An active quenching circuit in 0.35 μm bipolar complementary metal oxide semiconductor (BiCMOS) technology with a high quenching slew rate is introduced. Quenching transients of an integrated single-photon avalanche diode (SPAD) measured by means of an integrated mini-pad are shown. An NPN transistor as quenching switch enables an active quenching time of 350 ps from an excess bias voltage of 6.6 V and a quenching slew rate of 15 V/ns. Active resetting of the SPAD can be achieved in 550 ps. The power consumption of the BiCMOS quenching circuit is 8.6 mW at 40 Mcounts/s and 3 mW in the idle state.