Through looking at logic IC's on Mouser , I found this "new" Logic Family: HCS ,
next gen HCMOS.
Maybe not audio related , but I'm sure some of us older guys still use discrete
HCMOS IC's for controling audio relays and switches.
From their site :
The HCS family is an update to the HC logic family. HCS logic modernizes
multi-gate logic functions to meet the needs and demands on today’s system
designers. Each HCS logic part, numbered SN74HCSxx, is a pin-to-pin drop-in replacement for existing HC logic parts, with no need to update designs or change development tools.
The HCS family was designed with automotive applications in mind and is the first TI logic family to launch with a complete line of both commercial- and
automotive-grade parts.
https://e2e.ti.com/blogs_/b/analogwire/archive/2019/11/12/achieve-simpler-and-more-robust-designs
I must be missing something : "complete line of both commercial- and
automotive-grade parts" . A whole family seems a bit much , only 25 on their site
gates , flipflops , buffers, encoders/decoders.
Quiescent current (IQ) for an HCS part is just 2 µA max, compared to 20 µA max for comparable HC logic. Each device in the 2-V to 6-V HCS family consumes 95% less power than its equivalent HC logic function, making HCS logic devices much more suitable for battery-powered designs.
They say quiescent current of just 2 uA , but that is low freq or not doing much.
https://www.ti.com/sitesearch/docs/universalsearch.tsp?searchTerm=74HCS#q=74
HCS&t=everything&linkId=1
When I look at the data sheets , lower quiescent , extended temperature like 54HC
-40 to 125C, and all Schmitt trigger inputs.
Of course 74HCS00 = 74HC132 but with lower current , ext temp
74HCS04 with ST is 74HC14 is 74HCS14
74HCS32 = 74HC7032
74HCS08 = 74HC7001 and so on.
When I compare datasheets , it seems the hysteresis is smaller than regular HC. A
few ns faster but power dissipation capitance per gate the same.
I haven't had the chance of getting my hands on them and do some testing .
Has anybody used them ?
Is the current less , near the trigger points ?
It seems like a very interesting upgrade , no HCT , but who still uses that ?
Schmitt trigger inputs are the best. And about the same price as the regular HCmos.
next gen HCMOS.
Maybe not audio related , but I'm sure some of us older guys still use discrete
HCMOS IC's for controling audio relays and switches.
From their site :
The HCS family is an update to the HC logic family. HCS logic modernizes
multi-gate logic functions to meet the needs and demands on today’s system
designers. Each HCS logic part, numbered SN74HCSxx, is a pin-to-pin drop-in replacement for existing HC logic parts, with no need to update designs or change development tools.
The HCS family was designed with automotive applications in mind and is the first TI logic family to launch with a complete line of both commercial- and
automotive-grade parts.
https://e2e.ti.com/blogs_/b/analogwire/archive/2019/11/12/achieve-simpler-and-more-robust-designs
I must be missing something : "complete line of both commercial- and
automotive-grade parts" . A whole family seems a bit much , only 25 on their site
gates , flipflops , buffers, encoders/decoders.
Quiescent current (IQ) for an HCS part is just 2 µA max, compared to 20 µA max for comparable HC logic. Each device in the 2-V to 6-V HCS family consumes 95% less power than its equivalent HC logic function, making HCS logic devices much more suitable for battery-powered designs.
They say quiescent current of just 2 uA , but that is low freq or not doing much.
https://www.ti.com/sitesearch/docs/universalsearch.tsp?searchTerm=74HCS#q=74
HCS&t=everything&linkId=1
When I look at the data sheets , lower quiescent , extended temperature like 54HC
-40 to 125C, and all Schmitt trigger inputs.
Of course 74HCS00 = 74HC132 but with lower current , ext temp
74HCS04 with ST is 74HC14 is 74HCS14
74HCS32 = 74HC7032
74HCS08 = 74HC7001 and so on.
When I compare datasheets , it seems the hysteresis is smaller than regular HC. A
few ns faster but power dissipation capitance per gate the same.
I haven't had the chance of getting my hands on them and do some testing .
Has anybody used them ?
Is the current less , near the trigger points ?
It seems like a very interesting upgrade , no HCT , but who still uses that ?
Schmitt trigger inputs are the best. And about the same price as the regular HCmos.
I use HC's, 7474 in particular, for remembering fault conditions & driving LED & transistor outputs. 4 ma drive is important to me, waay better than 4013 etc. Pity they were only specified @ 5v, 12 v is a lot easier to come by in an amplifier.
The low current of hcs series is not important to me. The power supply of the amp I protected could put out 55 A @ 85 v. The power rails were flying though, both channels not at the same voltage, which is why I had to use optocouplers to communicate the fault conditions to the common fault remember/relay driver network on 5 vdc.
