MAX4908EBC+T

Analog Switches - Special Purpose Overview

The MAX4908EBC+T is a dual 3:1 clickless audio multiplexer manufactured by Analog Devices Inc./Maxim Integrated. It operates from a single +1.8V to +5.5V supply and features negative-signal capability, allowing signals as low as VCC - 5.5V to pass without distortion. The device includes internal shunt resistors on all input terminals to reduce click-and-pop sounds during switching. Key electrical parameters include a typical on-resistance of 0.38Ω, a maximum channel-to-channel matching of 0.1Ω, and a typical supply current of 2µA at +5.5V. It utilizes two digital control inputs (CB1, CB2) for signal selection and offers high power-supply rejection ratio (PSRR).

Analog Switches - Special Purpose Feature Summary

• Negative-signal throughput capability down to VCC - 5.5V for distortion-free operation.
• Internal shunt resistors on all input terminals to automatically discharge capacitance and suppress audible click-and-pop sounds.
• Break-before-make switching feature prevents momentary connection of old and new signal paths.
• Digital control inputs accept up to +5.5V independent of the supply voltage.

Analog Switches - Special Purpose Applications

• Cell Phones
• PDAs and Handheld Devices
• Notebook Computers
• MP3 Players

Analog Switches - Special Purpose Procurement Notes

Verify the specific package type required for the design, as the MAX4908 series is available in both 14-pin TDFN-EP and 12-bump WLP packages. Confirm that the ordering suffix corresponds to the desired physical footprint and tape/reel configuration. Ensure compatibility with the system's logic levels, noting that control inputs tolerate up to +5.5V regardless of the analog supply voltage.

Analog Switches - Special Purpose Selection Notes

Select the MAX4908 variant specifically when internal shunt resistors are required on all input terminals for comprehensive click-and-pop suppression. Compare against the MAX4909 if predischarge switching is not needed on specific channels, or the MAX4932 if no shunt resistors are desired. Consider the low on-resistance and flatness for bidirectional audio signal routing applications requiring minimal signal degradation.

Analog Switches - Special Purpose Part Context

The MAX4908 is part of the MAX4908/MAX4909/MAX4930/MAX4932 family of dual 3:1 clickless audio multiplexers. These devices share common architecture but differ in the presence and location of internal shunt resistors. The MAX4908 is distinguished by having shunt resistors on all input terminals, providing maximum noise reduction during switching events compared to other members of the series.

Analog Switches - Special Purpose Replacement Considerations

MAX4909ETD+T, MAX4930ETD+T, MAX4932ETD+T

Analog Switches - Special Purpose FAQ

How does the MAX4908 handle signals below ground potential?

The device features negative-signal capability, allowing it to pass signals as low as VCC - 5.5V through the switches without distortion.

What mechanism reduces audible clicks and pops in the MAX4908?

It uses internal shunt resistors on all input terminals to automatically discharge capacitance when terminals are not connected, combined with a break-before-make switching feature.

Can the digital control inputs operate at voltages higher than the analog supply?

Yes, the digital control inputs (CB1 and CB2) can accept up to +5.5V independent of the supply voltage, allowing for mixing of logic levels.