For high peak-to-average power ratio (PAPR) signals and varying average power, base station (BS) power amplifiers (PAs) should exhibit a high output back-off (OBO) efficiency. To maintain efficient operation even at low network load, the PAs should also feature a low-power off-state, but turn-on quickly to maintain real-time capability. This paper presents the design of a three-stage Doherty PA (DPA) at 700 to 800 MHz with an off-state energy consumption of 500 μW and a turn-on time of 44 ns. At 750 MHz, it achieves a gain of 10 dB and a power-added-efficiency (PAE) of 62% at 44 dBm output power. The three parallel amplifier paths are tuned for high OBO efficiency and measured PAE remains larger than 49% over 10 dB OBO. Measurements with modulated burst signals show the significant dc-to-RF efficiency increase at low network loads due to the implemented switching capability. By means of digital predistortion (DPD), a low error vector magnitude (EVM) is achieved for 10 MSym/s signals.