MPC8315E-RDBA Freescale Semiconductor, MPC8315E-RDBA Datasheet - Page 107

• Manufacturer Part Number: MPC8315E-RDBA
• Description: BOARD MPU 8315 POWERQUICC II
• Manufacturer: Freescale Semiconductor
• Series: PowerQUICC II™ PROr
• Type: MPUr

Specifications of MPC8315E-RDBA

• Contents: Board
• Processor To Be Evaluated: MPC8315E
• Data Bus Width: 32 bit
• Interface Type: Ethernet, I2C, SPI, UART
• Operating Supply Voltage: 1.8 V
• For Use With/related Products: MPC8315E
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

There are a number of ways to reliably provide power to the PLLs, but the recommended solution is to
provide independent filter circuits as illustrated in
independent filters to each PLL the opportunity to cause noise injection from one PLL to the other is
reduced.
This circuit is intended to filter noise in the PLLs resonant frequency range from a 500 kHz to 10 MHz
range. It should be built with surface mount capacitors with minimum Effective Series Inductance (ESL).
Consistent with the recommendations of Dr. Howard Johnson in High Speed Digital Design: A Handbook
of Black Magic (Prentice Hall, 1993), multiple small capacitors of equal value are recommended over a
single large value capacitor.
Each circuit should be placed as close as possible to the specific AV
noise coupled from nearby circuits. It should be possible to route directly from the capacitors to the AV
pin, which is on the periphery of package, without the inductance of vias. Note that the RC filter results in
lower voltage level on AVDD. This does not imply that the DC specification can be relaxed.
Figure 63
26.3
Due to large address and data buses, and high operating frequencies, the device can generate transient
power surges and high frequency noise in its power supply, especially while driving large capacitive loads.
This noise must be prevented from reaching other components in the MPC8315E system, and the
MPC8315E itself requires a clean, tightly regulated source of power. Therefore, it is recommended that
the system designer place at least one decoupling capacitor at each VDD, NVDD, GVDD, and LVDD pins
of the device. These decoupling capacitors should receive their power from separate VDD, NVDD,
GVDD, LVDD, and GND power planes in the PCB, utilizing thick and short traces to minimize
inductance. Capacitors may be placed directly under the device using a standard escape pattern. Others
may surround the part.
These capacitors should have a value of 0.01 or 0.1 µF. Only ceramic SMT (surface mount technology)
capacitors should be used to minimize lead inductance, preferably 0402 or 0603 sizes.
In addition, it is recommended that there be several bulk storage capacitors distributed around the PCB,
feeding the VDD, NVDD, GVDD, and LVDD planes, to enable quick recharging of the smaller chip
capacitors. These bulk capacitors should have a low ESR (equivalent series resistance) rating to ensure the
quick response time necessary. They should also be connected to the power and ground planes through two
vias to minimize inductance. Suggested bulk capacitors—100–330 µF (AVX TPS tantalum or Sanyo
OSCON).
Freescale Semiconductor
Decoupling Recommendations
shows the PLL power supply filter circuit.
MPC8315E PowerQUICC
VDD
Figure 63. PLL Power Supply Filter Circuit
10 Ω
™
2.2 µF
II Pro Processor Hardware Specifications, Rev. 0
GND
Figure
Low ESL Surface Mount Capacitors
2.2 µF
63, one to each of the AV
DD
AV
DD
pin being supplied to minimize
(or L2AV
DD
DD
)
System Design Information
pins. By providing
DD
107