Audio Codec

Audio Ampli er

PreAmp

Microphone

Telecoil (T-coil)

Figure 9-2. Hearing Aid Telecoil MUX

9.2.1.1 Design Requirements

Table 9-1. Design Parameters

PARAMETERS

VALUES

Supply (VDD)

1.8 to 5.5 V

MUX I/O signal range (VS, VD)

-5.5 V to 5.5 V (Beyond the Supply)

Control logic thresholds (VSEL)

1.8 V to 5.5 V

9.2.1.2 Detailed Design Procedure

The TMUX2889 can support bidirectional signals beyond the supply without any external components except for

the supply decoupling capacitors. For how the signal range is above and below the device supply range, refer

to Section 8.3.1. Additionally with a very low on-resistance and an ultra flat response, the TMUX2889 has a

very low THD+N as well as a reduced impact to DC losses and thermal self-heating. These features make the

TMUX2889 an excellent choice for audio applications. For a more detailed analysis of the audio output switching

system, refer to Section 9.2.1.3.

9.2.1.3 Application Curve

The low on-resistance and ultra flat response enable the TMUX2889 to have an extremely low THD+N. This

results in little to no impact in audio fidelity, even in high performance systems. This allows the system designed

to save a significant portion of board area without impacting signal integrity.

Frequency (Hz)

20 30 4050 70 100

200 300 500

1000

2000

5000 10000 20000

0

0.0005

0.001

0.0015

0.002

0.0025

0.003

0.0035

600 Ohm

32 Ohm

16 Ohm

8 Ohm

4 Ohm

.

Figure 9-3. THD+N with Different Loading Conditions

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TMUX2889

SCDS464 – JUNE 2023

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