A digital-intensive, low-area, time-based ADC optimized for in-situ neural recording is fabricated in a 65nm test chip and validated with in-vivo data. The intrinsic inversely proportional gain of a beat frequency based quantizer allows recording of sub-millivolt neural signals without any sophisticated amplifiers or filters. A low-area analog-front-end (AFE) is implemented with a standard digital logic inverter transimpedance amplifier and tunable low pass and high pass filters. The test chip achieves 20.9dB SNDR for a 1mVpp input at 416Hz with a bandwidth of 4.2 kHz and consumes 52μW at 0.8V. In-vivo evoked potentials and spontaneous activity were measured directly from a mouse cerebellum without any external components, validating the efficacy of the aggressive tradeoffs. These results are achieved in an area of 0.0094mm 2 /channel, including on-chip AC coupling and filter passives, which makes this an attractive architecture for complete integration in ultra-high channel count neural recording systems.