In this paper we compare analog to,digital conversion (ADC) delay in H
opfield ADC and asymmetrical (lower triangular) neural network-based A
DC due to Avitabile et al. It is shown that, although Hopfield ADC; ha
s extensive feedback, its behavior in asynchronous mode is similar to
that of lower triangular ADC. It is also shown that any constant delay
n-bit feedforward ADC must have an exponential number of neurons.