Author Topic: analogue switches  (Read 3112 times)

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Offline akis

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analogue switches
« on: April 11, 2014, 05:33:43 pm »
Hello, I am looking for an analogue switch in an IC so that I avoid having to run signal on long wires to a panel mounted mechanical switch. The signal will be analogue at about 200KHz and the amplitude will be about 10-12V peak. I have already used a Solid State Relay LH1510AT quite successfully except it is SPST and pricey. I was looking for more options like 2 pole 4 position as an example, all packed in a small IC. Many thanks
 

Offline PedroDaGr8

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Re: analogue switches
« Reply #1 on: April 11, 2014, 06:14:04 pm »
Hello, I am looking for an analogue switch in an IC so that I avoid having to run signal on long wires to a panel mounted mechanical switch. The signal will be analogue at about 200KHz and the amplitude will be about 10-12V peak. I have already used a Solid State Relay LH1510AT quite successfully except it is SPST and pricey. I was looking for more options like 2 pole 4 position as an example, all packed in a small IC. Many thanks

Maxim and others make a wide range of analog switch ICs. In the <80V range they have a range of configurations that at most you can get is dual pole (1, 2, 3 or 4 switches in one IC).
« Last Edit: April 11, 2014, 06:16:02 pm by PedroDaGr8 »
The very existence of flamethrowers proves that some time, somewhere, someone said to themselves, "You know, I want to set those people over there on fire, but I'm just not close enough to get the job done." -George Carlin
 

Offline akis

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Re: analogue switches
« Reply #2 on: April 13, 2014, 08:42:11 am »
I have looked and discovered a range of switches which seem to be an industry standard, eg DG201, DG451 and so on, they are still quite expensive and they are single pole single throw mostly, whereas I was looking for one pole four position or six position type of thing. The lower the Ron the more expensive they are in general, although it appears Vishay is much cheaper than AD.

So I designed a silly diagram of a mosfet switch using N-channels. It has great drawbacks, it needs a Vdd much higher than the highest peak of the analogue signal expected. And if I use P-channels, again, I would need a Vee much lower than the lowest peak of the analogue signal.
 

Offline Skimask

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Re: analogue switches
« Reply #3 on: April 13, 2014, 09:36:21 pm »
ADG1406/1407/1408/etc.  Beware they only come in SMD packages, and a handful of other gotcha's...
I didn't take it apart.
I turned it on.

The only stupid question is, well, most of them...

Save a fuse...Blow an electrician.
 

Offline akis

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Re: analogue switches
« Reply #4 on: April 17, 2014, 08:55:15 am »
Thanks. I went and ordered the DG412. It has a pin labelled VL. I have no idea what it is. Could someone please tell me?
 

Offline miguelvp

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Re: analogue switches
« Reply #5 on: April 17, 2014, 09:09:43 am »
Thanks. I went and ordered the DG412. It has a pin labelled VL. I have no idea what it is. Could someone please tell me?

From http://datasheets.maximintegrated.com/en/ds/DG411-DG413.pdf
Page 6
Quote
VL must be connected to +5V to be TTL compatible, or to V+ for CMOS-logic level inputs
 

Offline akis

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Re: analogue switches
« Reply #6 on: April 17, 2014, 10:19:32 pm »
Ahh so much better a datasheet than Vishay's. It also talks about correct sequencing of the power supplies, another factor I had not considered.
 


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