Hi. We're going to take a look at Digital Logic data sheets today. We're going to start out with your classic 7400 series logic. in this case, these seven 4hc Double-o which is a quadrant two input NAND gate.

We're going to go through the data sheets step by step and we're going to take a look at what all this stuff here means and we're going to go down into the specs and look at all of what this stuff means. Now we're going to take a look at the Texas Instruments datasheet here and different data sheets will be are slightly different in various ways. You might to take a look at some others for the same day, but you don't Sheet start out very typical. They've got the features here.

the top-level features. Now what are the golden rules of reading data sheets is to not take the banner headline specs here at face value because they could actually not just be wrong but not wrong, but misleading so they don't tell a full story. You really have to go down to the main specifications further on in the datasheet. Look at all the little asterisk sirs and the little numbers and everything else to really get a feel for it.

but at a general level it's not too mad. You know it can tell you the typical operating voltage from 2 volts to 6 volts. for example, the typical hour propagation delay which is T P D there the output drive capability, but there's a trap in that one which we'll take a look at potentially and classic applications here in data sheets. These are engineers typically get a little bit of a laugh out of these things.

They're really, they're just for a marketing warm fuzzy. It's like oh, I'm developing an enterprise tablet. So oh look at that. It just so happens that this is the perfect part.

for that. It's like, you know, like it. It's just ridiculous. I'm developing a PDA Wow It says that this is fantastic.

No, it'd be just getting a little giggle out of those anyway, and often you'll find on the front page. Here you'll find what packages they're available in. In this case, they're available in your pay Tip which is plastic dual inline package that's the one you used to that plugs into your breadboard and then it has the Associated part number here with it. so you've got to have the N on the end.

You'll notice that the numbers make a difference and if you add the NS on the end here, then it's the Esso package. So that's the surface mount package so it's very different. So when you go to order these parts, just be careful that you do get exactly the right number from Digi-key or Mouse or whoever you're actually buying these drums. Otherwise you'll come a gutter and order the wrong package.

So we're looking at the Heights M4 HC Low which contains four independent two input gates. There they perform the boolean function and we've gone through sorry NAND we've gone through that in a previous video now. I've got our table of contents. Nothing fancy here.

Look out for the revision history by the way of these, because often they might change some important stuff from Revision E to F. What have they added? They've changed the SD They've added the SDR ratings table how they yes, maybe the old datasheet didn't have that. For example, I added a military disclaimer and things like. But there can often be really important changes, especially in complex modern devices like our microcontrollers for example, can have really important differences in the revision history.

They can have all sorts of silicon bugs. and then we've got our typical our pin outs. here. these are for pretty much all of the packages.

So for the SS AP the SOI sea surface mount ones for the dip plastic dip the ceramic dip packages are. by the way, we didn't show up the top here that the five for hey see, this is the military. Our version the 5400 series and that has a ceramic dip package version. It's just a more robust version.

you know then your regular plastic dip package here because the military like this ceramic dip. So anyway, let's not get mixed up in that. So you've got your typical pin outs. Um, you've got your pin at one identifier up here.

And unless they say well, yes they do say here top view and top view So looking down from the top of the chip don't make the mistake of getting that back to front like you often do on these are like surface mount leadless chip carriers. You might think oh, these pins because they're hidden on the bottom of the chip here like this. Then I've got to flip the chip over in order to look at the pins and see which is pin 1. This is top view, so don't fall for that one.

And there's the pin 1 identify which you'll typically be a silk-screened or laser marked circle on top of the package, but not all packages will have that. You've often got to go right down to the bottom of the datasheet, which will take a look at later to get the physical identifier. Then you can have a look at the pin functions here. The pin function table as it's called is often a very handy.

It just gives you a an overview of what the actual pin is like. This is the gate 3 input for example by gate and we're not talking about a MOSFET I gate. For example, we're talking about a logic gate. So we're talking about one of the Nan's Remember this contains four different NAND gates and they're actually numbered this one.

This first number down here like this: so 1, 2, 3, and 4. So input A So this is gate number One, Input A Gate number 1, Input B and gate number 1 output Y and then on your larger packages here, there's a bunch of NC's or not connected and it tells you that there's no internal connection there. And of course, ground is Grampian and VCC is your positive power pin if you didn't know what VCC means and well, where that actual term comes from, we won't get into. but you look in your functional description table, it's the power pin.

