How do I design the power integrity for a high speed digital circuit on a mixed signal RF PCB?

Designing the power integrity for a high-speed digital circuit on a mixed-signal RF PCB ensures that the power distribution network (PDN) delivers clean, stable voltage to the digital ICs while minimizing noise coupling to the sensitive RF circuits on the same board. The design addresses: target impedance (the PDN must present an impedance below the target impedance Z_target at all frequencies up to the maximum switching frequency of the digital ICs; Z_target = V_dd × ripple% / I_transient; for a 1V supply with 5% ripple tolerance and 1A transient current: Z_target = 1 × 0.05 / 1 = 50 milliohms), decoupling capacitor strategy (a hierarchy of capacitors provides low impedance across a wide frequency range: bulk capacitors (10-100 uF electrolytic or tantalum) for DC-1 MHz, ceramic capacitors (0.1-10 uF, 0402-0805 size) for 1 MHz-100 MHz, and the power plane capacitance (the PCB power-ground plane pair provides intrinsic capacitance at 100 MHz-1 GHz: C_plane = epsilon × A / d, where A is the plane area and d is the plane spacing)), power plane design (dedicated power and ground planes in the PCB stackup provide the lowest-impedance PDN at high frequencies; the plane pair acts as a distributed capacitor and a low-inductance current return path; for mixed-signal boards: separate analog/RF and digital power planes to prevent digital switching noise from coupling to the RF circuits; connect the planes at a single point or through ferrite beads to provide isolation while sharing a common ground), and isolation techniques (between digital and RF sections: ferrite beads on the digital power supply (provide 10-30 dB of high-frequency noise isolation), separate voltage regulators for digital and RF sections (each regulator provides independent regulation and noise rejection), and physical separation (route digital and RF circuits in different board regions with a clear boundary)).