Cadance-IIP3 problem...

[visionbjp]

It is easy when I used ports
but what I need is to use i_source in the input
and port at the output

in this case input is in current (Ampere / not in dB)
How can I check IIP3

I am working on current amp

 

[pavel_adameyko]

Hi, visionbjp.
As I understand, current amplifier is the device which amplify current so why you can't define IIp3 in terms of current - for example in dBA.
Regards.

 

[visionbjp]

Hi, visionbjp.
As I understand, current amplifier is the device which amplify current so why you can't define IIp3 in terms of current - for example in dBA.
Regards.

So I have ploted with current on the x-axis
and took 20log (i_in)

but the problem is I can't know whether it is good or not~
because I can't compair it with usual IIP3 that where on dBm

 

[pavel_adameyko]

but the problem is I can't know whether it is good or not~
because I can't compair it with usual IIP3 that where on dBm

Usually iip3 specified in dBm for voltage-mode devices, but in your case is different, i think. By the way, you can convert iip3 from dBA to dBm using, for example, 50 Ohm reference impedance.

 

[visionbjp]

but the problem is I can't know whether it is good or not~
because I can't compair it with usual IIP3 that where on dBm

Usually iip3 specified in dBm for voltage-mode devices, but in your case is different, i think. By the way, you can convert iip3 from dBA to dBm using, for example, 50 Ohm reference impedance.

well you can't say dBm is used in voltage-mode, usual circuits that we use are matched-mode(50ohm)
in voltage mode input impediance is very large, on the other hand current mode has very small input impediance
So I am gussing dBV for voltage-mode and dBA for current-mode

but still cant know how much dBA is enought for linear amp
eg) IIP3 over 20dBm at 10dB gain is thought to be good ( there are lots of references...)

 

[pavel_adameyko]

but still cant know how much dBA is enought for linear amp
eg) IIP3 over 20dBm at 10dB gain is thought to be good ( there are lots of references...)

Can you give me one for such amplifier?