Specifications

ESS Technology, Inc. SAM0025A-062397 109
ES1879 DATA SHEET
APPENDIX E: LAYOUT GUIDELINES
PRELIMINARY
APPENDIX E: LAYOUT GUIDELINES
PCB Layout
Notebook, Motherboard, Pen-based, and PDA portable
computers have the following similarity in PCB layout
design:
6. Multi-layer (usually 4 to 8 layer).
7. Double-sided SMT.
8. CPU, corelogic (chip set), system memory, VGA
controller, and video memory reside in the same
PCB.
This is a very noisy environment for adding an audio
circuit. The following are the guidelines for PCB layout for
ESS
Audio
Drive
®
chip application.
Component Placement
The audio circuit-related components must be grouped in
the same area. The audio I/O jack and connector are
considered audio-related components as well. There are
two possible placements for these audio components:
A grouped on one side of the PCB.
B separated on both sides of the PCB.
In Case B, audio component grouping will take less space.
Analo
g
Ground Plane
Audio circuits require two layers of analog ground planes
for use as shielding for all analog traces.
In component placement case A (Figure 37), the first layer
of analog ground plane is on the analog component side,
the second analog ground plane is on the inner layer, and
the analog traces are embedded between these two
planes.
In component placement case B (Figure 38), the analog
ground planes are on both sides of the PCB, with the
analog traces shielded in the middle.
Case A:
Figure 37 Analog Components on One Side of the PCB
Case B:
Figure 38 Analog Components on Both Sides of the PCB.
Special Notes
The analog traces should be places as short as possible.
The MIC-IN circuit is the most sensitive of the audio
circuits, and requires proper and complete shielding.
Analog ground plane on analog component side
Inner one or two layer(s) for analog traces
Inner layer analog ground plane
Other layer(s) for digital traces
Components
Analog ground plane on component side
Inner layer(s) for analog traces
Analog ground plane on component side
Components
Components