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TMUX1101, TMUX1102

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SCDS410 – MARCH 2019

Product Folder Links: TMUX1101 TMUX1102

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Copyright © 2019, Texas Instruments Incorporated

11 Power Supply Recommendations

The TMUX110x operate across a wide supply range of 1.08 V to 5.5 V. Do not exceed the absolute maximum

ratings because stresses beyond the listed ratings can cause permanent damage to the devices.

other components. Good power-supply decoupling is important to achieve optimum performance. For improved

Place the bypass capacitors as close to the power supply pins of the device as possible using low-impedance

connections. TI recommends using multi-layer ceramic chip capacitors (MLCCs) that offer low equivalent series

resistance (ESR) and inductance (ESL) characteristics for power-supply decoupling purposes. For very sensitive

systems, or for systems in harsh noise environments, avoiding the use of vias for connecting the capacitors to

the device pins may offer superior noise immunity. The use of multiple vias in parallel lowers the overall

inductance and is beneficial for connections to ground planes.

12 Layout

12.1 Layout Guidelines

12.1.1 Layout Information

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 and therefore some traces must

turn corners.Figure 11 shows progressively better techniques of rounding corners. Only the last example (BEST)

maintains constant trace width and minimizes reflections.

Figure 11. Trace example

Route high-speed signals using a minimum of vias and corners which reduces signal reflections and

impedance changes. When a via must be used, increase the clearance size around it to minimize its

capacitance. Each via introduces discontinuities in the signal’s transmission line and increases the chance of

picking up interference from the other layers of the board. Be careful when designing test points, through-

hole pins are not recommended at high frequencies.