Operating a CMOS switching structure

[beak]

Hi.&nbsp;&nbsp;I am trying to implement a low cost (&lt;$4 (1,000s of pieces)) solution to selectively (16 different levels)attenuate a line level audio signal similar to the way a wirewound potentiometer would be used.... I only have digital control capabilities available (the available digital pots that I have found can't handle the signal (0.5 W into a 45 ohm speaker)).<br><br>Tentatively, I have implemented four CMOS switches in parallel.&nbsp;&nbsp;The structure of one is described below.&nbsp;&nbsp;The question then, is: is there a known standard method of using a 0 to 3V digital system to turn both transistors on (+3V ---&gt; -3 for the PMOS, +3 for the NMOS).&nbsp;&nbsp;Both transistors are off at 0V.<br><br>Circuit:<br>Node 1: Line audio in, R1/1<br>Node 2: R1/2, D1/Anode, D2/Cathode<br>Node 3: D1/Cathode, Qn/Drain<br>Node 4: Qn/Source, Spkr/1, Qp/Source<br>Node 5: D2/Anode, Qp/Drain<br>Node 6: Qn/Gate (0V=OFF, +V=ON)<br>Node 7: Qp/Gate (0V=OFF, -V=ON)<br>*Nodes 6 & 7 are the subject of this question.. I would like to operate them simultaneously (0V=OFF, +V=ON).<br><br>** Three more identical structures will be used in parallel with the above described structure.&nbsp;&nbsp;The 6/7 node will be controlled by a separate digital control line on each structure.<br>Beak --- 7/8/2000<br>