second amplifier through the combiner is delayed by about 45 degrees in the first inductor and the second capacitor, and is delayed by about 45 degrees in the second inductor and the second capacitor. A phase of the third signal from the output terminal of the first amplifier to the second amplifier through the first capacitor is advanced by about 90 degrees.

A chip module, including a radio frequency integrated circuit (RFIC) chip and a package, and a method and system for designing the module. Chip and package design are performed so the RF front end (FE) is split between chip and package. The chip includes an amplifier with a first differential port and the package includes a passive device and matching network with a second differential port connected to the first differential port. The second differential port is power matched to the first differential port using complex power matching based on port voltage reflection coefficients in order to achieve improved performance (i.e., a peak power transfer across a bandwidth as opposed to at only one frequency). The power matching process can result in a chip power requirement reduction that allows for device size scaling. Thus, designing the chip and designing the package is iteratively repeated in a chip-package co-optimization process.

A chip module, including a radio frequency integrated circuit (RFIC) chip and a package, and a method and system for designing the module. Chip and package design are performed so the RF front end (FE) is split between chip and package. The chip includes an amplifier with a first differential port and the package includes a passive device and matching network with a second differential port connected to the first differential port. The second differential port is power matched to the first differential port using complex power matching based on port voltage reflection coefficients in order to achieve improved performance (i.e., a peak power transfer across a bandwidth as opposed to at only one frequency). The power matching process can result in a chip power requirement reduction that allows for device size scaling. Thus, designing the chip and designing the package is iteratively repeated in a chip-package co-optimization process.