Recommended Power Supply Circuit - Cypress FR81S CY91F52 Series Recommendation For Hardware Setup

3.6

Recommended Power Supply Circuit

To meet EMC requirements for the target board, a noiseless supply is necessary. Therefore, the supply should be
filtered as shown in Figure 10. Switched IO pins like stepper motor controller or external bus interface can generate
spikes on the supplies. These are difficult to filter using capacitors only. A series inductor (ferrite, e.g. WE742792022)
is therefore recommended, as shown.
5V
L
10uF 10uF
GND GND
5V
L
10uF 10uF
GND GND
*R2 (e.g. 10R) : Optional
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Figure 10. Principal Supply circuit
*C (e.g. 1nF) : Optional
Document No. 002-09375 Rev. *B
Recommendation for Hardware Setup 32-Bit FR81S Family
MCU
Close to
MCU pins
Vcc
100nF C*
X7R
GND GND
Vcc
100nF C*
X7R
GND GND
AVcc
100nF C*
X7R
GND GND
AVRH
100nF
C*
X7R
GND GND
AVSS
VSS
GND
12