#1109 Analog Switches 4066 DG201

[Music] all right one of the chips that was recommended i do a video on is a legendary 4066 uh back from the old motorola 4000 series days four four oh six six this one's a motorola part this is an mc1466 so sometimes they put it one in front of it but in the old days was just four four four oh six cd 4066 or uh other kinds of 406 sixes um there are there are more modern 406 sixes this is one this is in 74 hc 4066 so uh the hc series continued to con uh bank the um the 406 six so what is a 406 six okay let's look at the data sheet over here uh 406 is a analog switch so what is an analog switch well you can think of it as a solid state relay okay there are two contacts and then and then a switch and the switch is made out of fet transistors so it's electronic and there's a lot of switching you can do with digital electronics but they're always one direction right you can even just use like an and gate as a switch you know if the other side's a zero then the and function won't allow a signal capacitor but if one side it has a high then then it will pass it so you can just use regular logic as a switch but to have it bi-directional be able to send signal in or signal out is specific to a switch and also it's an analog switch which means it doesn't have to have a high state or a low state it can have any any voltage at all and it will go back and forth just like a relay would now uh unlike a relay these have a pretty bad on resistance okay these are going to have like a 50 ohm on resistance and so it's not a very good switch for low omega um it's like i said it's about 50 ohms so if that's okay then then these these types of switches are great um the old part here so here's like a a diagram of it not a great diagram of how uh how a switch works here this is a better demographic how a switch works um there's an input and an output that's and then there's these two fets that act as a switch there's an n-type and a p-type it allows you to have the the the voltage going this away or the voltage going this away it works it works in both polarities and then you'll have something like this and then you can turn this thing on and off it'd be an enable pin to turn this thing on or off and it's usually at regular digital logic levels over here either the cmos if it's a cmos part or ttl if it's a tdl part okay so this particular ship where the [Applause] the 4066 okay let's see what it says it can operate from two to six volts has a switch time of 18 nanoseconds that's pretty quick um and that's because it's the hc version okay the old versions the regular 4066 are going to be around 100 nanoseconds they're going to be quite slow but this one's pretty fast this one is uh this one's 18 nanoseconds switch time with the hc version um yeah on state resistance about 50 ohms um you can use this thing for analog multiplexing chopping uh okay motor speed control interesting dc dc converter all kinds of stuff but this one is a quad switch so this one has four four switches in in in one package okay so let's go ahead and turn one on just for fun all right so i have the switch hooked up here and it's normally on if i push the button it turns it off and i am connecting an ohm meter across the switch so we're getting about 34 ohms and if i push the off switch it goes to high state which is 171 k ohms something like that or maybe higher the leakage of these things are pretty good and the crosstalk is pretty good you can get all of the data off of the data sheet but um uh the isolation is great between these things it doesn't have a lot of uh capacitance and stuff there switches are pretty nice um anyway so that's that's the way it works it is a switch and it is bi-directional so we can measure measure the ohmage in both ways 33 ohms in that direction if i go in this direction it is 34 ohms same thing um so uh it works works in both there we go it's a yeah so it's just kind of leakage 15 mega ohms yeah it's it's very good in the offset it's very very good anyway so that is the uh 406 six and i would recommend if you want to use a 406 six to get the the hc part the 74 hc 406 six that's a much better parked in the old days um but even better okay the problem with these is going to be that the range of analog voltages you can send through this part are still going to be between 0 and vcc so if you have 5 volts hooked up to it really you can only switch voltages that are between zero and five volts it'd be nice to have an analog switch that actually worked with like op-amp circuits and stuff you know plus minus 12 volts things like that okay well fortunately there are such devices so um we'll take a look at one here this is a very old one this is a dg201 so let's look at a um a data sheet on that part all right so this is a industry standard um so yeah there's a lot of parts in the dg series dg201 301 401. there's a whole bunch of series of uh of analog devices that all kind of have similar pin outs and kind of have been standardized the dg2 one is quite old it says obsolete product please use the dg441 uh i actually have one of those yeah here's a here's a dg4401 um so it's a newer part um this one is uh switches 250 nanoseconds um now the cool thing about this is see you let's say you're using it with plus and minus 15 volts as the supply for this thing um you can you can switch signals that are 28 volts peak to peak right that's pretty cool um so you can put in a pretty big pretty big signals into this thing and here's the uh the quad nature of it it's four uh four four in a package here