Constant-phase attenuator techniques in radio frequency front end (RFFE) amplifiers

A method of operation for an amplifier, the method comprising:

• outputting, by a high gain active path comprising active circuitry, a first signal comprising a first phase;
• receiving, by a low gain passive path comprising passive circuitry, a second signal comprising a second phase,
• wherein a gain of the high gain active path is higher than a gain of the low gain passive path;
• shifting, by a phase-shifting circuitry within the low gain passive path, the second phase of the second signal to a third phase to generate a third signal comprising the third phase;
• and
• outputting, by the low gain passive path, the third signal comprising the third phase, wherein the third phase approximately matches the first phase.

An amplifier having an input and an output and comprising:

• a high gain path coupled between the input and the output and comprising active circuitry;
• and
• a low gain path coupled between the input and the output and comprising phase-shifting circuitry,
• wherein the phase-shifting circuitry is configured to shift a phase of an input signal within the low gain path such that the phase of an output signal at the output of the amplifier from the low gain path approximately matches a phase of the output signal at the output of the amplifier from the high gain path, and wherein a gain of the high gain path is higher than a gain of the low gain path, wherein the phase-shifting circuitry comprises a first inductor coupled to a first end of a capacitor, and a second inductor coupled to a second end of the capacitor.

An amplifier having an input and an output and comprising:

• a high gain path coupled between the input and the output and comprising active circuitry;
• and
• a low gain path coupled between the input and the output and comprising phase-shifting circuitry,
• wherein the phase-shifting circuitry is configured to shift a phase of an input signal within the low gain path such that the phase of an output signal at the output of the amplifier from the low gain path approximately matches a phase of the output signal at the output of the amplifier from the high gain path, and wherein a gain of the high gain path is higher than a gain of the low gain path, wherein the phase-shifting circuitry comprises two inductors coupled together in series, and a shunt capacitor having a first end coupled between the two inductors and a second end coupled to ground.