Seven GHz high gain 0.18 mu m CMOS gilbert downconverter with wide-swing cascode current mirrors

Abstract

A downconversion micromixer with low-voltage cascode current mirrors at both transconductor and load stages has been implemented using the 0.18-mu m CMOS technology in this article. This micromixer has a single-to-differential RF input transconductor formed by the NMOS wide-swing cascade current mirror, while the PMOS wide-swing cascode current mirror is also employed to improve conversion gain. A super source follower is used at the output to reduce the output impedance and to transfer more power to the load. This fully integrated downconverter has the high conversion gain of 16 dB and high LO-to-IF isolation of 50 dB at 7 GHz. The current consumption of the mixer core is 1 mA at 1.8 V supply voltage. Thanks to the low-voltage operation property of the wide-swing cascode current mirror, six transistors can be stacked within 1.8 V supply voltage. (c) 2007 Wiley Periodicals, Inc.