dsp56167 Freescale Semiconductor, Inc, dsp56167 Datasheet - Page 83

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

MOTOROLA
Figure 4-4 shows that 0.1 F bypass capacitors should be located as close to the pins
being bypassed as possible. Connect the ground side of the bypass capacitors to V
by short traces.
The pins requiring 0.1 F bypass capacitors are VRDA, VRAD, and V
and the VDIV pin should have bypass capacitors of the largest size practical; 10 F
should be considered a minimum size for the larger capacitors (65 F may be used on
VDIV). The capacitors should be placed near the package, but do not have to be
immediately next to the pins. As shown in Figure 4-5 on page 4-8, run the DAC
outputs (SPKP and SPKM) next to each other.
If possible, use the output differentially. Shield analog signal traces by running traces
connected to the analog ground next to them. All unused board area (on both
interconnect levels) should be copper-filled and connected to analog ground. For
clarity and simplicity, copper fill is indicated by text, but not shown in. The ADC
input anti-aliasing filtering should be done with respect to VRAD.
Figure 4-6 on page 4-9 shows four examples of good power supply connections.
Figure 4-4 Suggested Top Layer Bypassing
0.1 F
15 F
DSP56167/D, Rev. 1
65 F
28
VRAD
AUX
MIC
0.1 F
0.1 F
15 F
0.1 F
15 F
Analog I/O Considerations
Design Considerations
DDA
. These pins
SSA
4-7