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they belong to digital logic families......
TTL is implemented using BJT and CMOS using p and n mosfet....
TTL has higher power dissipation than CMOS......
any digital book[morris mano,floyd,wakerley] will have details about this....
Now people when talking about TTL and CMOS they talk about the logic level, not much about technology.
flatulent may be wrong when saying that "TTL now obsolete and many manufacturers stop producing it", CMOS CD4000 series are at the same situation, guys.
TTL at the first stage was BJT ICs (7400 standard series), and CMOS, of course, CMOS.
TTL (7400 series): - higher power consumption, then low fan out (BJT version).
- high speed (tens or hundreds MHz).
- less noise immunity due to its logic level.
CMOS (CD4000 series): - low power consumption, high fanout. However, they consume power much when increasing frequency.
- low speed (a few MHz).
- better noise immunity.
- wide range of supply voltage.
Now manufacturers combine 2 pro features in one, for example: 74HC00, 74HCT00 series, they are CMOS but with TTL logic level, TTL pinout. So you can see TTL logic level must be lasted very long.
7400 series and CD4000 series are now obsolete. You can see them in the market with sources from, for examples, China manufacturers.
in few words
if you want high speed you can choose the ttl family IC
if you want the low power consumption you can choose the cmos family IC
you can find the same IC in the 2 families but of course with different names
1..transisstor cosumes power always whereas mosfet only during TRANSITION form conducting to non conducting and vice versa...
power consumption for CMOS is less than that of BJT
2..CMOS is immune to noise than BJT
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