Thank you very much. Now here comes probably one of the most important ones here. The absolute maximum ratings now do not exceed these under almost any circumstances. Ok, it because you will basically ruin your device.

It'll blow up the magic smoke escape whenever. Okay, so let's take a look at our supply voltage VCC here. a minimum of not 0.5 because it's a reverse diode protected. Anyway, we won't go there.

It's got a maximum of 7 volts so do not exceed 7 volts. But you might remember from way back up the top. Here it said wide operating voltage range of 2 to 6 volts and that is the operating voltage range. This is the absolute maximum specs.

Just because it's on there doesn't mean you can operate this chip at 7 volts. No, that's just where you won't do major damage. Ok, let's have a look at this input clamp current here and it's plus minus 20 milliamps like this. Now if you have a look at the conditions under which it's valid, the VI which is input is less than 0 or VI is greater than VCC.

That means the input is less than is less than this supply rail or greater than the supply rail. And that's important because inside the let's have a look, what's inside the this datasheet actually doesn't have it. otherwise. I'd Show you the diagram.

But basically this is the VCC pin. This is the input pin like this. Ok, so that's our input pin and then that buggers Off to our internal secretary. They've got these I internal clamp diodes here and that's what they're talking about.

the clamping the current. So when this input here goes, say plus, you know 6 volts or whatever that's bigger than VCC up here which might be 5 volts. So therefore, current is going to conduct through the diode here and that's what they're saying. You want an absolute maximum there of absolute maximum of plus minus 20 million.

So anything over 20 milliamps and your risk actually blowing your input clamp diodes so don't exceed that. So how do you avoid exceeding that? Well, either raised my little diagram here, but you impair. If you know it's going to clamp, you have an input limit currently. resistor like that so depends on the maximum voltage V max here that you have on the input, You choose that resistor value to limit the absolute current through that clamping diet to plus minus 20 milliamps.

If you're looking to protect your device from overloads via this clamping mechanism which you might if it's hooked up to any sort of like external circuit, for example, Next up, we've got continuous output current here. or IO O stands for output. Of course, it's plus Minus 25 milliamps. So if you've got your NAND gate like this and you're powering this from say, a 2.5 volt rail to make it nice, then you basically don't want your load to exceed a hundred ohms.

If you do, then that's going to exceed the maximum value here of plus minus 25 milliamps. the continuous output current, so the instantaneous could be higher, but they're not going to tell you that it's the continuous output current. So anything lower than a hundred ohms, you've exceeded your absolute maximum ratings and what the magic smoke could escape, don't do that, so you might think AHA plus minus 25 milli answer sounds pretty crunchy. I've got four of these gates.

Therefore, I can have a maximum of a hundred four times, twenty-five or a hundred milliamps coming out of this chip. Whoa, No, you can't look at the continuous current through VCC or ground is only plus minus 50 milliamps here. so you can only take a maximum of plus minus 50 milliamps continuous from the actual chip. So if you've got your chip like this and then share five on rail or whatever it is, and you've got your four outputs here.

The total current on all these four outputs is not to exceed 50 milliamps. Even though you've got that wonderful plus minus twenty five millionths there for each output, the total is not to exceed 50. Otherwise, you'll just blow up something in Colonel. They'll also tell you what ESD rate in this chip is for because these most modern ships have ESD protection on the inputs and they can survive the human body model.

That's a spirit. We won't go into details, but basically Plus/minus 2,000 volts can clamp the input, no problems whatsoever. It can survive that electrostatic discharge. But as always, if you're really looking to protect your devices from external static shock, then you might have an external static clamp that can dissipate more energy than this particular chip can.

But still, it does have ESD protection built in. Now up here, we saw our absolute maximum reigns. As I said, You are not to use these as a design. You know specification.

You are not to design for those. they're just absolute no. You're gonna break the damn thing if you go down here. What? Here it is: Recommended Operating Conditions: This is the one you want to design around.

So you saw I saw before how we had a maximum supply rail. Seven volts. They're not do not operate at seven volts. It's actually six volts is the safe recommended operating condition for this chip, so don't exceed six volts Now of course, will have a minimum operating volts and voltage here of two volts.

