This paper presents the design and applications of a novel mixed analog-digital integrated circuit, that computes in real time biologicallyrealistic models of neurons and neural networks. The IC is organized as a programmable array of modules, which can be parameterized and interconnected like the modeled cells. On-chip memory cells dynamically store the programming data. The whole analog simulation system exploiting the circuit is described, and applications examples are reported, to validate different configurations and compare with numerical simulations.