What is the Difference between IIP3 and IPIP3?

Hi everybody. I would appreciate if anyone could help me with the differences between IPIP3 and IIP3. I think IIP3=IPIP3/Gain. Am I right? In AGCs usually IPIP3 is reported instead of IP3? why and what is it?

Thanks.

Hi,

IIP3 and OIP3 are different where the first one refers to the "input 3rd order intercept point" and the latter one refers to the "output 3rd order intercept point". Relationship between them is as you noted (OIP3 = IIP3 + Gain (in dB)), however I think IPIP3 is just another notation for IIP3. They should refer to the same phenomenon.

Hi I think the same, but I'm completing a systematic project and the IP3 specifications of AGCs in this system are introduced by IPIP3, while the other blocks use IIP3. Furthermore the IPIP3 of these AGCs are very low (-37 dBm) while the preceding block before AGC has a IIP3 of 7 dBm. I think its a bit abnormal! what do think?

Thanks.

It is interesting. Maybe that AGC is for very low power applications (e.g., some sensing circuits or circuits for satellite communication etc.). You can check out if there is any application note that includes that AGC part and then you may ensure if it matches your purposes or not.

Of course, still there may also be a notational issue about IPIP3 and IIP3.