68HC708KL8 Datasheet, PDF (27/246 Pages) Freescale Semiconductor, Inc – Microcontrollers

General Description
1.5.1 Power Supply Pins (V_DDREG, V_SSREG, V_DD1, V_SS1, V_DD2, and V_SS2)
V_DDREG and V_SSREG are the power supply and ground pins used by the
on-board regulator. In regulator bypass, these become the supply pins
for the USB transceiver.
V_DD1, V_SS1, V_DD2, and V_SS2 are the power supply and ground pins. The
MCU operates from a single power supply.
Fast signal transitions on MCU pins 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 as Figure 1-3
shows. Place the bypass capacitors as close to the MCU power pins as
possible. Use high-frequency-response ceramic capacitors for C_BYPASS.
C_BULK are optional bulk current bypass capacitors for use in applications
that require the port pins to source high current levels.
MCU
V_DDREG, V_DD1, V_DD2
V_SSREG,V_SS1, V_SS2
C_Bypass
0.1 µF
+
C_Bulk
V_DD
NOTE: Component values shown represent typical applications.
Figure 1-3. Power Supply Bypassing
MC68HC708KL8 — Rev. 2.1
Freescale Semiconductor
General Description
General Release Specification
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