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Abstract: This paper presents an approach for analyzing the key parts of a general digital radio frequency (RF) charge sampling mixer based on discrete-time charge values. The cascade sampling and filtering stages are analyzed and expressed in theoretical formulae. The effects of a pseudo-differential structure and CMOS switch-on resistances on the transfer function are addressed in detail. The DC-gain is restrained by using the pseudo-differential structure. The transfer gain is reduced because of the charge-sharing time constant when taking CMOS switch-on resistances into account. The unfolded transfer gains of a typical digital RF charge sampling mixer are analyzed in different cases using this approach. A circuit-level model of the typical mixer is then constructed and simulated in Cadence SpectreRF to verify the results. This work informs the design of charge-sampling, infinite impulse response (IIR) filtering, and finite impulse response (FIR) filtering circuits. The discrete-time approach can also be applied to other multi-rate receiver systems based on charge sampling techniques.

[1]Abidi, A.A., 2004. RF CMOS comes of age. IEEE J. Sol.-State Circ., 39(4):549-561.

[2]Bagheri, R., Mirzaei, A., Chehrazi, S., Heidari, M., Lee, M., Mikhemar, M., Tang, W., Abidi, A.A., 2006. An 800MHz to 5GHz Software-Defined Radio Receiver in 90 nm CMOS. IEEE Int. Conf. on Solid-State Circuits, p.1932-1941.

[3]Chen, D.Y., Wang, W., Kwasniewski, T., 2007. Design considerations for a direct rf sampling mixer. IEEE Trans. Circ. Syst. II: Expr. Briefs, 54(11):934-938.

[4]Ho, Y.C., Staszewski, R.B., Muhammad, K., Hung, C.M., Leipold, D., Maggio, K., 2006. Charge-domain signal processing of direct RF sampling mixer with discrete-time filter in Bluetooth and GSM receiver. EURASIP J. Wirel. Commun. Netw., 2006:1-14.

[5]Karvonen, S., Riley, T.A.D., Kurtti, S., Kostamovaara, J., 2006. A quadrature charge-domain sampler with embedded FIR and IIR filtering functions. IEEE J. Sol.-State Circ., 41(2):507-515.

[6]Kundert, K., 2003. Hidden State in SpectreRF. Available from http://www.designers-guide.org [Accessed on Dec. 8, 2006].

[7]Kundert, K., Zinke, O., 2004. The Designer’s Guide to Verilog-AMS. Kluwer Academic Publishers, Boston.

[8]Muhammad, K., Staszewski, R.B., 2004. Direct RF Sampling Mixer with Recursive Filtering in Charge Domain. Proc. Int. Symp. on Circuits and Systems, p.577-580.

[9]Muhammad, K., Staszewski, R.B., Leipold, D., 2005. Digital RF processing: toward low-cost reconfigurable radios. IEEE Commun. Mag., 43(8):105-113.

[10]Staszewski, R.B., Muhammad, K., Leipold, D., Hung, C.M., Ho, Y.C., Wallberg, J.L., Fernando, C., Maggio, K., Staszewski, R., Jung, T., et al., 2004. All-digital TX frequency synthesizer and discrete-time receiver for Bluetooth radio in 130-nm CMOS. IEEE J. Sol.-State Circ., 39(12):2278-2291.

[11]Staszewski, R.B., Muhammad, K., Leipold, D., 2005. Digital RF Processor (DRP) for Cellular phones. IEEE/ACM Int. Conf. on Computer-Aided Design, p.122-129.

[12]Xu, G., Yuan, J.R., 2000. Comparison of Charge Sampling and Voltage Sampling. Proc. 43rd IEEE Midwest Symp. on Circuits and Systems, p.440-443.

[13]Xu, G., Yuan, J.R., 2005. Performance analysis of general charge sampling. IEEE Trans. Circ. Syst. II: Expr. Briefs, 52(2):107-111.