And of course, you can go under that if you want, and you're almost certainly not going to damage your chip, but it's not guaranteed to work. The logic in there is just not going to function properly unless you've got that 2 volts minimum. now. A very important parameter is VI H and VI L.

You'll see this for all sorts of digital logic. It's you know, it's universal across the board and V stands for voltage of course, And then I H is not IH it's I and then H. So I means input just like a woman output and H means high and early means low in the digital logic scheme. So VI H ere is voltage input high.

So the high level input voltage it tells you they're fantastic. Now, this is actually split into three different specifications here for three different values of your supply voltage, for example. So the value is they actually going to change with the supply voltage? It's a ratio metric as it's called, so unfortunately, if you operate at the normal 5 volts, well, it's sits somewhere in there slightly above that. so they actually don't give you it for the nominal 5 volt figure.

So you've got to go. Yeah, it's somewhere between three point one, five volts and four point two volts. Now what VIH actually is? Let's have a look at this. We've got our NAND gate here.

Okay, let's have a look. We've got our two inputs here, so we've got our threshold. We're going to a five volt power supply up here and our zero volt ground. Okay, so we're looking at the input pin here.

So what VIH is is going to be a level up here somewhere. So let's say we'll work in VCC 4.5 volts up here. Okay, three point One, five volts and minimum. So if we have a look down here, this is actually going to be three point one, five volts and then our low level threshold V Il here.

Once again, at four point, five volts is going to be one point three five volts maximum. So it's going to be one point three Five volts. So this is the threshold level of our digital logic. So if our input signal goes up like this, let's say it shoots up like that and comes back down.

Oops. It never got to a point where it actually reached this threshold here. So let's say we had an input which goes just like that for a split second. then our input here is actually going to register as a logic high and one.

And likewise, if our signal just went down like that, as long as it goes through that threshold level there, it is recognized as a logic low. But if the signal is inside this dead band here, then well, it's undefined basically. and you don't know what the digital logic gates going to do it. You can't be guaranteed at all, but you have to actually be careful with these because look, these are max and minimum values, so this is what they guarantee.

But you'll notice that they don't give a nominal figure in here for these, so you know you just have to design design around the men and the mace. Sometimes they'll give a nominal, sometimes they won't depending on the specification. but that's these figures are what they absolutely guarantee at that voltage and over the operating free air temperature range. So that's over the full operating temperature range of this thing, which is down here for the regular seven for hate seen on military stuff, it's minus 40 to plus eighty five degrees Celsius Or you typical, our commercial temperature operating range in military ones is 7400 series.

Just basically they're the same, but they're rated for a much higher temperature range. Now let's have a look at the DT DV or delta T versus Delta V and that sounds complicated. but look at the label here. it's the input transition, rise and four time.

So basically if we're looking at our input signal, it's how fast our input signal revs up like this. So let's actually have a squiz here. Okay, this is our let's say this is our input and it ramps up like that. Okay, so you're going to have a time there between there and there and that might be say one millisecond to get from 0 up to VCC Or it's actually in this particular case.

it's the transition time between these threshold voltages here. Essentially, because that's what we really care about. We care about how much time the signal is actually spending in time inside this dead zone here. Now in this case of 1 milli second here.

but why we're gonna fail? Look at the specs here. There are thousand nanoseconds at 2 volts. Or it's A at 5 volts. There, it's going to be.

You know, well just call at 500 nanoseconds. for example. that is the maximum because we're talking about maximum here transition time. So it has to be faster than that.

It's got a ramp up. at least in that 500 nanoseconds for a 5 volt rail. for example. If it doesn't, then the gate is not guaranteed to work.

It could go metastable. It could do anything. Am I talked about meta stability in a previous video? It's just not guaranteed to work at all. So you don't want slow rising inputs.

That's what's Schmitt Trigger gates are good for. These are not Schmitt trigger gates. so you need to have fast transition rise and four times on your input. For this particular type of a CMOS logic or pretty much any CMOS logic will have a maximum transition rise in full time unless it's a specific Schmitt trigger time.

