MPC564EVB Freescale Semiconductor, MPC564EVB Datasheet - Page 611

• Manufacturer Part Number: MPC564EVB
• Description: KIT EVAL FOR MPC561/562/563/564
• Manufacturer: Freescale Semiconductor
• Type: Microcontrollerr

Specifications of MPC564EVB

• Contents: Module Board, Installation Guide, Power Supply, Cable, Software and more
• Processor To Be Evaluated: MPC56x
• Data Bus Width: 32 bit
• Interface Type: RS-232, Ethernet
• For Use With/related Products: MPC561, 562, 563, 564
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

Another approach is to star-point the different grounds near the analog ground signal on the
microcontroller by using small traces for connecting the non-analog grounds to the analog ground. The
small traces are meant only to accommodate DC differences, not AC transients.
Other suggestions for PCB layout in which the QADC64E is employed include:
14.6.4
V
reference inputs from the power supply signals allows for additional external filtering, which increases
reference voltage precision and stability, and subsequently contributes to a higher degree of conversion
accuracy.
Freescale Semiconductor
RH
•
•
•
•
•
and V
Analog ground must be low impedance to all analog ground points in the circuit.
Bypass capacitors should be as close to the power signals as possible.
The analog ground should be isolated from the digital ground. This can be done by cutting a
separate ground plane for the analog ground.
Non-minimum traces should be utilized for connecting bypass capacitors and filters to their
corresponding ground/power points.
Distance for trace runs should be minimized where possible.
PCB
RL
Analog Reference Signals
are the dedicated input signals for the high and low reference voltages. Separating the
This star-point scheme still requires adequate grounding for digital and
analog subsystems in addition to the star-point ground.
+5V
Figure 14-49. Star-Ground at the Point of Power Supply Origin
Analog Power Supply
AGND
QADC64E
MPC561/MPC563 Reference Manual, Rev. 1.2
+5V
VDD
VSS
NOTE
PGND
Digital Power
QADC64E Enhanced Mode Operation
Supply
+5V
14-69