Technical data

Analog Integrated Circuit Device Data
Freescale Semiconductor 55
908E621
TYPICAL APPLICATIONS
EMC/EMI RECOMMENDATIONS
This paragraph gives some device specific
recommendations to improve EMC/EMI performance.
Further generic design recommendations can be e.g. found
on the Freescale web site www.freescale.com.
VSUP terminals (VSUP[1:8])
Its recommended to place a high quality ceramic
decoupling capacitor close to the VSUP terminals to improve
EMC/EMI behavior.
LIN terminal
For DPI (Direct Power Injection) and ESD (Electrostatic
Discharge) its recommended to place a high quality ceramic
decoupling capacitor near the LIN terminal. An additional
varistor will further increase the immunity against ESD. A
ferrite in the LIN line will suppress some of the noise induced.
Voltage regulator output terminals (VDD and VSS)
Use a high quality ceramic decoupling capacitor to
stabilize the regulated voltage.
MCU digital supply terminals (EVDD and EVSS)
Fast signal transitions on MCU terminals place high, short-
duration current demands on the power supply. To prevent
noise problems, take special care to provide power supply
bypassing at the MCU. It is recommended that a high quality
ceramic decoupling capacitor be placed between these
terminals.
MCU analog supply terminals (VREFH/VDDA and VREFL/
VSSA)
To avoid noise on the analog supply terminals, its
important to take special care on the layout. The MCU digital
and analog supplies should be tied to the same potential via
separate traces and connected to the voltage regulator
output.
Figure 32
and Figure 33 show the recommendations on
schematics and layout level and Table 23 indicates
recommended external components and layout
considerations.
Figure 32. EMC/EMI recommendations
MM908E621
EVDD
VDD
EVSS
VSS
VSUP[1:8]
GND[1:4]
V
SUP
+
VDDA/VREFH
VSSA/VREFL
LINLIN
C1
C2
D1
C3 C4
C5
L1
V1