Next up, pretty much any device will have thermal information or the thermal resistance of the package. Now because these aren't power devices, they're just simple logic gates. They're not designed for power dissipation, but if they were, it's still or relevant. I Won't go into the various details I've done a comprehensive video on our thermal information that I can link in at the end of this.

but basically it's the Junction to ambient thermal resistance here which matters. Or let's say you wanted to put a heatsink on top of this one. you'd be looking at Junction which is the semiconductor Junction inside the thing to the case, the top of the case where you want to put your heat sink on to. So if you had a plastic dip package, here's the value is 45 degrees C per watt.

So if your chip was dissipate in 1 watt of power, then it would increase that. There would be a temperature differential between the internal Junction and the top of the case of 45 degrees. So let's just say the top of your chip happened to be measuring of 45 degrees Celsius Well that's not what the temperature of your silicon die inside is that it's at 45 degrees plus 45 point one or ninety point one degrees Celsius inside chip due to that very high thermal resistance. but we won't go into details that's more relevant for our power packages.

Okay, let's have a look at Vo a Chair Or the O stands for voltage o stands for output Hate stands for high. So the voltage output high. Now it's once again. it's got these at three different test conditions for three different output high currents when you're actually sourcing for milliamps, five point two, or a very low 20 micro amps as you would if you're just driving some other gates or something like that.

And then for each one of these currents, you get three different specifications for the different voltage supply values. Now let's take this example here of VCC equals well. VCC equals six volts here. Now you'll notice that tipping like minimum, it's going to output, not six volts.

It's going to output five point five for example, or nominally typical, say an M This could change with temperature, for example. So the typical value could be five point eight. So once again, if you're gonna, if you're gonna design, if you're serious about your design specifications and your margins, and you're building a probe that was going to Pluto, then you know you're really you'd be designing around these these minimum values. Here, you would have been designing around the typical ones.

You would go. Well, this is going to be my worst case. So I'm going to design around that. But typical design use, and where it doesn't, you know it's neither here nor there.

Then typical values are just fine. But what it shows is that our supply pin is six volts. But we're only getting five point eight volts output. So let's actually a draw our gate here.

Okay, So we've got our NAND gate. Now this is our six volt supply pin inside. Here we have ourselves a little transistor like this which is going to the output pin and then if we have a resistor which is then going down to ground. This here is duck is not zero ohms output.

Okay, it has a resistance and you can calculate that output resistance based on the drop there. So we get in a note: point two volt drop at five point two milliamps output current. So use Ohm's law : that's homework for you. use Ohm's law.

Yes, there's the temperature I told you about at ambient temperature I Forgot to mention that. So anyway, you can essentially work out the output resistance of the effective output resistance. In quote marks of the MOSFET inside, there is no I've drawn a J feed, but it's actually a MOSFET and the output resistance of that at various currents. and that's why the difference in this voltage here is going to get higher and higher the higher your output current gets up to that.

Maxima You remember where it said 25 milliamps before was our maximum. our current and output current on the pin. Well, you can imagine how far the output voltage is going to drop based on 25 million output current if you're driving the lead. For example, at 20 milliamps or even 10 milliamps, it's going to have significant voltage drop and that may not matter.

but if you're driving something else where the output level is actually going to be an issue, then, well, you could come a gutter and you've got to take all that into account. but normally it's You know it's not a problem, but that's all part of reading the datasheet. This is what it all means. and Vol here is exactly the same thing.

except we've got another transistor. Well, actually I'll show you we've got another transistor down in here like this, which goes down the ground and that would be if we had a resistor going up to VCC like that. and then we've got current flowing through like that. Once again, you've got a certain dynamic resistance there of your output driver MOSFET and that will be once again determined by these figures.

Here, it won't be zero, it'll be not 0.26 volts there. for example, at 25 degrees C And you might notice that the seven for hate see the military version actually is worse than the commercial one. What's going on there? Well, you saw before the operating temperature range. the seven for the military staff five for series of logic is designed for a much wider temperature range, so the specification is actually going to be worse.

For that, it it just comes with the territory. All right, let's look at III here. once again, I is current and the little I there is input. So the current on the input ie.

effectively the input. resistance. And once again, they give you a range over that's valid. They're basically saying just over the full operating voltage range.