The low current of hcs series is not important to me. The power supply of the amp I protected could put out 55 A @ 85 v. The power rails were flying though, both channels not at the same voltage, which is why I had to use optocouplers to communicate the fault conditions to the common fault remember/relay driver network on 5 vdc.
^ 5V or 12V , does that matter ? A 7805 regulator and you're fine.
Optocouplers are great for driving high current/voltage switches from low voltage HCmos.
I used 12 of them just for switching and detecting voltages in my HPamp to the HCmos circuits.
2uA or 20 uA is not going to make much difference , for what we use them here , it will be low frequency so negligible. The all schmitt trigger inputs are more important , to tackle low input voltages.
I use the 74HC74 too . I had designed it with the Philips in mind that had ST clk inputs , but I had to use T.I's that don't , so it jittered with a slow clockpuls .
Optocouplers are great for driving high current/voltage switches from low voltage HCmos.
I used 12 of them just for switching and detecting voltages in my HPamp to the HCmos circuits.
2uA or 20 uA is not going to make much difference , for what we use them here , it will be low frequency so negligible. The all schmitt trigger inputs are more important , to tackle low input voltages.
I use the 74HC74 too . I had designed it with the Philips in mind that had ST clk inputs , but I had to use T.I's that don't , so it jittered with a slow clockpuls .
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Joined 2009
Paid Member
I switched over to programmable devices 25 years ago. PALS, GALS and CPLDs. I can't remember the last time
I used a 7400 series device. Oh, I do. It was a top octave generator for an electronic organ. The tuning
was finally good enough to be called an musical instrument and not an appliance. The 32 MHz master
clock needed "F" series chips to do 8 and 12 bit synchronous counters. Back then I learned a cute trick from
looking at Ampex designs in time base correctors. To do divide by N counters, most folks start at 0 and decode
for N to generate the reset pulse. The Ampex guys were using the preset already in the chip and use the
rollover pulse to trigger the preload which was set to max count minus N. Needs far fewer chips to get
weird count values.
Now for control systems an Arduino has decent horse power and if you get the logic wrong, you just erase and
fix the program.
Thanks for the info.
G²
I used a 7400 series device. Oh, I do. It was a top octave generator for an electronic organ. The tuning
was finally good enough to be called an musical instrument and not an appliance. The 32 MHz master
clock needed "F" series chips to do 8 and 12 bit synchronous counters. Back then I learned a cute trick from
looking at Ampex designs in time base correctors. To do divide by N counters, most folks start at 0 and decode
for N to generate the reset pulse. The Ampex guys were using the preset already in the chip and use the
rollover pulse to trigger the preload which was set to max count minus N. Needs far fewer chips to get
weird count values.
Now for control systems an Arduino has decent horse power and if you get the logic wrong, you just erase and
fix the program.
Thanks for the info.
G²
^ I never had scholing for electronics , so PALS, GALS , CPLDs and uP's are over my head.
Since the end of the eighties , I've been using Cmos 4000 & HCmos logic and Eproms and I love designing circuits with them even if one uP can replace them all .
Now there is more choice than ever , but HC is still my favorite.
Of course in SMD , no DIL ... for logic DIL is so seventies or eighties.
I even tried TSSOP , still doable but best is SOP /SOIC.
I meant : slow input voltages.
Here's T.I.'s logic families :
Since the end of the eighties , I've been using Cmos 4000 & HCmos logic and Eproms and I love designing circuits with them even if one uP can replace them all .
Now there is more choice than ever , but HC is still my favorite.
Of course in SMD , no DIL ... for logic DIL is so seventies or eighties.
I even tried TSSOP , still doable but best is SOP /SOIC.
I meant : slow input voltages.
Here's T.I.'s logic families :
Attachments
Like they'd spend big money tooling up for chips noone's going to buy in quantity - this is the 21st century and no electronics manufacturing uses DIL chips any more. Breakout boards are the way to go.
^ T.I. doesn't specify with proces they use . It's not going be be 5nm .
Not more complex , just Schmitt trigger inputs .
Keeping the 2-6 V , suggests not much smaller process , but a little so that the quiescent current is less .
Seems no-one here has tested them , not just for current draw at the threshold levels , but also at higher freq like 10 to 50 Mhz. Power dissipation capitance per gate suggests there won't be much difference between HC and HCS.
Can you use them "in odd "linear" ways" with ST inputs ? I think not.
.Not more complex , just Schmitt trigger inputs .
Keeping the 2-6 V , suggests not much smaller process , but a little so that the quiescent current is less .
Seems no-one here has tested them , not just for current draw at the threshold levels , but also at higher freq like 10 to 50 Mhz. Power dissipation capitance per gate suggests there won't be much difference between HC and HCS.
Can you use them "in odd "linear" ways" with ST inputs ? I think not.
^ I thought you meant with : linear" using it as amplifier .
If you want more than 4 mA output of HC/HCS , check out these babies: SN74LVC1G17.
