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ICS1531 Datasheet, PDF (58/76 Pages) Integrated Circuit Systems – Triple 8-bit MSPS A/D Converters with Line-Locked Clock Generator | |||
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ICS1531 Data Sheet - Preliminary
Chapter 8 Layout and Power Considerations
Chapter 8 Layout and Power Considerations
8.1 Layout Considerations
8.1.1 General Guidelines for Printed Circuit Board Layout
To lay out a printed circuit board that uses the ICS1531, see Figure 8-1 and use the following general
guidelines.
⢠Use a printed circuit board with at least the following four planes:
â One power plane
â One ground plane. (No special cutouts required.)
â Two signal planes
⢠Power supply voltages:
â Provide all supply voltages from a common source.
â Ensure that all supply voltages ramp together.
â Bypass each power supply pin with a 0.1-µF capacitor.
⢠When using capacitors for filtering or decoupling, use either tantalum or ceramic capacitors with good
high-frequency characteristics. (Do not use electrolytic capacitors.) Place the capacitors as close as
possible to the ICS1531 pins that are being filtered or decoupled.
⢠Trace widths:
â Use nominal trace widths of approximately 0.020 to 0.025 cm.
â Use a maximum trace width of approximately 0.076 cm.
⢠As Figure 8-1 indicates, connect the appropriate VDDx and VSSx pins to the appropriate plane, using
multiple surface-etched vias.
⢠Ensure that the area of the printed circuit board where the ICS1531 is placed is free of contaminants.
(Flux and other board-surface debris can degrade the performance of the external loop filter.)
Figure 8-1. General Decoupling Circuit for ICS1531
ICS1531
VDDx
2.54 cm max
1.27 cm max
0.1 µF
Ferrite bead Multiple vias
FB
0.1 µF
VCC
+
10 µF
VSSx
Width from ~
0.025 to
0.076 cm
Multiple vias
ICS1531 Rev N 12/1/99
Copyright © 1999, Integrated Circuit Systems, Inc.
All rights reserved.
58
December, 1999
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