An IIP2 calibration technique for direct conversion receivers

An improvement for a previously published IIP2 calibration method for a Gilbert cell type mixer is introduced. In the previous solution the IIP2 was degraded as a function of the baseband frequency when a mixer with RC load was used. This solution maintains a high IIP2 over the entire baseband channel in wideband systems. In order to implement an on-chip tuning engine the correct trimming code has to be detected. Two different solutions for the detection of the correct trimming code are discussed in this paper.