dsp56167 Freescale Semiconductor, Inc, dsp56167 Datasheet - Page 79

• Manufacturer Part Number: dsp56167
• Description: Advance Information 16-bit Digital Signal Processor
• Manufacturer: Freescale Semiconductor, Inc

ELECTRICAL DESIGN CONSIDERATIONS
MOTOROLA
Use the following list of recommendations to assure correct DSP operation:
• Provide a low-impedance path from the board power supply to each V
• Provide a low-impedance path from the board ground to each V
• Use at least six 0.01–0.1 F bypass capacitors, positioned as close as possible to
• Ensure that capacitor leads and associated printed circuit traces that connect
• Use at least a four-layer PCB with two inner layers for V
• Because the DSP output signals have fast rise and fall times, PCB trace lengths
• When calculating capacitance, consider all device loads including parasitic
on the DSP.
the four sides of the package, to connect between the V
V
requirements for the codec circuitry.
to the chip V
the following section Analog I/O Considerations for special requirements for
the codec circuitry.
should be less than 6 inches maximum. This recommendation particularly
applies to the address and data buses, as well as the PS/DS, BS, RD, WR, R/
W, PEREN, IRQA, IRQB, IRQC, HEN, HR/W, and HACK pins.
capacitance due to PCB traces,. This is especially critical in systems with
higher capacitive loads that could create higher transient currents in the V
and V
SS
. Refer to the following section Analog I/O Considerations for special
This device contains protective circuitry to
guard against damage due to high static
voltage or electrical fields. However, normal
precautions are advised to avoid application
of any voltages higher than maximum rated
voltages to this high-impedance circuit.
Reliability of operation is enhanced if unused
inputs are tied to an appropriate logic voltage
level (e.g., either V
SS
circuits.
DD
and V
DSP56167/D, Rev. 1
SS
CAUTION
pins are less than 0.5 inch per capacitor lead.
SS
or V
DD
).
Electrical Design Considerations
DD
Design Considerations
DD
power source and
and V
SS
SS
pin.
. Refer to
DD
pin
DD
4-3