Buffer with ST input and up to 38mA output at 5,5 V and faster too, around 1 ns ! 4 ns max.
Usually 74LVC is max 3,6 V , this one 5,5 V.
Very tiny package with 5 legs. Smaller than making a buffer with 2 mosfets like 2N7002 and a P channel, for the same price if you can buy them cheap. I did .
Ideal for after a RC timing to power a relay.
If you want more than 4 mA output of HC/HCS , check out these babies: SN74LVC1G17.
Buffer with ST input and up to 38mA output at 5,5 V and faster too, around 1 ns ! 4 ns max.
Usually 74LVC is max 3,6 V , this one 5,5 V.
Very tiny package with 5 legs. Smaller than making a buffer with 2 mosfets like 2N7002 and a P channel, for the same price if you can buy them cheap. I did .
Ideal for after a RC timing to power a relay.
Attachments
^ TTL was not for me. Strictly CMOS .
I still have unused logic IC's with dates on them from end eighties.
I wonder if they ever have a "use before" date.
There were differences in speed , current draw ,... between different manufactors.
My favorite are/were Philips HEF4000 & PC 74HC.
Though RCA's 74HC132 was the best for oscillators , lower current draw.
I still have unused logic IC's with dates on them from end eighties.
I wonder if they ever have a "use before" date.
There were differences in speed , current draw ,... between different manufactors.
My favorite are/were Philips HEF4000 & PC 74HC.
Though RCA's 74HC132 was the best for oscillators , lower current draw.
Attachments
+1
Judging by the amount of oxidation on the pins of the 74xx and 40xx logic ICs I've bought at Mouser recently, the DIP/DIL chips are very slow movers.
Looks like they come in SOIC. Those are definitely solderable by hand. The TSSOP is harder, but not impossible.
Tom
Yes, for every technology, there were small differences. Fairchild usually was faster. National less consistent. TI pretty predictable and so on. It only gave problems in a bad design where race conditions could cause glitches.
No I still haven't bought HCS IC's.
Ordering from outside of the country has problems for me because of payment issues , delivery and import taxes , so it takes a lot of thought to make an order to buy from a company like TI or Mouser. I had to do some more research about HCS and do some re-testing of HCMOS and I had and some new LVC gates I could buy from a local webshop at prices you would only get when buying a 1000 or more.
Good projects to do are very hard to come by these days if you're not into uP/uControlers like practically everything magazines like Elektor have to offer since 1995. So I have to order things I might want to use , and do want to test out.
There is a lot of choice in logic IC's !
TI's 74HCS really drew my interest back into this old love of mine : CMOS LOGIC. I had to research what more is out there !
Sure some of the advanced logic families go back to late 80's (AC - ACT) , others were intruduced in the 90's and some even more recent.
In the 90's they were not readily available to hobbyists like me or at a premium price so I didn't bother. I had used 74AC11074 as a freq divider at the front end of a freq counter and tested the 74AC11000 , both with the weird penning because of ground bounce. 74AC is now overschadowed by much better types although there are some more devices like counters available in AC-ACT and not the others.
Back in 2004 I started with computers and it pulled me away from DIY electronics, moving to a different country changed my life style . Only in 2019 I picked up electronics again , so while some logic families are decades old for you , they are spanking new to me. HCMOS has all you need at good speeds , even de 4000 series is good enough , or is it ?
So what to choose ?
BiCMOS is out for me , consumes too much and is more for bus drivers.
Bipolar TTL never sparked my interest , neither did TTL input levels in the various CMOS families.
Then there are Schmitt trigger inputs ! I love them . They can handle slow input voltages like RC's for timing or PUR (power-up-reset or sets) , RC delays .
But it comes at a price : they consume more than non ST at the same frequency (higher Cpd) and have just a little slower propagation delay although both depend a lot on the manufacturer.
In comes TI with HCS ! All input have ST , are faster than HC and if you believe the datasheets , all gates have an Cpd of 10 pF, which is much better than HC and no HCST with low level TLL inputs . Ideal you say ?
Ordering from outside of the country has problems for me because of payment issues , delivery and import taxes , so it takes a lot of thought to make an order to buy from a company like TI or Mouser. I had to do some more research about HCS and do some re-testing of HCMOS and I had and some new LVC gates I could buy from a local webshop at prices you would only get when buying a 1000 or more.
Good projects to do are very hard to come by these days if you're not into uP/uControlers like practically everything magazines like Elektor have to offer since 1995. So I have to order things I might want to use , and do want to test out.
There is a lot of choice in logic IC's !
TI's 74HCS really drew my interest back into this old love of mine : CMOS LOGIC. I had to research what more is out there !
Sure some of the advanced logic families go back to late 80's (AC - ACT) , others were intruduced in the 90's and some even more recent.
