Calibration techniques of active BiCMOS mixers

This paper describes calibration techniques for downconversion mixers used in integrated direct-conversion receivers. A method of achieving a high even-order intermodulation rejection is presented. Using the method presented, the receiver second-order input intercept point (IIP2) can always be improved by more than 20 dB. The minimum achieved receiver IIP2 after calibration is +38 dBm. A technique to enhance the I/Q-amplitude balance between the quadrature channels is also introduced. A single-balanced adjustable mixer is implemented as a part of a prototype direct-conversion receiver. The receiver chip consists of a low-noise amplifier, mixers and calibration circuitry, a divide-by-two circuit, local oscillator (LO) buffers for LO generation, and active baseband filters. The chip is fabricated using a 0.35-/spl mu/m SiGe BiCMOS process and is characterized at 900 MHz.

[1]  K. Halonen,et al.  A dual-band RF front-end for WCDMA and GSM applications , 2001 .

[2]  Behzad Razavi,et al.  Design considerations for direct-conversion receivers , 1997 .

[3]  B. Bastani,et al.  A high IIP2 downconversion mixer using dynamic matching , 2000, IEEE Journal of Solid-State Circuits.

[4]  J.P.F. Glas,et al.  Digital I/Q imbalance compensation in a low-IF receiver , 1998, IEEE GLOBECOM 1998 (Cat. NO. 98CH36250).

[5]  L. Larson,et al.  A wide-bandwidth Si/SiGe HBT direct conversion sub-harmonic mixer/downconverter , 2000, IEEE Journal of Solid-State Circuits.

[6]  J. Ryynanen,et al.  A 22 mA 3.7 dB NF direct conversion receiver for 3G WCDMA , 2001, 2001 IEEE International Solid-State Circuits Conference. Digest of Technical Papers. ISSCC (Cat. No.01CH37177).

[7]  Kari Halonen,et al.  Characterization of IIP2 and DC-offsets in transconductance mixers , 2001 .

[8]  Willy Sansen,et al.  An integrated wide-band variable-gain amplifier with maximum dynamic range , 1974 .

[9]  H. Kokatsu,et al.  An I/Q active balanced harmonic mixer with IM2 cancelers and a 45/spl deg/ phase shifter , 1998, 1998 IEEE International Solid-State Circuits Conference. Digest of Technical Papers, ISSCC. First Edition (Cat. No.98CH36156).

[10]  C.D. Hull,et al.  A direct-conversion receiver for 900 MHz (ISM band) spread-spectrum digital cordless telephone , 1996, 1996 IEEE International Solid-State Circuits Conference. Digest of TEchnical Papers, ISSCC.

[11]  E. Main,et al.  Effects of offsets on bipolar integrated circuit mixer even order distortion terms , 2000, IMS 2000.

[12]  A. Abidi.  Direct-conversion radio transceivers for digital communications , 1995, Proceedings ISSCC '95 - International Solid-State Circuits Conference.