Cypress FR81S CY91F52 Series Recommendation For Hardware Setup page 11

Usually the noise current should flows thought the soldering pad of decoupling capacitor CB. The following routing and
placement for single-side assembled boards is recommended:
The following routing and placement for multi-layer PCB is recommended. Note that despite the capacitor is placed on
the opposite side as the MCU, this solution is the best for high-density board assembly.
L1 (MCU)
L2 (GND)
L3 (VCC)
L4
www.cypress.com
Figure 8. Power Supply decoupling on single-side assembled boards
Figure 9. Power Supply decoupling on double-side assembled boards
VCC
MCU
VSS
Document No. 002-09375 Rev. *B
Recommendation for Hardware Setup 32-Bit FR81S Family
L4
L3 (VCC)
L2 (GND)
L1 (MCU)
11