In the 90's they were not readily available to hobbyists like me or at a premium price so I didn't bother. I had used 74AC11074 as a freq divider at the front end of a freq counter and tested the 74AC11000 , both with the weird penning because of ground bounce. 74AC is now overschadowed by much better types although there are some more devices like counters available in AC-ACT and not the others.
Back in 2004 I started with computers and it pulled me away from DIY electronics, moving to a different country changed my life style . Only in 2019 I picked up electronics again , so while some logic families are decades old for you , they are spanking new to me. HCMOS has all you need at good speeds , even de 4000 series is good enough , or is it ?
So what to choose ?
BiCMOS is out for me , consumes too much and is more for bus drivers.
Bipolar TTL never sparked my interest , neither did TTL input levels in the various CMOS families.
Then there are Schmitt trigger inputs ! I love them . They can handle slow input voltages like RC's for timing or PUR (power-up-reset or sets) , RC delays .
But it comes at a price : they consume more than non ST at the same frequency (higher Cpd) and have just a little slower propagation delay although both depend a lot on the manufacturer.
In comes TI with HCS ! All input have ST , are faster than HC and if you believe the datasheets , all gates have an Cpd of 10 pF
, which is much better than HC and no HCST with low level TLL inputs . Ideal you say ?Now Cpd is a chapter on itself !
For me there are only the two big ones : TI , Texas Instruments and NXP , Nexperia former Philips .
I like TI , not just because my favorite American lives nearby ( A.J. from Austin , you know him ) , and I liked to watch "Dallas" haha ! But TI has a big offering of all the logic families , nice website (but slow with many little mistakes on it and for some reason I can't get links to the application notes ) and the cost saving TI store. TI also still uses the "old" beautiful and logical symbols for gates not the BS "newer" ones that NXP uses. So my hat off for TI.
Now Philips , oops Nexperia , have the better IC's . Since the 80's , Philips came out with the superior LOCMOS process , not a marketing gimmick . I tested a lot of logic IC's from different manufacturers back then, Toshiba , ST , Fairchild , RCA, NS ,.. Philips was nearly always the winner in speed ( higher frequencies) and consumption at same the freq's. Back in those days I did not look at Cpd's , I didn't always have a databook and there were no pdf's to download. I just bought and tested them , easier in PDIL in DIP sockets.
Cpd's !! Although the newest families have Cpd's that are nearly the same for different gates , different manufacturers , the older families differ a lot ! From the newest like , yes HCS and AUP , it seems it's a copy and paste , I still have to verify that with my own tests whether it is like the datasheets say it.
Nexperia is nearly always the better part compaired to TI (and others) : lower Cpd, higher freq , lower propagation delay times.
Nexperia's website is fast but slightly less appealing and less infomative . Nexperia's weakest point is its "store". Prices are identical to Mouser prices (for all I have looked up) , and both have the same covid banner of a 2 day delay because of covid. I mailed them about it but no reply. Pretty safe to say Nexperia's store is bogus , it's a Mouser front , with the same elevated prices . So no savings there like TI's store.
So there you have it : Cheaper but lower performance (for some ) TI Logic IC's at the TI online store OR high priced , higher performance Nex IC's , better directly from Mouser so you can order other items too like R 's and Cap's,...
Rarely Mouser can be cheaper like 74HC85 : TI store 0,746 $, Nxp at Mouser 0,417$ ...Luckily for me I can buy Philips (so older) 74HC85 for 0,220 $ locally tax incl but only in tssop.
Yes Cpd again , why hammer on it while we as DIYaudio will nearly always use low freq or pretty much static ? Because we want the best . There is the Ic quiescent current , 1 to 20 uA of CMOS, there is the peak current at the switching threshold , important with slow input voltages , ST are much better here , and there is the quiescent current when inputs are closer to the thresholds , these are important when level shifting , and there is Cpd , a measure for how much an IC is drawing at a certain frequency : I = Hz x Cpd x Vcc . So a gate with a Cpd of 20pF at 10 Mhz at 5V Vcc with nothing on its output should consume 20pF x 10Mhz x 5 V = 1 mA . Why is this important ? You will see that a gate has a Cpd of 25 pF , lets say a TI 74LVC1G02 and an Nxp 74AUP1G02 only 4,1 pF for direct comparison , the AUP will need about 5 times less current for about the same freq . Of course the Nxp AUP will cost 4 times as much at Mouser against the TI LVC direct from the TI store.
These differences are there too with ordinary ones like : Older XOR TI 74HC86 36 pF , 74HCS86 10pF or TI 74HC74 35pF ! TI 74AHC74 32pF !! > Nxp 74AHC74 12pF , TI 74HCS74 10 pF (if that is not a copy and paste). You really have to wonder about these numbers , and verify . So many more with big differences.
What manufacturers don't specify is how they measure Cpd , and that could be why Nexperia has better numbers . Somewhere on one of the sites it say that Cpd's are calculated by the design , not by actually measuring consumption at a frequency.