They're once again at a typical ambient temperature, and once again, we have a typical value here. You'll see it's typical and you can use that. But once again, if you're doing worst case design analysis, you'd go with the maximum. Okay, and there's a hell of a difference.

Look at how many orders of magnitude difference there, right? Three orders of magnitude difference between your typical value and your maximum, so that's a hell of a lot of order. Alright, so our typical value plus minus point one nano amps? that's a hundred Pico And so obviously this is a CMOS gate, right? There's hardly any input current whatsoever You can, you know do simple Ohm's law to figure out what the effective input resistance is at that particular voltage, but it's basically bugger all. But once again, that's going to change with temperature. So if you're relying upon that for some super duper ultra whiz-bang low-power design, that could matter, watch out for it.

And you could come a guts are there because these typical values basically the the typical values here are not. They might even say in here in the datasheet I'll have to check, but the typical values are not actually parametrically tested at the factory. they're just typical ones. They might batch test them occasionally or something like that to make sure that they're still meeting those typical values.

But the the chip you bite, you can't go to them and saying Oh I've measured one nano amp at 25 degrees C They're gonna come back to you and say, well, tough titties, It's plus my designer and nano ants. That's all. We guarantee your problem, not else. And now we have our Icc, which is basically our power consumption of the device I Think it had that at the top level of our spec.

Didn't it a low input current, low power consumption? There it is 20 micro amps maximum. so let's have a look if that matches down here. I Haven't checked this yet. 20 micro amps will it? ICC 20 micro amps for a 7? 4 HC Yes, it does.

There you go, there's the maximum figure at VCC 6 volts. So they've done the fool. They've done the maximum voltage there so it doesn't matter. You'll notice how they've got different input conditions here.

It doesn't matter whether the inputs are at VCC or zero and and it's also at zero output current. Of course you can't be drawing in the output current because then that will contribute to the chip power consumption and the ICC pin. So this is with the output pins floating and of course this is a maximum value here. So there you go: 20 micro amps for those playing long home for 7 4 HC double Oh Fly halfway to the moon on 20 micro amps.

Jeez. Anyway, let's continue. but that 20 micro amps is actually over the full temperature range. At the ambient temperature range of 25 degrees, you'll notice that it's only 2.

so you know it's an order of magnitude better than the banner spec right up the top. So I've just took that banner spec. Yeah, that's worst-case over the temperature range, but you're not gonna. Generally you're not going to be using your product at minus 40 degrees, for example, will write up at plus 85.

So and generally the chip. the dye itself is not going to be an elevated temperature because you're not dissipating any power or anything like that. So you know, really like 2 micro amps. If you're designing a low-power widget, you know you might say 5 or something like that.

perhaps. Of course you can characterize it yourself, but they don't provide any further characteristic graphs on these things and they provide any typical figure as well. They only give you a maximum figure now see I See is for capacitance and I is for the input of course and from any over the full operational voltage range. And because it's capacitance, the units of Pico farad's or puffs.

if you want to sound like an industry veteran then typical value of about three puffs on the input. So if you're using, if you've got your gate, I'll just draw an inverter. but you know if you've got your driving, several gates like this, say and I think could be reasons why you're doing this, then you know system design. Just basic system design means you often they're driving more than one gate, then your total load.

C L Load on the output here is actually you know three of those typical capacitance and that could matter for your slew rate up here. Where was it? Here you go? That could be a big deal for your input transition rise in full times because you're driving a capacitive load, so just be aware of that. That can be a big deal and maximum fan-out was a big deal back in the day when they design computers with 74 series logic because you'd have one chip drive in 20, 30. no other chips and it was a big deal.

and capacitance of the input pins really mattered. But that's not the end of the story there with the capacitance. In fact, it's just the start of the story that Ci is effectively the static capacitance. But what we've got here is a much more complex thing called CPD And I could probably do a separate video on this.

and this is the dynamic power dissipation. They don't say its dynamic here, but it is the dynamic power dissipation, capacitance per gate. And even though they're talking in terms of power, capacitance, and power dissipation, the units are still in Pico Farad's Puff, so it's much higher. It's actually twenty.

Pico Farad's Once again, that's a typical figure. They don't actually specify a maximum figure for that, but that's for a switching device. So in a complex system, this one here important one and not just the static value here for an individual input. So anyway, I won't go into details there.

