Pages: 1 [2]   Go Down
Author Topic: CMOS vs TTL  (Read 5320 times)
0 Members and 1 Guest are viewing this topic.
0
Offline Offline
Shannon Member
****
Karma: 214
Posts: 12406
Arduino rocks
View Profile
 Bigger Bigger  Smaller Smaller  Reset Reset

Of course CMOS scales to much faster clock rates with smaller processes and lower voltages - a 1.8V CMOS logic family would be interesting.

I have an old Sci Am special on microelectronics, published some time in the 80's - they forecast that I2L (integrated injection logic) would take over from MOSFET technology.  Never happened!

The other feature of TTL that ought to be mentioned is that the static power dissipation of gates is many orders of magnitude higher than CMOS (factor of millions I think) - this means TTL cannot be used for VLSI at all since the quiescent power dissipation would be measured in kW and MW.  A chip with 50 TTL gates on it is feasible, with a million gates: totally impossible.
Logged

[ I won't respond to messages, use the forum please ]

Wisconsin
Offline Offline
Edison Member
*
Karma: 4
Posts: 1001
I LOVE THIS STUFF!!!!
View Profile
WWW
 Bigger Bigger  Smaller Smaller  Reset Reset

Aren't FTDI chips TTL?  Such as the one and the arduino Duemilanove?
Logged

Accelerate to 88 miles per hour.

Show Your Work
Offline Offline
Edison Member
*
Karma: 14
Posts: 1108
View Profile
 Bigger Bigger  Smaller Smaller  Reset Reset

Aren't FTDI chips TTL?  Such as the one and the arduino Duemilanove?

You mean this part?

http://www.ftdichip.com/Support/Documents/DataSheets/ICs/DS_FT232R.pdf

Though it interfaces CMOS to TTL, I can't see it being TTL.  Maybe BiCMOS?  The datasheet does not what technology the chip is made from.
Logged

I have only come here seeking knowledge. Things they would not teach me of in college.

Left Coast, CA (USA)
Offline Offline
Brattain Member
*****
Karma: 361
Posts: 17301
Measurement changes behavior
View Profile
 Bigger Bigger  Smaller Smaller  Reset Reset

Aren't FTDI chips TTL?  Such as the one and the arduino Duemilanove?

I think you would be hard pressed to find any mass produced IC developed in the last 10 years (perhaps even longer) that is bipolar (as pure TTL is based on) tech, rather then the various CMOS derived tech. Once they got the speed and output drive to be competitive with bipolar TTL, the other overwhelming features of CMOS made it the mainstream tech to use in IC development. I think newer bipolar IC designs are probably only used in few low volume specialized niche applications, it at all?
Logged

Pages: 1 [2]   Go Up
Jump to: