An artificial neural network (ANN) accelerator is provided. The ANN accelerator includes digital controlled oscillators (DCOs), digital-to-time converters (DTCs) and a mixed-signal multiply-and-accumulate (MAC) array. Each DCO generates a first analog operand signal based on a first digital data value, and transmits the first analog operand signal along a respective column signal line. Each DTC generates a second analog operand signal based on a second digital data value, and transmits the second analog operand signal along a respective row signal line. The mixed-signal MAC array is coupled to the row and column signal lines, and includes mixed-signal MAC units. Each mixed-signal MAC unit includes an integrated clock gate (ICG) that generates a digital product signal based on the first and second analog operand signals, and a counter circuit that increments or decrements a count value stored in a register based on the digital product signal.