Datasheet

Regulator Power Supply Configuration (VREG)
MC68HC908AP Family Data Sheet, Rev. 4
Freescale Semiconductor 27
V
DDA
and V
SSA
are the power supply and ground pins for the analog circuits of the MCU. These pins
should be decoupled as per the digital power supply pins.
Figure 1-5. Power Supply Bypassing
1.7 Regulator Power Supply Configuration (VREG)
V
REG
is the output from the on-chip regulator. All internal logics, except for the I/O pads, are powered by
V
REG
output. V
REG
requires an external ceramic bypass capacitor of 100 nF as Figure 1-6 shows. Place
the bypass capacitor as close to the V
REG
pin as possible.
Figure 1-6. Regulator Power Supply Bypassing
MCU
V
DD
C2(a)
C1(a)
0.1 µF
V
SS
V
DD
+
NOTE: Component values shown represent typical applications.
V
DD
C2(b)
C1(b)
0.1 µF
V
SSA
V
DDA
+
MCU
V
SS
V
REG
C
VREGBYPASS
100 nF