The embodiments described herein include amplifiers that are typically used in radio frequency (RF) applications. The amplifiers described herein use a combiner that is implemented inside the device package. Specifically, the amplifiers can be implemented with a combiner that includes a transmission line inside the device package, where the transmission line has a length between first and second ends configured to provide an impedance inverter between the outputs (e.g., drain terminals) of transistors in the amplifier.