  Analog neuromorphic hardware promises fast brain emulation on the one hand
and an efficient implementation of novel, brain-inspired computing paradigms on
the other. Bridging this spectrum requires flexibly configurable circuits with
reliable and reproducible dynamics fostered by an accurate implementation of
the targeted neuron and synapse models. This manuscript presents the analog
neuron circuits of the mixed-signal accelerated neuromorphic system
BrainScaleS-2. They are capable of flexibly and accurately emulating the
adaptive exponential leaky integrate-and-fire model equations in combination
with both current- and conductance-based synapses, as demonstrated by precisely
replicating a wide range of complex neuronal dynamics and firing patterns.
