16 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, as well as validating and testing their design

implementation to confirm system functionality.

16.1 Application Information

TMUX4821 and TMUX4819 are part of the beyond the supply switches and multiplexers family of devices.

This means that this device can switch signals from -15V to 15V with a low voltage supply from 1.8V to 5.5V.

Additionally, TMUX48xx features powered-off protection, which by design keeps the switches open even when

there is no supply. This unique feature combination enables the TMUX48xx to be extremely versatile for a wide

variety of applications such as boosted outputs and high common mode offsets.

16.2 Typical Applications

16.2.1 Audio Amplifier Switching

Often, there are multiple audio sources in a system giving the user options on which source will connect to the

speaker. To enable switching between these sources, a TMUX48xx can be used. The line-in can be biased to

a negative voltage, and class-D amplifier output can be higher than the typically used 3V and 5V supplies. So

any circuitry connected needs to handle this bipolar voltage. This same scheme can be used in systems where

there are multiple speaker outputs and one source as well. Here the switch is used to switch from an internal

speaker to an external one. Figure 16-1 shows the block diagram for these applications. Here a TLV320AIC3x is

used as an audio codec driving a TPA313x class D audio amplifier. Additionally, if IEC protection is needed on

the external connectors (audio jack input or external speaker), then a 2 channel TPD2E007 can be used.

The TMUX48xx can be used to switch up to ±15V with a supply voltage from 1.8V to 5.5V. The supply can also

be driven directly with a GPIO, allowing the user to put the device into ultra-low power mode. In this mode, the

TMUX48xx operates with powered-off protection, so any high voltage present on the inputs will not propagate to

the outputs. This feature allows for the correct power up cycling and increases system robustness. Additionally,

the TMUX48xx features excellent THD+N performance, so there is minimal impact to the audio signal quality

through the switch. This allows the system designer to save a significant portion of board area without impacting

signal integrity.

Class D Audio

Amplifier

TPA313x

SEL

VDD

Decoder

Audio Codec

TLV320AIC3253

L

R

GPIO

Class D Audio

Amplifier

TPA313x

Audio Codec

TLV320AIC3253

L

R

GPIO

SEL

VDD

Internal

External

TPD2E007

TPD2E007

Decoder

SEL

VDD

Decoder

Decoder

SEL

VDD

Figure 16-1. Audio Amplifier Switching

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TMUX4821, TMUX4819

SCDS487A – OCTOBER 2025 – REVISED DECEMBER 2025

Copyright © 2025 Texas Instruments Incorporated

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Product Folder Links: TMUX4821 TMUX4819