We don't have the time to do that here. But yeah, there are two different figures there for capacitance ones CI and ones Epd person a dynamic power dissipation. Now let's look at T PD or T is time. So our units are going to be seconds.

No, no seconds in this particular case. and P is stands for propagation. D is for delay. So this is the propagation delay time.

They give you exactly what it's for from a or B input to the Y output. So let's assume that your input just goes high like that. there is no rise time. Let's just say it's infinitely fast like that.

and then your output will help. The T PD is how long your output takes to change like that. So your time in there is your T PD or how long it takes the internal logic to propagate from the input through to the output. and there's a typical figure here.

You might work from that, but once again, if you're doing worst-case system design, maximum is where it's at. so you know you don't want to come a gut. So because you're your fight your design around these figures and then your computer works fine at 25 degrees. Celsius.

But when you're sticking in a box and it's working at 40 degrees or in the middle of winter it's working at you know, zero degrees, then you can completely come a gutter and your digital logic system just starts having a fit. Weird errors start happening and you're not sure why. It's because you aren't taking into account the propagation delay. So let's say this is your input here.

but there's also buggers off to another input over here. You know, Let's let's let's say you have another gate over here, it's connected and then the output of this one here is also connected down to here. The output here is only going to be valid after this propagation delayed. I'm here like this because like a journey, but during that time the output here is undetermined for example.

So you're just got to make sure you don't come. A guts are there in terms of your digital logic system design. and this can apply equally well to FPGAs. For example, PLC's complex System design.

It doesn't have to be discrete chips like this. You're going to get the same the same parameters like these four and you know in internal gates inside FPGAs and other devices like that. Next we'll look at TT here, which is the transition time. It doesn't tell you that in this particular datasheet.

this one's a bit cryptic here. Other ones might be better, might be more descriptive in that aspect. So what it is is how long it takes for your output to transition from low to high Like that and that's your time in no, no seconds. Once again, typical and maximum figures.

So this Ti datasheet actually doesn't give a huge amount of detail here because this could also be affected by the output capacitance. Doesn't say anything. Let's actually go over to a next period datasheet. Showery.

This is the once again as for the exact same chip. it's for the seven 4hc double-o and if we go down here, let's have a look at the exact same parameter. There it is. Yeah, this one actually tells you its transition time.

Take a look at that and this one actually has C Figure six and look, this one gets quite intricate. Look at this. TP HL there. What on earth is that? Well, T Time P Propagation H-hi Whoa.

So it's the propagation delay time when it transitions from high to low output. So that's a combinatorial parameter that includes the transition propagation delay time plus the output transition delay time. See, we didn't get that Nice little informative. Our waveform even going to more details on that.

Oh Measurement points given in Table Nine. Let's have a look at Table Nine, Thank you very much. Wow Look, it's all happening here. Table 9 Input once again.

Aha See, this one specifies a load capacitance. So when you are your test circuit, you'll notice that it actually has a load capacitance on there. When they actually measure these parameters, which they put in the datasheet up here and check this out, look at this: Wow CPD is used to determine the dynamic power dissipation. There you go.

This one has much more detailed I Think we got that in the TI datasheet and you know there's that. Like the formula is actually quite complex where all these things are taken into account to give you your dynamic power dissipation capacitance, you know, make a big difference. Oh, it just made an absolute fool out of myself didn't. I Here we go: Parameter measurement information: They've got it here.

Sorry. T I Shouldn't have doubted you. I Still got my TI Tt old data book which is like four inches thick anyway. So yeah, there you go.

There's the E per. I Think we've gone through all of the specs have we? Yes, we have in the datasheet. Fantastic. Still more to go though.

so we've got all that fancy pantsy stuff here once again, with a test capacitance of 50 puffs there note a seal and that includes the probe and fixture capacitance as well. Trap for young players if you're not taking your probe capacitance into account because they're going to be viewing waveforms on the scope and stuff like that. So you're got to take in door. You need a low capacity of our proud to be doing that or at least have it characterized and measured.

