Analog MUX using discrete MOSFETs for flying capacitor cell measurement BMS

"piglet"  wrote in message news:oumboe$5ap$1@dont-email.me...

> The body diodes are pointing in the right direction, they always were. 
> What was wrong is the channel or substrate diodes are shown reversed. For 
> instance you have Q22 correct - it is a P-channel and so the arrow points 
> out of the substrate and towards the source. It is in fact just another 
> way of showing the parasitic body diode. But now look at the BSS84 
> symbols - those too are P-channel but the symbol on your design has their 
> substrate diode arrow pointing from source towards the back of the gate. 
> In other words the channel diode direction should point the same way as 
> the body diode (if drawn) the two arrows are showing the same thing and so 
> should point the same way. Likewise the symbols on your design for the 
> BSS138 which is an N-channel device have the body diode drawn right but 
> have the channel arrow pointing out the channel pointing to source - the 
> arrow should point into the channel. Look at how the On-Semi datasheets 
> for those parts correctly depict them. I think sometimes people get 
> confused between FETS and BJTs, on an NPN BJT the emitter arrow points 
> towards the outside world, not so with an N-channel fet!

Whew! I found out that my PADS Logic symbol editor was somehow corrupted. I 
would edit the symbol, but when I applied it to the schematic, it kept the 
old one. Now I think I finally have it right, and a made the arrow open 
rather than closed. I still like the body diode, but I see your point. 
Anyway, I have arranged the parts on a 2"x 6" board, and that isn't really 
very dense. I will be getting the prototypes made by www.eiconnect.com, 
originally zoompcb.com, and they have a deal where I have gotten 5" x 5" 
boards (maximum is 25 in^2) for $25 each. I am considering adding more 
circuitry to fill up a 4" x 6" board - perhaps my design using TL222 optos 
and one using one or two DG408 or DG409 analog switches.

Thanks,

Paul