Accurate capture and efficient control of neurological disorders such as epileptic seizures that often originate in multiple regions of the brain, requires neural interface microsystems with an ever-increasing need for higher channel counts. Addressing this demand within the limited energy and area of brain-implantable medical devices necessitates a search for new circuit architectures. In the conventional designs [1-5], the channel area is dominated by the bulky coupling capacitors and/or capacitor banks of the in-channel ADC, both unavoidable due to the channel architecture, and unscalable with CMOS technology. Additionally, channel power consumption, typically dominated by the LNA, cannot be reduced lower than a certain limit without sacrificing gain and/or noise performance. In this paper, we present a 64-channel wireless closed-loop neurostimulator with a compact and energy-efficient channel architecture that performs both amplification and digitization in a single ΔΣ-based neural ADC, while removing rail-to-rail input DC offset using a digital feedback loop. The channel area and power consumption depend only on the active components and switching frequency, respectively, making the design both technology- and frequency-scalable.