MPC564CZP40 Freescale Semiconductor, MPC564CZP40 Datasheet - Page 534

• Manufacturer Part Number: MPC564CZP40
• Description: IC MPU 32BIT W/CODE COMP 388PBGA
• Manufacturer: Freescale Semiconductor
• Series: MPC5xxr

Specifications of MPC564CZP40

• Core Processor: PowerPC
• Core Size: 32-Bit
• Speed: 40MHz
• Connectivity: CAN, EBI/EMI, SCI, SPI, UART/USART
• Peripherals: POR, PWM, WDT
• Number Of I /o: 56
• Program Memory Size: 512KB (512K x 8)
• Program Memory Type: FLASH
• Ram Size: 32K x 8
• Voltage - Supply (vcc/vdd): 2.5 V ~ 2.7 V
• Data Converters: A/D 32x10b
• Oscillator Type: External
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 388-BGA
• Processor Series: MPC5xx
• Core: PowerPC
• Data Bus Width: 32 bit
• Data Ram Size: 32 KB
• Interface Type: CAN, JTAG, QSPI, SCI, SPI, UART
• Maximum Clock Frequency: 40 MHz
• Number Of Programmable I/os: 56
• Number Of Timers: 2
• Operating Supply Voltage: 0 V to 5 V
• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• Minimum Operating Temperature: - 40 C
• On-chip Adc: 2 (10 bit, 32 Channel)
• For Use With: MPC564EVB - KIT EVAL FOR MPC561/562/563/564
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Eeprom Size: -
• Lead Free Status / Rohs Status: No

QADC64E Legacy Mode Operation
The problem of how and when to combine digital and analog grounds arises from the large transients
which the digital ground must handle. If the digital ground is not able to handle the large transients, the
current from the large transients can return to ground through the analog ground. It is the excess current
overflowing into the analog ground which causes performance degradation by developing a differential
voltage between the true analog ground and the microcontroller’s ground signal. The end result is that the
ground observed by the analog circuit is no longer true ground and often ends in skewed results.
Two similar approaches designed to improve or eliminate the problems associated with grounding excess
transient currents involve star-point ground systems. One approach is to star-point the different grounds at
the power supply origin, thus keeping the ground isolated. Refer to
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:
The analog ground should be isolated from the digital ground. This can be done by cutting a separate
ground plane for the analog ground
13-70
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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.
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
This star-point scheme still requires adequate grounding for digital and
analog subsystems in addition to the star-point ground.
MPC561/MPC563 Reference Manual, Rev. 1.2
NOTE
Figure
13-51.
Freescale Semiconductor