2-channel

SPDT

V

CC

SEL

OE

COM1

COM2

GND

System

Controller

Port A

Port B

0.1 F

3.3 V

High Speed

Port

Switch

Control Logic

B1

B2

A1

A2

11

TMUX136

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SCDS367A – AUGUST 2017 – REVISED OCTOBER 2017

Product Folder Links: TMUX136

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Copyright © 2017, Texas Instruments Incorporated

9 Application and Implementation

NOTE

Information in the following applications sections is not part of the TI component

specification, and TI does not warrant its accuracy or completeness. TI’s customers are

responsible for determining suitability of components for their purposes. Customers should

validate and test their design implementation to confirm system functionality.

9.1 Application Information

9.2 Typical Application

There are many applications in which microprocessors or controllers have a limited number of I/Os. The

TMUX136 solution can effectively expand the limited I/Os by switching between multiple buses in order to

interface them to a single microprocessor or controller.

Figure 9. Typical Application

9.2.1 Design Requirements

The TMUX136 has internal 6-M

Ω pulldown resistors on SEL and EN, so no external resistors are required on the

logic pins. The internal pulldown resistor on SEL ensures PORT A channel is selected by default. The internal

pulldown resistor on EN enables the switch when power is applied to VCC.

9.2.1.1 Detailed Design Procedure

The TMUX136 can be properly operated without any external components. However, TI recommends that

unused pins must be connected to ground through a 50-Ω resistor to prevent signal reflections back into the

device.