Title :
A Highly Linear Direct-Conversion Transmit Mixer Transconductance Stage with Local Oscillation Feedthrough and I/Q Imbalance Cancellation Scheme
Author :
Lee, Charlotte P. ; Behzad, A. ; Ojo, D. ; Kappes, Manfred ; Au, S. ; Meng-An Pan ; Carter, Kevin ; Tian, Shiwei
Author_Institution :
Broadcom, San Diego, CA
Abstract :
A linear transconductance stage with process insensitive gain control and gain insensitive output offset current is proposed. A calibration scheme to remove the LO feedthrough (LOFT) and I/Q imbalance is also introduced. The prototype achieves 3rd-order IMD suppression better than 52dBc, LOF suppression better than 32dBc, and image rejection better than 46dBc for all gain settings. The transmit chain achieves an 802.11a EVM of < -40dB
Keywords :
CMOS integrated circuits; gain control; mixers (circuits); radio transmitters; wireless LAN; 802.11a EVM; I/Q imbalance cancellation scheme; IMD suppression; LO feedthrough elmination; LOF suppression; LOFT; gain insensitive output offset current; linear direct-conversion transmit mixer stage; linear transconductance stage; local oscillation feedthrough; process insensitive gain control; Baseband; Change detection algorithms; Circuits; Envelope detectors; Gain control; Gold; Local oscillators; Radio transmitters; Transconductance; Wireless LAN;
Conference_Titel :
Solid-State Circuits Conference, 2006. ISSCC 2006. Digest of Technical Papers. IEEE International
Conference_Location :
San Francisco, CA
Print_ISBN :
1-4244-0079-1
DOI :
10.1109/ISSCC.2006.1696195
