CD 4067 & 74154 pattern

[rajaram04]

Hello sir

what is the diffrence between a CD 4067 & 74154 ?
Which one has an extra feature ?

 

[barry]

The difference is that these are two completely different devices. One is an analog multiplexer/demultiplexer, the other is a digital 4 line-16 line decoder. And one is TTL and the other is CMOS. Of course, if you had bothered to read the data sheets, you would know this already.

 

[rajaram04]

The difference is that these are two completely different devices. One is an analog multiplexer/demultiplexer, the other is a digital 4 line-16 line decoder. And one is TTL and the other is CMOS. Of course, if you had bothered to read the data sheets, you would know this already.

hmm exactly
so is it possbile to make controls over sound signal by using cd 4067 ?
it has a common out

 

[barry]

You want to switch audio? This is not the best device for the purpose (linearity, cross-talk, etc.) Yes, you can switch audio signals with it.

 

[rajaram04]

okk sir so how to switch audio in such an electronic way ?

 

[barry]

Do you have any specifications?

 

[rajaram04]

Do you have any specifications?

hmm ya i have sir .

i have musical instruments for which i am making a digital volume control of my own

This volume control ll be present in between my instruments & any P.A system (mixer ampli etc)

& No i don't want to use available i.c. chips as they are not available easily here so please help me in above cases

 

[barry]

Not sure how an analog mux has anything to do with a digital volume control, but you need to look at the data sheet and verify that your voltage levels are compatible with the device. For instance, your input voltage can't go any lower than about 0.5V below ground.

 

[rajaram04]

Not sure how an analog mux has anything to do with a digital volume control, but you need to look at the data sheet and verify that your voltage levels are compatible with the device. For instance, your input voltage can't go any lower than about 0.5V below ground.

hmm i found something here please refer

 

[barry]

Wowee! Talk about overkill!! You could do that all with a single chip. See link (there are lots and lots and lots of companies that make digital pots.)


**broken link removed**

 

[betwixt]

This is a duplicate of https://www.edaboard.com/threads/288204/.

I don't think Rajaram understands the concept of multiplexers or analog switches.

Brian.

 

[rajaram04]

Re: CD 4067 & 74154 pattern

no the whole story ends here coz again its a circle of eight but what i am discussing here is only cd 4067 comparing with 74 154 & so i started a new thread in another way see above discussion & you can see things diffrent from, that thread

- - - Updated - - -

no the whole story ends here coz again its a circle of eight but what i am discussing here is only cd 4067 comparing with 74 154 & so i started a new thread in another way see above discussion & you can see things diffrent from, that thread

 

[barry]

Re: CD 4067 & 74154 pattern

no the whole story ends here coz again its a circle of eight but what i am discussing here is only cd 4067 comparing with 74 154 & so i started a new thread in another way see above discussion & you can see things diffrent from, that thread

- - - Updated - - -

no the whole story ends here coz again its a circle of eight but what i am discussing here is only cd 4067 comparing with 74 154 & so i started a new thread in another way see above discussion & you can see things diffrent from, that thread

I have no idea what you are talking about. You started off asking how two totally different chips were different, and then you post a schematic of a digital resistor.

 

[rajaram04]

Re: CD 4067 & 74154 pattern

I have no idea what you are talking about. You started off asking how two totally different chips were different, and then you post a schematic of a digital resistor.

ya that i did so . . its just an example i wanted to show you as i asked about the audio line property related to cd 4067

just its an example to know about how it plays role in other than digital outs as you told both chips are diffrent

thats why i asked about its property if it is true or not

 

[betwixt]

Ok, back to basics:

The 75154 is a DIGITAL 4 to 16 decoder/multiplexer. You put a four bit (0000 to 1111) binary number into the ABCD inputs and ONE of the 16 outputs is selected. Whether that output is high or low depends on what you put into the G1 and G2 inputs. The pins accept and produce ONLY TTL level signals, the device will not carry analog signals at all.

The CD4067 (which I believe is obsolete anyway) is an ANALOG CMOS switch. You put a four bit (0000 to 1111) binary number into the ABCD inputs and ONE of the 16 switched outputs is connected internally to the common pin. Think of it as being like a mechanical 16 way single pole switch with the position decided by the ABCD inputs. It CAN carry low-level audio although it's internal resistance is quite high and it's linearity isn't very good.

So apart from both having four selection inputs, their function is quite different. You cannot use either type as a volume control although you can use the CD4067 to select different volume levels IF you produce those levels with other components and use it to select ONE of them.

Brian.