DIYbanter - Analog Switch

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On Sat, 23 Aug 2014 14:53:56 -0700, Jim Thompson
wrote:

Anyone know of an analog switch that can handle -6V to +11V inputs
(low current, high Ron OK), +/-12V supplies?

...Jim Thompson

DG408 family.

On 8/23/2014 5:53 PM, Jim Thompson wrote:
Anyone know of an analog switch that can handle -6V to +11V inputs
(low current, high Ron OK), +/-12V supplies?

I've been using the ADG1411YRUZ which is pin compatible with a Maxim
part but in a slightly different package. They have the same pitch but
different body widths so a footprint can be used which will work with
both. I'd have to dig up a Maxim PN since we have never used them in
production. It might be MAX4662. The Maxim part has a logic supply pin
and the ADI part does not. The Maxim part also goes high impedance when
not powered which the ADI part does not, if I remember.

--

Rick

On Sun, 24 Aug 2014 03:46:10 -0400, rickman wrote:

On 8/23/2014 5:53 PM, Jim Thompson wrote:
Anyone know of an analog switch that can handle -6V to +11V inputs
(low current, high Ron OK), +/-12V supplies?

I've been using the ADG1411YRUZ which is pin compatible with a Maxim
part but in a slightly different package. They have the same pitch but
different body widths so a footprint can be used which will work with
both. I'd have to dig up a Maxim PN since we have never used them in
production. It might be MAX4662. The Maxim part has a logic supply pin
and the ADI part does not. The Maxim part also goes high impedance when
not powered which the ADI part does not, if I remember.

Thanks to all!

Anyone know of a Spice model? I can wing it behaviorally (it's an
audio application), but the customer would be more impressed if I had
an ADI model ;-)

...Jim Thompson
--
| James E.Thompson | mens |
| Analog Innovations | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| San Tan Valley, AZ 85142 Skype: skypeanalog | |
| Voice:(480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |

I love to cook with wine. Sometimes I even put it in the food.

On Sun, 24 Aug 2014 11:17:58 -0700, Jim Thompson
wrote:

On Sun, 24 Aug 2014 03:46:10 -0400, rickman wrote:

On 8/23/2014 5:53 PM, Jim Thompson wrote:
Anyone know of an analog switch that can handle -6V to +11V inputs
(low current, high Ron OK), +/-12V supplies?

I've been using the ADG1411YRUZ which is pin compatible with a Maxim
part but in a slightly different package. They have the same pitch but
different body widths so a footprint can be used which will work with
both. I'd have to dig up a Maxim PN since we have never used them in
production. It might be MAX4662. The Maxim part has a logic supply pin
and the ADI part does not. The Maxim part also goes high impedance when
not powered which the ADI part does not, if I remember.

Thanks to all!

Anyone know of a Spice model? I can wing it behaviorally (it's an
audio application), but the customer would be more impressed if I had
an ADI model ;-)

...Jim Thompson

It's just a switch, pretty simple, not the sort of things that people
furnish models for. The only tricky parts are charge injection and
what happens if the analog inputs try to go past the supply rails.

On 25/08/2014 04:32, John Larkin wrote:
On Sun, 24 Aug 2014 11:17:58 -0700, Jim Thompson
wrote:

On Sun, 24 Aug 2014 03:46:10 -0400, rickman wrote:

On 8/23/2014 5:53 PM, Jim Thompson wrote:
Anyone know of an analog switch that can handle -6V to +11V inputs
(low current, high Ron OK), +/-12V supplies?

I've been using the ADG1411YRUZ which is pin compatible with a Maxim
part but in a slightly different package. They have the same pitch but
different body widths so a footprint can be used which will work with
both. I'd have to dig up a Maxim PN since we have never used them in
production. It might be MAX4662. The Maxim part has a logic supply pin
and the ADI part does not. The Maxim part also goes high impedance when
not powered which the ADI part does not, if I remember.

Thanks to all!

Anyone know of a Spice model? I can wing it behaviorally (it's an
audio application), but the customer would be more impressed if I had
an ADI model ;-)

...Jim Thompson

It's just a switch, pretty simple, not the sort of things that people
furnish models for. The only tricky parts are charge injection and
what happens if the analog inputs try to go past the supply rails.

Some analog switches do some fairly odd things to get lower
on-resistance, like driving the back-gate (well) that one of the pass
transistors sits in. They switch the back-gate either to one of the
supply rails (to prevent diodes conducting when it is off) or to the
signal path (to reduce on-resistance when it is on). If they don't get
the non-overlapping gate drive right for the switches that drive the
backgate, then the signal path gets momentarily shorted to one of the
supply rails, which is not great in switched capacitor circuits, where
you probably want charge to be conserved, and could give an unwanted
kick to other circuits too. Even if they get the non-overlapping gate
drive just right, some chunk of charge mysteriously disappears from the
signal path into the well, to charge up the well when the switch
operates. For some things the 4016 is better than the 4066, even if the
on-resistance might be worse.

If you were designing a circuit where you care about charge going
missing, or distortion due to variation of on-resistance with signal
voltage, or distortion due to junction capacitance varying with signal
voltage, then you might want a transistor level model.

Chris

On 8/23/2014 4:53 PM, Jim Thompson wrote:
Anyone know of an analog switch that can handle -6V to +11V inputs
(low current, high Ron OK), +/-12V supplies?

...Jim Thompson

LTSpice has one (or more).