How to Communicate I2S Signals Between MCU, DSPs, and Amplifiers Using Multiplexers

I2S (Inter-IC Sound Bus) is a serial bus interface used for connecting audio devices together. Typically, a three-line protocol consisting of a Serial Clock (SCK), Word Select (WS) and Serial Data (SD) lines is used for these applications, though the need for a Word Select line is not always needed. A multiplexer can be used to help support multiple audio peripherals using a single I2S bus. Since these are passive, bidirectional parts they give the user the ability to either multiplex (MUX) or demultiplex (DEMUX) the respective signals.

Figure 1 2-Channel Implementation of I2S Using SN3257-Q1

Figure 2 3-Channel Implementation of I2S Using TS5A23157-Q1

Design Considerations

Select multiplexers with enough bandwidth and the appropriate channel count to support the needs of the application.
Powered-off protection can help protect against voltages present on the inputs when the multiplexer is not powered.
For battery powered systems, select multiplexers with low supply current to maximize battery life.
Learn about multiplexer parameters with TI Precision Labs Videos.
Ask a question on our TI E2E™ Design Support Forum.

Table 1 Recommended Parts

Part Number	VCC Range (V)	Configuration	Bandwidth	R_ON (Ω)	Supply Current (μA)	Features
SN3257-Q1	1.5 to 5.5	2:1 4-channel	2.0 GHz	5	40	1.8-V compatible control inputs, break-before-make, fail-safe logic, powered-off protection
TS3A27518E-Q1	1.65 to 3.6	2:1 6-channel	240 MHz	4.4	0.04	1.8-V compatible control inputs, break-before-make, powered-off protection
TMUX1574	1.5 to 5.5	2:1 4-channel	2.0 GHz	2	40	1.8-V compatible control inputs, fail-safe logic, Integrated pulldown resistor on logic pin, powered-off protection, supports input voltage beyond supply
TS5A23157-Q1	1.65 to 5.5	2:1 2-channel	220 MHz	15	0.01	Break-before-make, low charge injection, functional safety capable

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