Now if it says 10 pF for a gate like a NAND , does this mean with both inputs (of a dual input NAND) used to "inject" the signal , or just the one input while the other is on the Vcc + ( for a NAND) ? There is a difference . Even when you block the gate , putting one input on the 0V gnd so the output is always a 1 ( for a NAND) , and putting a signal on the other input , the device will draw a current because those input Fets are switching even while the output isn't. ( a LVC32 on 3,3V with 10 MHz on 1 input and the other on Vcc , still draws 140uA ).
Another example : D-flipflops : A clock signal with D input not changing ? Or make it toggle with D connected to -Q , but this means that the -Q output is driving a 3-6 pF input , so how is the Cpd related in that scenario ?
For me there are only the two big ones : TI , Texas Instruments and NXP , Nexperia former Philips .
I like TI , not just because my favorite American lives nearby ( A.J. from Austin , you know him ) , and I liked to watch "Dallas" haha !
But TI has a big offering of all the logic families , nice website (but slow with many little mistakes on it and for some reason I can't get links to the application notes ) and the cost saving TI store. TI also still uses the "old" beautiful and logical symbols for gates not the BS "newer" ones that NXP uses. So my hat off for TI.Now Philips , oops Nexperia , have the better IC's . Since the 80's , Philips came out with the superior LOCMOS process , not a marketing gimmick . I tested a lot of logic IC's from different manufacturers back then, Toshiba , ST , Fairchild , RCA, NS ,.. Philips was nearly always the winner in speed ( higher frequencies) and consumption at same the freq's. Back in those days I did not look at Cpd's , I didn't always have a databook and there were no pdf's to download. I just bought and tested them , easier in PDIL in DIP sockets.
Cpd's !! Although the newest families have Cpd's that are nearly the same for different gates , different manufacturers , the older families differ a lot ! From the newest like , yes HCS and AUP , it seems it's a copy and paste , I still have to verify that with my own tests whether it is like the datasheets say it.
Nexperia is nearly always the better part compaired to TI (and others) : lower Cpd, higher freq , lower propagation delay times.
Nexperia's website is fast but slightly less appealing and less infomative . Nexperia's weakest point is its "store". Prices are identical to Mouser prices (for all I have looked up) , and both have the same covid banner of a 2 day delay because of covid. I mailed them about it but no reply. Pretty safe to say Nexperia's store is bogus , it's a Mouser front , with the same elevated prices .
So no savings there like TI's store.So there you have it : Cheaper but lower performance (for some ) TI Logic IC's at the TI online store OR high priced , higher performance Nex IC's , better directly from Mouser so you can order other items too like R 's and Cap's,...
Rarely Mouser can be cheaper like 74HC85 : TI store 0,746 $
, Nxp at Mouser 0,417$ ...Luckily for me I can buy Philips (so older) 74HC85 for 0,220 $ locally tax incl but only in tssop.Yes Cpd again , why hammer on it while we as DIYaudio will nearly always use low freq or pretty much static ? Because we want the best . There is the Ic quiescent current , 1 to 20 uA of CMOS, there is the peak current at the switching threshold , important with slow input voltages , ST are much better here , and there is the quiescent current when inputs are closer to the thresholds , these are important when level shifting , and there is Cpd , a measure for how much an IC is drawing at a certain frequency : I = Hz x Cpd x Vcc . So a gate with a Cpd of 20pF at 10 Mhz at 5V Vcc with nothing on its output should consume 20pF x 10Mhz x 5 V = 1 mA . Why is this important ? You will see that a gate has a Cpd of 25 pF , lets say a TI 74LVC1G02 and an Nxp 74AUP1G02 only 4,1 pF for direct comparison , the AUP will need about 5 times less current for about the same freq . Of course the Nxp AUP will cost 4 times as much at Mouser against the TI LVC direct from the TI store.
These differences are there too with ordinary ones like : Older XOR TI 74HC86 36 pF , 74HCS86 10pF or TI 74HC74 35pF ! TI 74AHC74 32pF !! > Nxp 74AHC74 12pF , TI 74HCS74 10 pF (if that is not a copy and paste). You really have to wonder about these numbers , and verify . So many more with big differences.
What manufacturers don't specify is how they measure Cpd , and that could be why Nexperia has better numbers . Somewhere on one of the sites it say that Cpd's are calculated by the design , not by actually measuring consumption at a frequency.
Now if it says 10 pF for a gate like a NAND , does this mean with both inputs (of a dual input NAND) used to "inject" the signal , or just the one input while the other is on the Vcc + ( for a NAND) ? There is a difference . Even when you block the gate , putting one input on the 0V gnd so the output is always a 1 ( for a NAND) , and putting a signal on the other input , the device will draw a current because those input Fets are switching even while the output isn't. ( a LVC32 on 3,3V with 10 MHz on 1 input and the other on Vcc , still draws 140uA ).
