Improving Receiver Close-In Blocker Tolerance by Baseband $G_m-C$ Notch Filtering

This paper presents a receiver front end with improved blocker handling implemented in a 65-nm CMOS technology. Since close-in blockers are challenging to reject at RF, the receiver features a baseband (BB) notch filter, which effectively sinks close-in blocker current directly from the output of an LNTA and passive mixer structure. The notch-filter frequency can be tuned to match the blocker offset frequency, and the measurements indicate a significant improvement in the overall front-end interference robustness, while sensitivity remains unaffected. To optimize notch performance, the BB impedance is analyzed in detail. The front-end RF range is 750 MHz–3 GHz with an RF channel bandwidth of 20 MHz corresponding to 10-MHz BB bandwidth. The notch frequency is programmable from 16, which is less than one octave from the channel edge, up to 160 MHz. The gain-compression improvement is upto 9 dB, while IIP2 can be increased by more than 26 dB without calibration and IIP3 is 1 dBm. The current overhead for the notch function is between 7.5 and 30 mA, but it only exists under strong blocker conditions as the notch filter can be switched OFF if strong blockers are absent. The total front-end current consumption excluding the notch filter varies with LO frequency from 31 to 44 mA from a 1.2-V supply.

[1]  Eric A. M. Klumperink,et al.  24.3 A high-linearity CMOS receiver achieving +44dBm IIP3 and +13dBm B1dB for SAW-less LTE radio , 2017, 2017 IEEE International Solid-State Circuits Conference (ISSCC).

[2]  Antje Sommer.  Design Of Analog Filters 2nd Edition , 2016 .

[3]  Bram Nauta,et al.  A CMOS transconductance-C filter technique for very high frequencies , 1992 .

[4]  B. Nauta,et al.  The Blixer, a Wideband Balun-LNA-I/Q-Mixer Topology , 2008, IEEE Journal of Solid-State Circuits.

[5]  J.C. Leete,et al.  Analysis and Optimization of Current-Driven Passive Mixers in Narrowband Direct-Conversion Receivers , 2009, IEEE Journal of Solid-State Circuits.

[6]  Rinaldo Castello,et al.  SAW-less analog front-end receivers for TDD and FDD , 2013, 2013 IEEE International Solid-State Circuits Conference Digest of Technical Papers.

[7]  B. Nauta,et al.  Wideband Balun-LNA With Simultaneous Output Balancing, Noise-Canceling and Distortion-Canceling , 2008, IEEE Journal of Solid-State Circuits.

[8]  Imad ud Din,et al.  A receiver for LTE Rel-11 and beyond supporting non-contiguous carrier aggregation , 2013, 2013 IEEE International Solid-State Circuits Conference Digest of Technical Papers.

[9]  Eric A. M. Klumperink,et al.  Systematic comparison of HF CMOS transconductors , 2003, IEEE Trans. Circuits Syst. II Express Briefs.

[10]  B. Nauta,et al.  Wide-band CMOS low-noise amplifier exploiting thermal noise canceling , 2004, IEEE Journal of Solid-State Circuits.

[11]  Jose Silva-Martinez,et al.  A robust feedforward compensation scheme for multistage operational transconductance amplifiers with no Miller capacitors , 2003, IEEE J. Solid State Circuits.

[12]  Namsoo Kim,et al.  A 1.8 dB NF Blocker-Filtering Noise-Canceling Wideband Receiver With Shared TIA in 40 nm CMOS , 2014, IEEE Journal of Solid-State Circuits.

[13]  Peter R. Kinget,et al.  A Switched-Capacitor RF Front End With Embedded Programmable High-Order Filtering , 2016, IEEE Journal of Solid-State Circuits.

[14]  Lawrence E. Larson,et al.  An Active Transmitter Leakage Suppression Technique for CMOS SAW-Less CDMA Receivers , 2010, IEEE Journal of Solid-State Circuits.

[15]  Rinaldo Castello,et al.  A 15 mW, 70 kHz 1/f corner direct conversion CMOS receiver , 2003, Proceedings of the IEEE 2003 Custom Integrated Circuits Conference, 2003..

[16]  N. A. Moseley,et al.  Digitally Enhanced Software-Defined Radio Receiver Robust to Out-of-Band Interference , 2009, IEEE Journal of Solid-State Circuits.

[17]  Xiaodong Liu,et al.  A 65 nm CMOS Wideband Radio Receiver With $\Delta \Sigma $-Based A/D-Converting Channel-Select Filters , 2016, IEEE Journal of Solid-State Circuits.

[18]  Namsoo Kim,et al.  A highly linear SAW-less CMOS receiver using a mixer with embedded Tx filtering for CDMA , 2008, 2008 IEEE Custom Integrated Circuits Conference.

[19]  Kari Stadius,et al.  A 2.5-GHz Receiver Front-End With $Q$-Boosted Post-LNA $N$-Path Filtering in 40-nm CMOS , 2014, IEEE Transactions on Microwave Theory and Techniques.

[20]  Alyosha C. Molnar,et al.  A Passive Mixer-First Receiver With Digitally Controlled and Widely Tunable RF Interface , 2010, IEEE Journal of Solid-State Circuits.

[21]  Ahmad Mirzaei,et al.  Analysis and Optimization of Direct-Conversion Receivers With 25% Duty-Cycle Current-Driven Passive Mixers , 2010, IEEE Transactions on Circuits and Systems I: Regular Papers.

[22]  Henrik Sjöland,et al.  A Compensation Technique for Two-Stage Differential OTAs , 2014, IEEE Transactions on Circuits and Systems II: Express Briefs.

[23]  Sudhakar Pamarti,et al.  26.6 A programmable receiver front-end achieving >17dBm IIP3 at <1.25×BW frequency offset , 2016, 2016 IEEE International Solid-State Circuits Conference (ISSCC).

[24]  Henrik Sjoland,et al.  A cellular receiver front-end with blocker sensing , 2016, 2016 IEEE Radio Frequency Integrated Circuits Symposium (RFIC).

[25]  Eric A. M. Klumperink,et al.  A 0.2-to-2.0GHz 65nm CMOS receiver without LNA achieving ≫11dBm IIP3 and ≪6.5 dB NF , 2009, 2009 IEEE International Solid-State Circuits Conference - Digest of Technical Papers.

[26]  Ahmad Mirzaei,et al.  A Blocker-Tolerant, Noise-Cancelling Receiver Suitable for Wideband Wireless Applications , 2012, IEEE Journal of Solid-State Circuits.

[27]  Bram Nauta,et al.  A mixer-first receiver with enhanced selectivity by capacitive positive feedback achieving +39dBm IIP3 and <3dB noise figure for SAW-less LTE Radio , 2017, 2017 IEEE Radio Frequency Integrated Circuits Symposium (RFIC).