WORST

BETTER

BEST

1W min.

W

SN74AHC1G14

www.ti.com

SCLS321Q – MARCH 1996 – REVISED SEPTEMBER 2015

10 Power Supply Recommendations

The power supply can be any voltage between the minimum and maximum supply voltage rating listed in the

Recommended Operating Conditions table.

supply, a 0.1-

for each supply pin. To reject different frequencies of noise, use multiple bypass capacitors in parallel. Capacitors

with values of 0.1

μF and 1 μF are commonly used in parallel. The bypass capacitor must be installed as close

as possible to the power terminal for best results.

11 Layout

11.1 Layout Guidelines

Reflections and matching are closely related to the loop antenna theory but are different enough to be discussed

separately from the theory. When a PCB trace turns a corner at a 90° angle, a reflection can occur. A reflection

occurs primarily because of the change of width of the trace. At the apex of the turn, the trace width increases to

1.414 times the width. This increase upsets the transmission-line characteristics, especially the distributed

capacitance and self-inductance of the trace, which results in the reflection. Not all PCB traces can be straight;

therefore some traces must turn corners. Figure 7 shows progressively better techniques of rounding corners.

Only the last example (BEST) maintains constant trace width and minimizes reflections.

11.2 Layout Example

Figure 7. Trace Example

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