double 1:2 switch/multiplexer

[SneaKSz]

Hello guys,

is there someone out there that know a common double 1:2 switch.

for example : A1= 0V and A2=2.5V, then I select A2 and the ouput Z = 2.5V .

Kind regards!

 

[Reloadron]

I have no idea what you mean? Do you mean a DPDT (Double Pole Double Throw) switch where you can select between 1 of 2 inputs? The same could be done with a SPST (Single Pole Single Throw) switch if both signals shared the same common. If that is what you are getting at switches like that are very, very common globally. Additionally you don't mention it but I assume low current?

Ron

 

[SneaKSz]

Hi,

I want something like this : https://www.electro-tech-online.com/custompdfs/2012/03/74HC_HCT4053.pdf .

Uhm the current can go up to 5mA, is that a problem?

I'll take a look at those DPDT's and SPST's.

Thanks!

 

[Ian Rogers]

There are analogue switches https://www.electro-tech-online.com/custompdfs/2012/03/82545.pdf that will do what you want.

 

[Reloadron]

OK, you want a analog multiplexer/demultiplexer chip. I was thinking something like a physical manually operated switch. What you need to do is look at the On Resistances shown in the data sheet placing thought on your load(s).

<EDIT> Ian is pointing to a very good solution. That will give you what you want and again, note the nice low Ron (On Resistance). </EDIT>

Ron

 

[kubeek]

If you need lower on-resistance with max. 5V swing, the sn74cb3q3125 from TI worked very well for me.

 

[SneaKSz]

Hi Guys , thanks for al the reactions.

I think I found a suitable one : https://www.electro-tech-online.com/custompdfs/2012/03/CBT3126.pdf.

So if I apply a 2V input voltage and enable the OE, then the ouput would be 2V?

I think it will because it's just driving a FET.

The thing that got me confused was "11. AC waveform" fig 6, they apply a Vi and Vo go's to Voh..

Kind regards !

 

[Reloadron]

Figure 6 is only showing the propagation delay, and they label the points the delay is measured at. What part is confusing for you?

Ron

 

[SneaKSz]

I thought that, if they apply an input voltage of a certain amplitude the output would go to V output High.

Buf I can see it just like activating the gate of the FET and the channel will to open?

EDIT : Thanks IAN for the IC,

Kind regards

 

[kubeek]

They show Voh because they assume the output is loaded, so the output voltage isn´t exactly the same as input due to the On resistance.

 

[SneaKSz]

Ok and due to the current, but I can assume that It'll work when I apply a 2V input voltage and enable the OE, then the ouput would be 2V?

 

[kubeek]

Yes. Right now I am using the TI ones to switch between many simcards and it works fine. You can look at it as a relay with 5ohm contact resistance, but never forget that if you get above the supply rail the ESD protection diodes will start to conduct and will clamp your signal to Vcc+0.3.
Also another funny thing I measured is that if you leave the data pins floating and try to measure the on resistance you will get nonsense results, because the pins are very high impedance so they usually stay outside the supply voltage range, so the switch fets cannot open.

 

[SneaKSz]

Aha ok, I'll keep that in mind!

Is there also a version but 2:1?

EDIT : Somethings like this( dual) : https://www.electro-tech-online.com/custompdfs/2012/03/ADG5436.pdf

 

[kubeek]

There should be, but i never looked for one. You can allways use a pair of SPST and some logic to make a SPDT.