5 Nov
2011
5 Nov
'11
3:53 p.m.
On Nov 5, 2011, at 5:12 PM, Tony Duell wrote:
Well, yes. I like that they're just switches. Buffers have their place, of course,
but sometimes it's nice to have a little DIP IC that'll switch off your headphone
port without clicking too much. They're fundamentally different devices.
I actually found the 4052 great for muxing a UART channel 4 ways because you didn't
have to use 2 chips; the Rx and Tx were treated equally because they were just
transmission gates. It would only ever be good if you were on the same PCB (or at least
not going too far), but that was what I was doing, so it was great.
They're also not particularly fast, but at least for what I was using them for, they
didn't need to be. As with anything, it's a matter of understanding the
limitations. :-)
- Dave
And I sure
love the 405x series of (basically) analog multiplexers and
4016 analog switches. By now there are a number of better analog
multiplexers and switches out there, but there weren't any straight TTL
muxes that I remember which operate in both directions (because they
were typically combinational logic instead of pass gates).
True (although IIERC some of these exist in 74HC etc).
But rememebr a digital multiplexer (like the 74x151) performs a buffering
function too -- the input is 1 TTL load, the output will drive at least
10 simialr loads. This is obviously not true of the analogue
multiplexers, which are trasnmission gates. This can be important.
And it's why you can't use 4016s, etc as bidirecitonal data bus buffers.
They perform no buffering at all.