Another example : D-flipflops : A clock signal with D input not changing ? Or make it toggle with D connected to -Q , but this means that the -Q output is driving a 3-6 pF input , so how is the Cpd related in that scenario ?
So which families are interesting ?
Of course the reason of this thread is 74HSC , excl from TI . You'd think that being the only one they would be high priced , but they are usually the cheapest !
So 2 to 6 V but with diode to Vcc like HCmos , no power down voltage on input or Hi > Lo level translator . Faster than HC , all ST inputs , much lower Cpd than HC , if this is right because it is hard to believe all gates and some D-ff all have exactly 10 pF...
Overall a winner.
Negative : Only gates , some D-ff , buffers , decoders . Nowhere near the amount of functions as HC. No 1G or 2G's as in the little logic series.
BTW : TI is funny listing HSC04 and HCS14 : they are identical , another copy and paste pdf.
AHC : next gen HC 2 to 5,5 V , well they were already there in the 90's ....
3 x as fast , usually somewhat better Cpd than HC. Inputs higher than Vcc allowed: they have found a way to protect inputs against ESD without using diodes to the +Vcc , so level translator from high to low is possible. Has some 1G and 2G .
ST of 200mV is standard , but this hasn't much real use for me , you need the real bigger ST of >500mV , like AHC14 , AHC132 and 1G17. Still usable on 5 V. Like HC and HCS 4- 8 mA output.
Negative : only the usual gates , D-ff , decoders .
74LVC ! Also an older family.
Fast ! 24 mA output with reasonable ground bounce.
1,65 V to 3,6 V for regular IC's , 5,5 V for 1G , 2G , not sure why , higher voltages than Vcc on inputs like AHC. Nexperia starts at 1,2 V .... again Nex is superior .
Should have a little 150 mV ST , but again for the real ST : LVC14 , 1G17 and 132.
Negative : TTL level inputs although at 3,3 V and less ,but at these voltages it doesn't matter that much.
Cpd is high but still low for an 24 mA output and some HC is even higher .
Often big differences in Cpd between NXP and TI . Still have to wonder how TI and Nex calculate Cpd's ...
Slow inputs even with the real ST will draw peak currents of 16 mA , which makes them not good for slow inputs voltages. So what I said about 74LVC1G17's in post #11 is a bit wrong unless you don't mind 16mA peaks for an RC on the 1G17's input with 5V Vcc. (up to 40 mA peaks on regular LVC thresholds 3,6Vcc)
And there is 74AUP !
Ultra low power CMOS !! Music to my ears , I should love these the most.
TI and NXP have about the same Cpd , a very low 4 to 4,5 pF , again I'm wondering is this a copy and paste . Has the technology evolved so much that there is minimal difference in Cpd and Propagation delay between different gates , functions and manufacturers ?
Inputs can take voltages above Vcc but no more than 3,3 V , these are fast too , close to LVC but with barely any groundbounce/ringging.
SchmittTrigger : 1G14, 1G17 and NXP 1G132 . Not many logic functions but they do have the configurables 1G57-58-97-98 , these are also in LVC and have 3 real ST inputs.
It can't be all good right ?
Indeed , the negatives : AUP only comes in 1G and 2G little logic.
No 4 gates or 6 inverters in 1 package . It's the smallest family of the lot , and the price is usually the highest . AUP only 3,6 V max , but 0,8 V minimum so ok on 1 NiMH battery . Output is more like the 4000 series : not much current , not really a problem.
I'm definitely going to try these , although 3,3V or lower is not ideal.
If you're going to drive a LED , blue , white and some green need 2,5 to over 3 V , that doen't leave much room. Also driving a mosfet gate at 3,3 V and lower will not get you the best Rdson . There are mosfets that have lower threshold , so powering from 2 V and lower will work but again not optimal for Rdson. Of course bipo's go from 0,6 V , but who still uses bipo's for switching ? Opto's only need about 1 V , so they are ok with logic on low voltages. But nice and fast and low current for on 1 Li battery or the regular 1,2 to 1,5 V NiMH and alkalines.
Other families don't interest me : AUC , AUP is better.
ALVC , LV , ...
Of course the reason of this thread is 74HSC , excl from TI . You'd think that being the only one they would be high priced , but they are usually the cheapest !
So 2 to 6 V but with diode to Vcc like HCmos , no power down voltage on input or Hi > Lo level translator . Faster than HC , all ST inputs , much lower Cpd than HC , if this is right because it is hard to believe all gates and some D-ff all have exactly 10 pF...
Overall a winner.
Negative : Only gates , some D-ff , buffers , decoders . Nowhere near the amount of functions as HC. No 1G or 2G's as in the little logic series.
BTW : TI is funny listing HSC04 and HCS14 : they are identical , another copy and paste pdf.
AHC : next gen HC 2 to 5,5 V , well they were already there in the 90's ....
