Depending on speed CMOS can be very low power which is really mandatory in battery powered applications.

 

Depending on speed CMOS can be very low power which is really mandatory in battery powered applications.

And in the quiescent state, they draw only a very small leakage current.

 

And in the quiescent state, they draw only a very small leakage current.

So aka clock speed = 0 Hz.
vis-a-vis MrAL: "Depending on clock speed".

 

Even though TTL was way before i was born, I do like the fact that you can build most simple IC's with just transistors, Combine that with how cheap and rugged a transistor is. id say the ic's are pretty obsolete for commercial use. But for a hobby project and if you have afew kicking about go for it

TTL uses about 100,000 times more power than cmos, However Cost, reliability & fixabilty are also important, I will quite happily lose some efficiency to increase the fixabilty and price point. I did a post on using transistors as a comparitor, But i need to work out some kinks if anyone wants to help .

 

I built an 8 digit frequency counter all 7400 TTL series, not 74LS but original 7400 series sometime late 1970's. It drew over 1 amp at 5 volts.
Sometime late 1980's early 1990's i converted it to 74ALS. Brought the current down drastically.
Also early 1990's i designed a 100MHz digital oscilloscope using the 74F family with interlaced memory clock. The memory i think was very fast CMOS, i dont remember the part numbers now.
Back around mid 1970 i worked for a company where we made precision weigh scales used for biology research (like for Pfizer in Canada for weighing animal internal organs). They were made with 99 percent original family 7400 series TTL. There were a LOT of those chips on big PC boards. Looking back, it was nuts. 14 and 16 pin DIP chips and small bypass caps lined the boards up and down in long rows, all WIRE WRAPPED on the back side (all wire wrap sockets)! Looking back, that was REALLY nuts!
In the 1980's we made high power frequency converters with all the digital circuitry 74LS commercial and 54LS series military. Both series were vary hardy and reliable so the military loved them (54LS00 series).

 

I do like the fact that you can build most simple IC's with just transistors

All these circuits use transistors.
Standard TTL uses BJT,s and CMOS uses MOSFETs.

 

So aka clock speed = 0 Hz.
vis-a-vis MrAL: "Depending on clock speed".

I was just emphasizing the point that CMOS draws not just low power, but essentially no power when in the quiescent state or 0 Hz clock speed (if there is a clock).

Is there some particular reason that you seem to nit-pick my comments that are related to your posts?

 

The CD4000 series is also slow, and that can be a good thing as there is less ringing on wires than with the modern stuff. CD4000 series is not buffered on its input so there is less "stuttering" on slowly rising edges. In genera thel CD4000 series is more forgiving of poor layout, long wires, unregulated power supplies and more kinds of problems.

 

I was just emphasizing the point that CMOS draws not just low power, but essentially no power when in the quiescent state or 0 Hz clock speed (if there is a clock).

Is there some particular reason that you seem to nit-pick my comments that are related to your posts?

I like to point out deficiencies in designs i was at one time actually employed to do that so i have a lot of experience with engineers who get bugged because someone is telling them that they overlooked something, some of them take it as good advice and roll their sleeves up and dig deeper down into the theory behind it, while some take constructive criticism as a personal mockery. The ones that dig down into it get better, the others dont.

But hey, you nit picked first

BTW, my father can beat up your father

 

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I hope you two kiss and make up. Both of you have different opinions. Different experiences leading you to different conclusions.

Like two bakers arguing over who has the better loaf of bread. Both are good. Enjoy feasting on both loafs.

 

But hey, you nit picked first

I don't see how that's a nit, but I guess my point is your nit.

 

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I hope you two kiss and make up. Both of you have different opinions. Different experiences leading you to different conclusions.

Like two bakers arguing over who has the better loaf of bread. Both are good. Enjoy feasting on both loafs.

