Looking for Analog Switch with single supply

Best way is probably to create a -5V or whatever supply from your 5V, then use a switch that meets your other requirements.

Thanks.

I done a little research and I can't see any wide Vin switches that have a single supply rail.

We have limited the requirement to 2Vpeak and I can now add a Dc bias to use a single supply analog switch

Joe

Tbe way ICs work they generally need their substrate connected to a voltage about as negative as any input voltage. There are a very few ICs with an on-chip charge pump that actually creates a negative voltage, but probably you're better off separating the functions if you need a negative supply.

That could work too. If you exceed the supply rails by more than a few hundred mV you can destroy the chip unless the current is limited.

CD4066?

I've seen a few maxim audio switches that had built in inverters to generate the negative rail.

I'm planning to use the analog devices ADG714/715 for a new project. 8 spst switches, 2.5ohms on resistance, 2.7 to 5.5 volts songle rail and spi compatable serial control in a 24 lead tssop package. All inputs will have an offset bias at 2.5 volts to get bipolar capability.

AD have other similar devices as well...

Regards,

Chris

Relay.

John

Did you check the 4316 CMOS switch (4000 cmos family)?

The optoisolators that use a LED input and photoresistor output (Clairex used to make 'em) would do this. Catalog descriptions won't call them 'analog switch', though, so it's easy to overlook.

Actually, with UV and blue LEDs, it should be possible to make some very good ones; are there any out there in the market, or does one have to build 'em from scratch?

Along the vein that whit3rd suggests, something like a AQV210 (or in that general family) might work.

My ON-Semi LVX405x parts can run single supply or split... logic is always relative to GND. ...Jim Thompson

Yeah.... might be the simplest option depending on MTBF relay switchinig requirements.

Joe

Some of the opto-fet solid-state relays make excellent analog switches, especially if you only need an spst switch.

John

That's a neat part. I'd use it but I really need about double the swing. I'm using ADG442s and 452s now, with a MicroChip SPI I/O expander. The combination is a lot more than $4.

Double the swing ?. They are rail to rail at any vcc in the range.

Cost isn't an issue here at this stage, as it's more of a 'what if' project. Trying to evaluate some ideas about continuous rate integration with a cheap si labs micro dev kit and it's a-d and mux to sequence all the states and switch closures.

More convenient to have min chip count for layout reasons now and worry about the costs later if it all works...

Regards,

Chris

Where "any VCC" is 5V. I need at *least* 8V and 10V would be nice. I use them in a matching network and the voltage is defined by external specifications.

Cost wasn't an issue until we started shipping. Then management changed the definition of "important". The good news is that now it's not hard to look good. ;-)

Low chip count is good. Board real estate, pick-n-place, and inventory aren't free.

Sorry, missed that. Can you scale the voltage to suit the devices, then rescale in the software, or following op amp ?, You would obviously need >8v Vcc to handle that at some stage though...

Regards,

Chris

No, as I mentioned, it's a balancing network (hybrid circuit) for a line that sees 8Vish. While it doesn't hook the line it's on a mirror of the line. The next iteration I'll likely do a "fake resistor" and "fake capacitor" so won't need the switches at all. I would have before but I couldn't get the simulator to converge before I ran out of time.

Did some pots work some years ago where we used to92 type power mosfets as the switching element, the logic compatable gate drive types. You can also run two of them back to back to get bipolar capability.

Have also seen mosfets used at a higher voltage and power level in the dc arm of a bridge circuit to control induction motors, but this is probably irrelevant for your application...

Regards,

Chris