Anyway, we're getting way out of the bounds of what we need to talk about for the datasheet. So we're done with all the specs and there's add functional block diagram Whoopty-doo They're still updating this datasheet in 2016, which is pretty amazing. TTL is like 50 years old now. 7 for HC is not quite that old.

but it's you're really getting up there. And there's our functional truth table which we've done a previous video on that will match your true T should know your truth table, fear and gate. We should be able to derive it. and a typical application.

there's an SR flip-flop that's just a how do I know it's a flip-flop It's just the cross configuration like that and set and reset and your Q and not Q outputs. so that would be equivalent to an SR to a seven 400-series Our SR flip-flop you can build up with two NAND gates if you really want to. Then we just got some nice little lower warnings here. Thank you very much! T I Take care to avoid bus contention because it drives currents that would exceed maximum limits.

The high drive also creates fast edges into light loads. Routing and load conditions must be considered to prevent ringing and that's all to do with PCB layout, routing, and stuff like that. And here you go. They actually explicitly tell you what we talked about before.

Load currents must not exceed 25 millions per output and 50 milliamps total for the part and outputs must not be pulled above. VCC Thank you very much your little gate and we do have a parametric curve here. You don't often get parametric curves in just digital data sheets, but they've decided to do the transition time versus voltage here. so you'll notice that the higher up voltage you go once you reach 5 volts here.

it's pretty much a fixed 5 nanoseconds transition at time there, so it's just faster. The lower voltage. If you walking down at 2 volts off a single Queen cell for example, Cr2032 coin cell, then you're working in this region. Well, you're working in this region here which where you have much faster transition times but not that it's going to matter because if you're working off coin cell or you're going to be ultra low frequency anyway like working off a watch crystal.

so did I said it? Then they're gonna give you some handy recommendations on that bypass in in case you didn't know, I've done a whole tutorial on bypassing so run into the limit of what I can link in at the end of the video really. So they recommend your typical naught point one mic hundred N and recommend multiple R ones for each power pin commonly used in parallel et cetera et cetera. And then we've got some nice layout, guidelines, and unused inputs. Thank you very much! Ty unused inputs to VCC or ground like this and I actually told you this here which I maybe forgot to mention because if you're talking about you know pound package, power dissipation and stuff like that that's going to be dependent upon, We recommend I'll find it I'll find it I'll find it, don't you worry? haha.

All unused inputs of the device must be held at VCC or ground to ensure proper device operation. You know if you leave one gate floating like the inputs to one gate floating, it's not really going to affect the other gates. it could on a more complex chip for example. that's why they tell you.

but also the fact that these are CMOS devices. If you leave your input pin just flapping around in the breeze open like that, then you're going to potentially get interference on that pin and it's going to start switching. and then you're gonna get where is it your dynamic capacitance? power dissipation. See what? Come on.

CPD You're going to be dissipating power, pissing away power because you live, you're getting coupling on. switching especially they could be due to routing right next to it. It could easily couple a signal into that floating input pin which could cause the input to oscillate and oscillation equals more power dissipation. So do Not leave your inputs floating.

Tie them. Got it. Look at this. They even have a document implications of slow or floating CMOS inputs and one of those I don't even have to read the document I Can tell you will be that excess power dissipation so just don't do it anyway.

Related links Now we're getting into the community resources blah blah blah technical. They link directly to their sample page I Wonder if even get a sample for a seven for hate? See double? Oh, these days? probably. you know me. Anyway, now we get into the package option addendum and this is where you actually get the orderable part number over here.

So that was for the ceramic dip package. So if you're looking for your plastic dip package, where is it? Your pea dip over here? That's the one you want. Now let's actually have a look. There's actually two plastic dip packages here.

One's got in there and one's got Ne4. Let's have a look at the difference. Both are lead-free lead ball finish. Aha.

One of them has a different finish on the pins. There you go. so if that mattered like a different metal finish on the pin. So if that mattered to you for really rose compliance.

but they're both rose compliant so they both lead free. But if that mattered to you from a solder in perspective or anything like that, you know they're critical. If your once again if you designed the pro flying to Pluto you've got one shot at this. you know you're you're gonna have.

and a dedicated engineer in the group just looking at the solder in and the metallurgy and all that sort of stuff involved in this sort of thing so you know that could. So if you're purchasing Department ordered one instead of the other, that could ruin your space probe and it looks like we've got more corporate waffle about lifetime buys and things like that if we make it obsolete. Bla bla bla bla bla bla. Nothing else happening.