okay so let's let's hook this one up and uh see how he how he does all right so we have the dg201 in here we have plus or minus uh plus minus 12 volts on it and uh we'll measure the contact resistance of this switch and it's a little higher it's uh bouncing about bouncing around a bit here probably picking up some noise but yeah around around 100 ohms and that's what the data sheet says this one this one has a um on resistance of about about a hundred ohms okay but it has a much higher uh factor um for the amount of um a bigger a bigger voltage range right now this is supposed to be compatible with a uh four four one so let's let's let's see if that's true we'll pull out this part we'll live switch it here right on camera we'll take a 441 and uh pop him in and see how he does all right and uh better part okay it's it's upgraded right it's only it's only 40 ohms uh on resistance and uh yeah there you go and if i uh if i disable the uh disable the input here let me pull the uh whoops i'm running out of hands here let me pull the input high so it will turn off and yeah there we go i think you can see it's in the megome range every once in a while pops up to like you know 19 mega ohms anyway yeah it's definitely off um and then if we ground the input uh we turn it back on and it goes to 50 ohms so yeah there you go anyway so um if you are going to put these in analog circuits definitely go for the more modern parts the dg400 parts things like that so they'll do you they'll do you good okay so um how would you how would you really use these parts in a circuit okay let's take a look at that all right well there's a there's a there's a million and one ways to use a switch right you know we have we have a switch so let's say that we have uh an arduino okay arduino and we are going to measure uh we're usually going to use the a to d on the arduino okay and so we want to measure several things we only want to use one pin of the arduino so we want to measure several things so this is a quad a quad switch right so we get we get four of these things okay so we could wire them up like this and measure four different things depending on which one we close right if we want to measure this you know we want to measure a b c or d we'll just we'll just close one of these right um you also can say okay well i want to be i want to check my offsets and stuff too so one of these can be ground so you can you can like measure your ground um there are there are fancy chips that have a whole bunch of multiplexers uh i mean a whole bunch of switches built in them called multiplexers and so you don't have to build them out of discrete switches you can you can get one that's maybe a you know an eight-way multiplexer and measure a bunch of things i've used those before you can also use them in some kind of analog circuit let's say you have oh let's say you have some kind of circuit you've got a you've got an inverting amplifier okay and um let's say you've got a um let's see you want to all right so i'm going to i'm going to have a circuit like this i'm going to have either a gain of let's say a gain of 10. so this is a time so that's times 100 escape this is times 100 and this is times one okay and then that goes into the next stage okay so next stage is over here all right well we could put an analog switch here and we could put an analog switch here right and we can choose do we want to have a gain of 100 do we want to have a gain of one right and uh we can control that with an arduino we can say yeah you get to choose right or maybe you have a a inverting amplifier and a non-inverting amplifier do you want to have negative gain you want to have positive gain right um or i mean there's just a thousand reasons you can chop things you can switch things that maybe you don't want to uh have noise get through the system you want to kind of have isolate and stuff you can kind of use a poor man's isolation by using a fet switch between the two circuits but yeah fet switches yes think about them like i said they are bi-directional there are other ways to do things unidirectional but these things are bi-directional allow the allow the electrons to go forwards and backwards now here's a circuit you could do you could have it uh you could have this circuit ramp up right it's ramping up and then you could say whoop you know discharge a womb then it's going to ramp up again and uh you know you might want to have this as a sample and hold and you need to reset your sample and hold sometimes use use a fence switch all right so that was a quick introduction uh to the 4066 and in general fat switches they come in all sorts of different voltages and configurations you know here's one that has uh normally open and normally closed in the same package so that might be that might be handy in some cases so yeah um take a look at these uh most of them that are interesting that i find are in the in the gg series gg 300 400 500 type of things so yeah take a look at the take a look at the data sheets you

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Keywords: s100, s-100, cpm, cp/m, cpm80, intel 8080, 8080, 8085, zilog z80, vintage computer, vintage computing, IMSAI, IMSAI 8080, ALTAIRTTL CPU, cpu design, eagle cad, eagle pcb, 8-bit CPU, 8bit CPU, diy cpu, 74181, 74381, 74382, ALUZeta, Zeta2, ROMWBW, Zeta SBCelectronic test equipment, vintage electronics, DIY electronics, electrical engineering, electronic engineering, electronics, PCB design, Circuit design

Id: y9jRu-2knSM

Length: 13min 52sec (832 seconds)

Published: Thu Apr 21 2022