MAX45711


I'm trying to use the MAX4571 essentially to mute some audio channels,

http://www.maxim-ic.com/quick_view2.cfm?t=qv&qv_pk=1974#Applications%2FUses

I got the controller to work and it seems fine. My test was to put V+ on the
input and scope the output(with a pull down to ground for when the switch is
off). It seems to work fine. My code simply toggles the state the switches
every 1s or so.

But when I put an audio signal on the input instead I get the negative half
clipped and it is extremely attentuated(About 1/10 or more). What I did was
actually pass a sin wave generated by my computer which goes into a
mixer(for easy volume control and other things that I tend to do) then from
the mixer's headphone out into the input of the MAX4571.



Audio+ --- MAX4571 NO1

MAX4571 COM1 ---+--- Audio-
R
|
GND

(R anywhere from 500 to 3k but didn't help any and made it worse for lower
and high values)

With the scope connected to +.

Any ideas why the signal would be clipped and severly attenuated?

Its possible I ruined the device. For some reason my first PIC's I2C
channels stopped working so I might have shorted something out when I was
probing around. I replaced the pic and everything seemed to work but maybe I
screwed up the MAX4571 although it will passes the constant voltage just
fine.

First thing I need to know is if it passes AC completely(the scope says no
and the data*** doesn't mention it except that its "audio").

Any potential ideas to try out? I guess the next step is to try another IC
but maybe there is something else going on here that I'm not seeing?

My concept how how it works is that I should just be able to put an audio
signal on the input and it will mute it when I tell it too. Maybe I have to
worry about input and output impedence too to get it to work properly?

Thanks,
Jon


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