Oh ah, now now we get it off you package aficionados here we go. Here's the tape and real information. This matters When you're getting your device manufactured, your assembly house really want to know this. They want to know.

Well, okay, it's a standard Esso type package. they're probably not going to. You know they're just going to be able to handle it. But this is you.

Know this can be important for our specialized devices and you can have them pin One. It tells you exactly where the pin one orientation is inside the quadrant of the pocket. Like this, and it's important information. Your assembler needs to know this sort of stuff so you know manufacturers might be different.

One manufacturer might have pin one orientation on the tape completely different to another manufacturer. Don't take it for granted. and in this particular case, they're all in quadrant one here of your tape like that. But as I said, different manufacturers could be different and how comes in the box after you box the fishy and adios and there you go.

you know how much shelf space it takes up, but that could be important for a huge manufacturer. You know if you're Apple and you've got all these tapes and reels and components and stuff like that, all this stuff takes up shelf space when you've ordered, you know 20 million of these parts. Anyway, let's get on down here. and now we have our physical package requirements.

These are the men max. These are all your mechanical engineers are all getting a bit moist. Now about the package. and there's the leadless chip carrier.

So how that's designed. If you were doing a have you know designing a pad, you know that just went examinate, your pad, went around there like that, then this sort of draw. It matters, right? So let's go down here. there's our SI package.

Once again, if you're designing a pad that sits on your chip like that, you know it's a standard SI package. But hey, let's just assume that it's something weird. You don't have the footprint for your design in your footprint, then you know by all means you've got to design your own footprint for this and some packages like Altium for example. other packages might have it.

PCB Layout packages might have a IP C-- footprint wizard for example and you need all of the information contained in here. it'll It'll have like a common format and stuff like that. It'll ask you for all these particular you know, these particular widths here and last year for your package with you know, stuff like that. So if you've got an Esso Package wizard generator that generates a footprint automatically, you just need to know this information and you can get that from the datasheet.

Oh look at that Wow ceramic jewel flat pack for those military aficionados where you can even cut out your board like this. you can even have by I cut out in your PCB like that we're chip actually sits flat and as then sold it on top of the pads like that. Seen that in various tear downs over the years. Da look we get actual photos.

This is the ceramic dip. Nobody uses ceramic. Oh well. military still use ceramic dip.

There it is. Yep, ya know and recommended footprints. Now here's the thing. Some people are all for using the recommended footprints inside the data sheet for a particular chip.

People will take that as gospel. others will not. Nope. Never ever touch a footprint inside a data sheet.

Never use it. You'll come a guard, see your assembler will hate you. Use the recommended ones from your assembler or your an IPC standards aficionado. You only use footprints from the IPC I won't get into the flame war of you know all this, it's just not worth it.

Anyway, there you go. so there's all your details for your package. Once it in, there's your recommended Sa footprint. You know some people will not like it, others might, and your PCB package might actually have that particular thing up there.

for the small outline package. it may label it in that particular way. but yeah, important notice: Year: Don't probably don't use it in medical devices and stuff like that and they're very serious about that. By the way, you know if you're designing your chip into a medical device and it kills someone, they their army of lawyers will totally wash their hands of it.

Doesn't even mention medical in there I Don't know. Anyway, important notice, Whatever. So there you go: I Hope you enjoyed that I Know it's been a long video, but there's really no way to avoid that When you go through every single page of a datasheet in every single parameter and this is very simple: 7 4hc, Double O Quad NAND gate Imagine if we did it like a microcontroller data sheet or an FPGA datasheet or something like that I could do it like the video would literally be 24 hours long to do like an FPGA data with all its parameters and everything else. But anyway, if you found that useful, please give it a big thumbs up.

And as always, discuss down below: if you like this sort of vast screen captured datasheet type thing I can do more of them, please leave a comment down below if you wanted me to go through other types of data sheets, this one follows on nicely from the digital logic tutorials I've been doing recently, but if you've got suggestions for other data sheets you want to go through, then by all means we can do that. I Hope you enjoyed it. Catch you next time you.