3 x as fast , usually somewhat better Cpd than HC. Inputs higher than Vcc allowed: they have found a way to protect inputs against ESD without using diodes to the +Vcc , so level translator from high to low is possible. Has some 1G and 2G .
ST of 200mV is standard , but this hasn't much real use for me , you need the real bigger ST of >500mV , like AHC14 , AHC132 and 1G17. Still usable on 5 V. Like HC and HCS 4- 8 mA output.
Negative : only the usual gates , D-ff , decoders .
74LVC ! Also an older family.
Fast ! 24 mA output with reasonable ground bounce.
1,65 V to 3,6 V for regular IC's , 5,5 V for 1G , 2G , not sure why , higher voltages than Vcc on inputs like AHC. Nexperia starts at 1,2 V .... again Nex is superior .
Should have a little 150 mV ST , but again for the real ST : LVC14 , 1G17 and 132.
Negative : TTL level inputs although at 3,3 V and less ,but at these voltages it doesn't matter that much.
Cpd is high but still low for an 24 mA output and some HC is even higher .
Often big differences in Cpd between NXP and TI . Still have to wonder how TI and Nex calculate Cpd's ...
Slow inputs even with the real ST will draw peak currents of 16 mA , which makes them not good for slow inputs voltages. So what I said about 74LVC1G17's in post #11 is a bit wrong unless you don't mind 16mA peaks for an RC on the 1G17's input with 5V Vcc. (up to 40 mA peaks on regular LVC thresholds 3,6Vcc)
And there is 74AUP !
Ultra low power CMOS !! Music to my ears , I should love these the most.
TI and NXP have about the same Cpd , a very low 4 to 4,5 pF , again I'm wondering is this a copy and paste . Has the technology evolved so much that there is minimal difference in Cpd and Propagation delay between different gates , functions and manufacturers ?
Inputs can take voltages above Vcc but no more than 3,3 V , these are fast too , close to LVC but with barely any groundbounce/ringging.
SchmittTrigger : 1G14, 1G17 and NXP 1G132 . Not many logic functions but they do have the configurables 1G57-58-97-98 , these are also in LVC and have 3 real ST inputs.
It can't be all good right ?
Indeed , the negatives : AUP only comes in 1G and 2G little logic.
No 4 gates or 6 inverters in 1 package . It's the smallest family of the lot , and the price is usually the highest . AUP only 3,6 V max , but 0,8 V minimum so ok on 1 NiMH battery . Output is more like the 4000 series : not much current , not really a problem.
I'm definitely going to try these , although 3,3V or lower is not ideal.
If you're going to drive a LED , blue , white and some green need 2,5 to over 3 V , that doen't leave much room. Also driving a mosfet gate at 3,3 V and lower will not get you the best Rdson . There are mosfets that have lower threshold , so powering from 2 V and lower will work but again not optimal for Rdson. Of course bipo's go from 0,6 V , but who still uses bipo's for switching ? Opto's only need about 1 V , so they are ok with logic on low voltages. But nice and fast and low current for on 1 Li battery or the regular 1,2 to 1,5 V NiMH and alkalines.
Other families don't interest me : AUC , AUP is better.
ALVC , LV , ...
About level translating :
You'd think making an oscillator (like a high freq X-tal ) on a low voltage to save power and then with one of the gates or buffers go to a higher voltage , but those will have an input signal that peaks to much near its threshold level that it actually consumes more power than having the oscillator work on the higher voltage.
I've tested this and it is true .
Going from high to low voltage supply is not a problem when the logic input permits it.
Why all this ?
For selecting what to buy , you need to be sure the information on datasheets true.
So I been doing some tests. I build a 32kHz and 10 MHz Xtal oscillator with the old but still good 4069UB and a 20MHz one with a 74LVC00 (yes not an UB and it works) and bought a 125MHz oscillator all in one .
So what do the datasheets say ? LVC00 TI Cpd :19pF (NXP 11,8pF), LVC02 TI 9,5pF (NXP 8,5), LVC32 TI 12,5pF (NXP 11 pF) and LVC10 TI 11pF (NXP 8,8). I do not have the NXP.
I do have the TI's and tested them in the 5 Mhz to 31Mhz range (the 62,5 Mhz and 125MHz are less accurate measurements, the way you hold and connect the wire to the input distorts the signal , the up and down slopes have a influence on consumpion). The LVC00 's 19pF is is about right , LVC02's 9,5pF is no way , it draws just above the LVC00 , LVC32's 12,5pF consumes even more , LVC10's 11pF , again more than the 00 and between the 02 and 32.
So the LVC's 19pF is about right but the other 3 consume more , much more than their bogus Cpd numbers suggest .
How to trust the uniform 10 pF for all HCS gates ? Something isn't right here.
