A packaged RF amplifier device includes input and output leads and a transistor die. The transistor die includes a transistor with a drain-source capacitance below 0.1 picofarads per watt. The device also includes a conductive connection between the transistor output terminal and the output lead, and a baseband termination circuit between the transistor output terminal and a ground reference node. The baseband termination circuit presents a low impedance to signal energy at envelope frequencies and a high impedance to signal energy at RF frequencies. The baseband termination circuit includes an inductive element, a resistor, and a capacitor connected in series between the transistor output terminal and the ground reference node. Except for a minimal impedance transformation associated with the conductive connection, the device is unmatched between the transistor output terminal and the output lead by being devoid of impedance matching circuitry between the transistor output terminal and the output lead.