Ultra small dual supply digital potentiometer

Hey,

I'm implementing a variable gain amplifier (+/-3V) and im currently using an Analog Devices AD5280 digital potentiometer. works quite well however it's size is unacceptable for our implant

There are some really tiny potentiometers out there (eg Maxim MAX5128, 2mm squared) but they are rated for 5.25 rail rail. Similiarly any other small one I have found is designed for max of +/- 2.5V, and rated at 5.25.

Im wondering if anyone might have an idea of some suitable device, small as possible preferable QFN package or similiar. Resistances of anywhere 10-100 k in a min of 128 steps is desirable

Thanks

col_implant said:

There are some really tiny potentiometers out there (eg Maxim MAX5128, 2mm squared) but they are rated for 5.25 rail rail. Similiarly any other small one I have found is designed for max of +/- 2.5V, and rated at 5.25.

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Read the datasheet...the MAX5128 can operate from 2.7V-5.5V

dknguyen said:

Read the datasheet...the MAX5128 can operate from 2.7V-5.5V

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Yes i does say that. However I have been in contact with Maxim apps engineers, the say dual supply operation has been verified for +/-2.5V

col_implant said:

Yes i does say that. However I have been in contact with Maxim apps engineers, the say dual supply operation has been verified for +/-2.5V

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Oh, I see. YOu need dual supply. I've can't remember ever hearing of anything that was of +/-3V personally. Maybe you have to find a +/-5V one and use it at 3V. I guess something like that might be labelled as 10V single supply.

would it be simpler to look for a ultra small amplifier instead, with variable gain built in? some fab plant marrying two or more ics at the silicon level will be far small than anything you'll come up with using discretes

Yea I have investigated variable gain amps, however they are quite large and high power (relative to my project)