9 Detailed Description

9.1 Overview

The TMUX1308 is an 8:1, single-ended (1-channel), mux. The TMUX1309 is a 4:1, differential (2-channel) mux.

Each channel is turned on or turned off based on the state of the address lines and enable pin.

9.2 Functional Block Diagram

TMUX130 8

A0

A1

A2

EN

S1

D

S2

S3

S4

S5

S6

S7

S0

1-OF-8

DECODER

TMUX130 9

S0A

DB

S1A

S2A

S3A

S0B

S1B

S2B

S3B

DA

A0

A1

EN

1-OF-4

DECODER

9.3 Feature Description

9.3.1 Bidirectional Operation

The TMUX1308 and TMUX1309 devices conduct equally well from source (Sx) to drain (Dx) or from drain (Dx)

to source (Sx). Each signal path has very similar characteristics in both directions so they can be used as both

multiplexers and demultiplexer to support both analog and digital signals.

9.3.2 Rail-to-Rail Operation

The valid signal path input and output voltage for the TMUX1308 and TMUX1309 ranges from GND to VDD.

9.3.3 1.8 V Logic Compatible Inputs

The TMUX1308 and TMUX1309 support 1.8-V logic compatible control for all logic control inputs. The logic

input thresholds scale with supply but still provide 1.8-V logic control when operating at 5.5-V supply voltage.

1.8-V logic level inputs allows the multiplexers to interface with processors that have lower logic I/O rails and

eliminates the need for an external voltage translator, which saves both space and BOM cost. The current

consumption of the TMUX1308 and TMUX1309 devices increase when using 1.8-V logic with higher supply

voltage. For more information on 1.8-V logic implementations, refer to Simplifying Design with 1.8 V logic Muxes

and Switches.

9.3.4 Fail-Safe Logic

The TMUX1308 and TMUX1309 device have Fail-Safe Logic on the control input pins (EN, A0, A1, and A2)

allowing for operation up to 5.5-V, regardless of the state of the supply pin. This feature allows voltages on the

control pins to be applied before the supply pin, protecting the device from potential damage. Fail-Safe Logic

minimizes system complexity by removing the need for power supply sequencing on the logic control pins. For

example, the Fail-Safe Logic feature allows the select pins of the TMUX1308 and TMUX1309 to be ramped to

5.5-V while VDD = 0-V. Additionally, the feature enables operation of the multiplexers with VDD = 1.8-V while

allowing the select pins to interface with a logic level of another device up to 5.5-V, eliminating the potential need

for an external voltage translator.

TMUX1308, TMUX1309

SCDS426E – MARCH 2020 – REVISED OCTOBER 2022

www.ti.com

22

Submit Document Feedback

Copyright © 2022 Texas Instruments Incorporated

Product Folder Links: TMUX1308 TMUX1309