RFIC – Atlanta June 15-17, 2008 RTU1A-5 A 25 GHz 3.3 dB NF Low Noise Amplifier based upon Slow Wave Transmission Lines and the 0.18 μm CMOS Technology A. Sayag (1), S. Levin (2), D. Regev (2), D. Zfira (2), S. Shapira (2), D. Goren (3) and D. Ritter (1) (1) Department of Electrical Engineering, Technion, Haifa, Israel (2) Tower Semiconductors inc., Migdal HaEmek, Israel (3) IBM Haifa Research Laboratories, Haifa, Israel

RFIC – Atlanta June 15-17, 2008 Outline Low Noise Amplifier design methodology New semi-analytic model for slow wave transmission lines LNA performance

RFIC – Atlanta June 15-17, 2008 Motivation Can we get close to the transistor minimum NF in 24GHz LNA design? Best 0.18 μm 24 GHz LNA: NF=3.9 [Shih-Chieh Shin et al., IEEE MWCL, 24GHz

RFIC – Atlanta June 15-17, 2008 LNA Design Methodology 1.Determine the optimal current density 2.Determine critical circuit element values 3.Choose the transistor width

RFIC – Atlanta June 15-17, 2008 Transistor Performance Determined by Current 24GHz

RFIC – Atlanta June 15-17, 2008 Transistor Performance Determined by Current Density

RFIC – Atlanta June 15-17, 2008 Circuit Topology: Common source with inductive source degeneration

RFIC – Atlanta June 15-17, 2008 Source Inductor value for each Width

RFIC – Atlanta June 15-17, 2008 Example: Source Inductor for W=40μm

RFIC – Atlanta June 15-17, 2008 How does the Insertion Loss of the Input Matching Network Depend on Transistor Width? Equal Insertion loss contours Each point on the Smith Chart corresponds to a hypothetical transistor input impedance Input impedance is matched to 50 ohms by a matching network with inductors having Q=20

RFIC – Atlanta June 15-17, 2008 Insertion Loss Map of the Input Matching Network with Q = 10

RFIC – Atlanta June 15-17, 2008 Insertion Loss Map of the Input Matching Network with Q = 30

RFIC – Atlanta June 15-17, 2008 We need Q > 20 !

RFIC – Atlanta June 15-17, 2008 Choosing the Transistor Widths (assuming a two identical stage amplifier ) NF total [dB]gs [dB]Min NF [dB] Transistor Max Gain [dB] W [um] * g S - normalized source gain factor

RFIC – Atlanta June 15-17, 2008 Choosing the Transistor Widths (assuming a two identical stage amplifier ) NF total [dB]gs [dB]Min NF [dB]Max Gain [dB]W [um]

RFIC – Atlanta June 15-17, 2008 High Q Slow Wave Transmission Lines Effective dielectric constant larger than that of the surrounding dielectric material The effective dielectric constant determined by geometry

RFIC – Atlanta June 15-17, 2008 Properties of Slow Wave TL Isolation from the lossy silicon substrate Shorter wavelength  shorter matching networks Lower loss per wave length  higher Q of resonators Smaller die area Higher characteristic impedance Complicated EM simulations Complicated layout

RFIC – Atlanta June 15-17, 2008 Measured and Simulated Slow Wave Transmission Line Parameters twice the effective dielectric cons. of SiO 2

RFIC – Atlanta June 15-17, 2008 Properties of Slow Wave Transmission Line

RFIC – Atlanta June 15-17, 2008 Our Compact Analytic RLCG Model of Slow Wave Transmission Lines *A. Sayag et al., submitted to TMTT

RFIC – Atlanta June 15-17, 2008 Using our Compact Model to predict Slow wave TL performance

RFIC – Atlanta June 15-17, 2008 Low Noise Amplifier All the matching networks are slow wave transmission lines

RFIC – Atlanta June 15-17, 2008 Measured and Simulated Performance

RFIC – Atlanta June 15-17, 2008 Simulated Noise Contributions Transistors: 70% Transmissions lines: 23% Capacitor parasitics: 7%

RFIC – Atlanta June 15-17, 2008 Comparison with State of the Art LNAs [1]Shih-ChiehShin et al., IEEE Microwave and Wireless Component Letters, July, [2]E. Adabi et al., " RFIC Symposium, June 3-5, 2007, Honolulu, Hawaii.

RFIC – Atlanta June 15-17, 2008 Conclusions LNA design methodology presented. New analytic model of slow wave transmission lines. Record 2.8dB 24 GHz obtained using 0.18 μm technology. Slow wave transmission lines contributed only 23% of the total noise. Lower NF should be achieved using more advanced technologies

RFIC – Atlanta June 15-17, 2008 Thank You!

RFIC – Atlanta June 15-17, 2008 Testing our model: Comparison between Slow Wave Transmission Line and Grounded Coplanar Waveguide Grounded coplanar Slow wave

RFIC – Atlanta June 15-17, 2008 Comparison of Slow Wave and Grounded Coplanar Waveguide

RFIC – Atlanta June 15-17, 2008 Comparison between Slow Wave Transmission Line and Coplanar Waveguide Coplanar Waveguide slow wave

RFIC – Atlanta June 15-17, 2008 Comparison between Slow Wave and Coplanar Waveguide