TI's 74HC74 : 35pF !! (nxp 24pF) I measured slightly lower as a toggle flipflop (2 divider) but theoretically it should be higher because the output is connected to at least 3 pF D input at half the freqency.
TI's LVC74 26pF (nxp 19,1pF) , measures about right but TI's LVC1G74 is 37 (at 3,3V) ... what ? Why the difference between 26 and 37 ? Makes no sence. Nxp's LVC1G74 is .. wait for it ... 15pF , not exactly the 19,1 but what a difference with TI's 26-37 ! Who's BS'ting here or is Nexperia really this much better ?
TI claims 74HCS74 is also 10pF , that's 3 x less than their HC74 ! And the same as a simple gate ? Nxp's 74AHC74 is 12 pF and only has ST on their CLK.
Both have AUP1G74 but more expensive and only in an extra small package VSSOP , too small for me. 5,5 pF and 3,9 for nxp.
You'd think making an oscillator (like a high freq X-tal ) on a low voltage to save power and then with one of the gates or buffers go to a higher voltage , but those will have an input signal that peaks to much near its threshold level that it actually consumes more power than having the oscillator work on the higher voltage.
I've tested this and it is true .
Going from high to low voltage supply is not a problem when the logic input permits it.
Why all this ?
For selecting what to buy , you need to be sure the information on datasheets true.
So I been doing some tests. I build a 32kHz and 10 MHz Xtal oscillator with the old but still good 4069UB and a 20MHz one with a 74LVC00 (yes not an UB and it works) and bought a 125MHz oscillator all in one .
So what do the datasheets say ? LVC00 TI Cpd :19pF (NXP 11,8pF), LVC02 TI 9,5pF (NXP 8,5), LVC32 TI 12,5pF (NXP 11 pF) and LVC10 TI 11pF (NXP 8,8). I do not have the NXP.
I do have the TI's and tested them in the 5 Mhz to 31Mhz range (the 62,5 Mhz and 125MHz are less accurate measurements, the way you hold and connect the wire to the input distorts the signal , the up and down slopes have a influence on consumpion). The LVC00 's 19pF is is about right , LVC02's 9,5pF is no way , it draws just above the LVC00 , LVC32's 12,5pF consumes even more , LVC10's 11pF , again more than the 00 and between the 02 and 32.
So the LVC's 19pF is about right but the other 3 consume more , much more than their bogus Cpd numbers suggest .
How to trust the uniform 10 pF for all HCS gates ? Something isn't right here.
TI's 74HC74 : 35pF !! (nxp 24pF) I measured slightly lower as a toggle flipflop (2 divider) but theoretically it should be higher because the output is connected to at least 3 pF D input at half the freqency.
TI's LVC74 26pF (nxp 19,1pF) , measures about right but TI's LVC1G74 is 37 (at 3,3V) ... what ? Why the difference between 26 and 37 ? Makes no sence. Nxp's LVC1G74 is .. wait for it ... 15pF , not exactly the 19,1 but what a difference with TI's 26-37 ! Who's BS'ting here or is Nexperia really this much better ?
TI claims 74HCS74 is also 10pF , that's 3 x less than their HC74 ! And the same as a simple gate ? Nxp's 74AHC74 is 12 pF and only has ST on their CLK.
Both have AUP1G74 but more expensive and only in an extra small package VSSOP , too small for me. 5,5 pF and 3,9 for nxp.
Why do I write all this ?
Because the inconsistencies are frustrating.
While there is often so much difference between same types of logic of the same family and between the usual and the 1G, 2G 's and of course between manufacturers , we are now asked to believe nearly all HCS have exactly 10pF Cpd , AUP's around 4-4,5 , but others vary from more than a little to way too much .
How to choose ? I could buy a ST NAND like 74HCS00 with the not trusted 10 pF Cpd , or NXP's faster 74AHC132 with Cpd 11pF but at Mouser so double the price of the HCS.
For HCS10 , 11 , 20 , 21 and 30 , even HCS4075, HCS has no competition if you want ST inputs , even if you don't , the others have bad Cpd and propagation delays.
If you don't buy at TI's store and don't really want the all ST inputs , NXP is nearly always the better choice.
Because the inconsistencies are frustrating.
While there is often so much difference between same types of logic of the same family and between the usual and the 1G, 2G 's and of course between manufacturers , we are now asked to believe nearly all HCS have exactly 10pF Cpd , AUP's around 4-4,5 , but others vary from more than a little to way too much .
How to choose ? I could buy a ST NAND like 74HCS00 with the not trusted 10 pF Cpd , or NXP's faster 74AHC132 with Cpd 11pF but at Mouser so double the price of the HCS.
For HCS10 , 11 , 20 , 21 and 30 , even HCS4075, HCS has no competition if you want ST inputs , even if you don't , the others have bad Cpd and propagation delays.
If you don't buy at TI's store and don't really want the all ST inputs , NXP is nearly always the better choice.