I was taught to analyze the carp our of everything before it can be shipped. This makes you learn to catch things that can be overlooked. In control theory if the plane crashes you are going to feel very bad when you find out you did something wrong and didnt catch it before it became part of the product. Samsung recently had learned the hard way too when they had problems with one of their phone battery compartments. Lost a HUGE amount of money over something so simple.
If you look back in history you will find all kinds of errors like this where a simple analysis would have revealed the problem and it could have been corrected easily.

 

I don't see how that's a nit, but I guess my point is your nit.

I guess my only point is that none of us are completely error free so it is good to get peer review. In fact, i think we should welcome it not try to fight it off. I appreciated it when someone checks out something i did especially if there was a mistake somewhere.

 

I was taught to analyze the carp our of everything before it can be shipped. This makes you learn to catch things that can be overlooked. In control theory if the plane crashes you are going to feel very bad when you find out you did something wrong and didnt catch it before it became part of the product. Samsung recently had learned the hard way too when they had problems with one of their phone battery compartments. Lost a HUGE amount of money over something so simple.
If you look back in history you will find all kinds of errors like this where a simple analysis would have revealed the problem and it could have been corrected easily.

No need to explain yourself to me mate. I think constructive criticism is a good thing. Maybe you and all the brain boxs on here can lay your opinion on my project https://forum.allaboutcircuits.com/...-solar-charge-controller.169230/#post-1506539

 

Regarding the question,
what do you mean by "CMOS" , the 4000 series of chips ?

TTL used to be the Ti system, but for decades, TTL just tends to mean "digital", Most digital chips inside are a MOS of some form.
the only think that TTL now tends to imply is the output drive capability, and input thresholds, but even that is at best wooley ,

The old 4000 series were at the time ( 1980's ) , much more fragile than the then TTL , which had great big , resilient output transistors. Its was before the days of ESD, it had not been invented for most people, ESD straps were none existent,
So CMOS got the label that it was sensitive. Now days, most all chips have sensitive IO pins, ESD precautions are needed on all chips.

So ESD is not a reason to select any chip.

Power, CMOS 4000 chips can accept a wide Power voltage range, but now days so can most "TTL" chips.
amount of power, Yep Un buffered 4000 still has the record of low power, but the normal CMOS is much more equivalent to the TTL equivalent,

If its an FPGA, they have thigns like LVCMOS IO, which is a smooth mix of TTL and CMOS capabilities.

Reason to select 4000 series or "TTL" you ask ?
in my view unless you need the very low power of UB CMOS, stay with "TTL" ,

but it does not matter much,

 

Most CD4xxx Cmos ICs are buffered, but with a 5V supply the output current with 0.4V of saturation voltage is only ONE mA. It can drive a current of 4mA into a dead short.
An old 74xx TTL with its 5V supply has an output low current with 0.4V of saturation voltage is much higher at 16mA.
74HCxxx is higher speed and higher output current Cmos.

 

Most CD4xxx Cmos ICs are buffered, but with a 5V supply the output current with 0.4V of saturation voltage is only ONE mA. It can drive a current of 4mA into a dead short.
An old 74xx TTL with its 5V supply has an output low current with 0.4V of saturation voltage is much higher at 16mA.
74HCxxx is higher speed and higher output current Cmos.

Hi,

I think CDxxxx was the old family while CDxxxxB is the buffered.
Been a long time since i did anything with them though.

 

Very few CD4xxxx ICs are not buffered. The CD4069 hex inverter is not buffered and has the same output current as a CD4xxxxB gate that is buffered.
Here are graphs from their datasheets. Look at the dismal output current when the supply is 5V, it is even less with a 3V supply.

 

Very few CD4xxxx ICs are not buffered. The CD4069 hex inverter is not buffered and has the same output current as a CD4xxxxB gate that is buffered.
Here are graphs from their datasheets. Look at the dismal output current when the supply is 5V, it is even less with a 3V supply.

Did they upgrade the entire line perhaps?

 

I like CD4000 CMOS over BJT TTL because it has a much higher operating voltage range, and it has a very high input impedance, so is easy to interface to other devices or add a signal delay with low values of capacitance.