Design of multiple power domains based on ground separation technique for low-noise and small-size module

This paper presents the design of multiple power domains based on filters connecting the separated grounds for a low-noise and small-area module. The sensor module system was composed with analog ICs, digital ICs, and a network process on a PCB of 30 mm × 120 mm and eight layers. Powers of the module consisted of 5V, -5V, 2.5V, -2.5V, and 3.3V by DC-DC ICs and LDO drown from input voltage of 60V. The multiple power domains require ground connection because of common DC ground. For the prevention of high-voltage DC-DC noise, we proposed the ground-isolated technique, connecting grounds with a series of ground filters instead of conventional methods, i.e., a parallel connection with filters between power domains or a common module ground between all power domains. Also, multiple power planes and via stitching are used for low impedance and EMI reduction. The transient simulation shows the clear improvement of transferred noises by about -17 dB reduction, and the measurement results showed an 18% noise voltage reduction compared with common ground techniques.