I'm looking into applications where I need to control the resistance of an element based on an input voltage... I started by looking at some FET characteristics... and they're not really linear, at all. Once you get into the saturation region, Vgs doesn't even matter and it's just messy.
I hunted around for a while, I found the VCR2N
http://pdf.datasheetcatalog.com/datasheet/vishay/70293.pdf
... and it's not exactly cheap... they can run you up to $10/unit in small volume. But I'm thinking it might fit my application... maybe
I have a few questions, maybe someone may have some experience.
First line - "ac drain-source resistance" so it's not bi-directional? One way resistor?
Later on - "This series of JFET is intended applications where the drain-source voltage is a low level ac signal with no dc comp." now we're getting into impedance, it's actually complex? also this contradicts my first question
Then this:
rDSbias - What's this? The resistance shifts as a function of Vgs, Vgsoff (Given a range from -3.5 to -7v), and rds
...So this is trying to tell me that the device is completely non-linear?
Later on i'm given some graphs and some other nice things with an app note explaining voltage divider...
Does anyone either have:
1. More info, or a link to more info, on this part?
2. A better/cheaper solution for a VCR?
I hunted around for a while, I found the VCR2N
http://pdf.datasheetcatalog.com/datasheet/vishay/70293.pdf
... and it's not exactly cheap... they can run you up to $10/unit in small volume. But I'm thinking it might fit my application... maybe
I have a few questions, maybe someone may have some experience.
First line - "ac drain-source resistance" so it's not bi-directional? One way resistor?
Later on - "This series of JFET is intended applications where the drain-source voltage is a low level ac signal with no dc comp." now we're getting into impedance, it's actually complex? also this contradicts my first question
Then this:
rDSbias - What's this? The resistance shifts as a function of Vgs, Vgsoff (Given a range from -3.5 to -7v), and rds
...So this is trying to tell me that the device is completely non-linear?
Later on i'm given some graphs and some other nice things with an app note explaining voltage divider...
Does anyone either have:
1. More info, or a link to more info, on this part?
2. A better/cheaper solution for a VCR?