  This paper describes the design of a differential class-E PA for Bluetooth
applications in 0.18um CMOS technology with load mismatch protection and power
control features. The breakdown induced by load mismatch can be avoided by
attenuating the RF power to the final stage during over voltage conditions.
Power control is realized by means of "open loop" techniques to regulate the
power supply voltage, and a novel controllable bias network with temperature
compensated is proposed, which allows a moderate power control slope (dB/V) to
be achieved. Post-layout Simulation results show that the level of output power
can be controlled in 2dBm steps; especially the output power in every step is
quite insensitive to temperature variations.
