Analog-Digital Co-Design Methodology is a unified design approach that simultaneously optimizes mixed-signal circuit partitioning, interface specifications, and system-level performance — Traditional sequential analog-then-digital design often suboptimizes interfaces and miss opportunities for architecture-level improvements. Architecture Exploration evaluates different analog-digital boundaries considering noise requirements, power consumption, area utilization, and design complexity at each interface. Partition Strategies analyze data flow paths identifying optimal points where analog signals transition to digital domain, considering ADC requirements, signal conditioning needs, and downstream digital processing. Interface Specification defines resolution, sample rate, noise performance, and linearity requirements for ADC/DAC interfaces, ensuring specifications precisely meet system needs without over-specification. Noise Budget Analysis allocates total system noise across analog frontend, ADC quantization, digital processing, and DAC output stages, optimizing each component contribution. Power Management coordinates analog circuit power consumption with digital switching activity, implementing power gating strategies, and managing ground bounce and supply noise. Timing Closure ensures synchronization between analog sampled-data circuits and digital clock domains, managing clock jitter impacts on ADC performance, and coordinating pipeline stages. Design Verification combines analog circuit simulation with digital behavioral models, validates noise and linearity through Monte Carlo analysis, and verifies cross-domain interactions. Analog-Digital Co-Design Methodology delivers optimized mixed-signal systems through integrated design philosophy.