Hirotaka Sugawara, Yoshiaki Yoshihara, Kenichi Okada, and Kazuya Masu Precision and Intelligence Laboratory, Tokyo Institute of Technology, Japan Reconfigurable CMOS LNA for Software Defined Radio Using Variable Inductor Background Reconfigurable RF Circuit Multi-band RF front-end Architectures Conclusion Tunable LNA L1 50Ω 50Ω Vgs=0.65 V Vdd=1.8 V L2 L=0.2 μm W=5 μm m=60 L=0.2 μm W=5 μm m=60 Pin Pout Wireles s Standards n Mobile phone 900MHz, 1.5GHz, 2GHz (+ 800MHz, 1.7GHz, 1.9GHz for the new system) (+ 800MHz, 900MHz, 1.8GHz, 1.9GHz for GSM) n WLAN 802.11b/g, Bluetooth 2.4GHz n WLAN 802.11a/n 5GHz n GPS 1.2GHz/1.5GHz n DTV 470 MHz 770 MHz Purpos e PA LNA LO LPF DAC ADC SW RF Front-End I Q MIX MIX LPF Baseband LSI Proposed Concept To provide multiple functions to circuits Multi-function Reconfigurable RF Circuit Design K. Okada, et al., in ASP- DAC, Jan. 2005, pp.683-686. A multi-band/mode circuit for wireless communication chips Self-compensation Si CMOS Technology provide Wireless Communication Circuits Realiza tion of Si CMOS RF circuits Reconfigurable RF Circuit RF circuit is controlled by digital circuit Architectu re Proposed Archi tecture Variable Inductor Variable Inductor The inductance continuously varies depending on the position of the metal plate. The metal plate shields the magnetic flux which penetrate the inductor. h Spiral Inductor Metal Plate consists of a planar-type spiral inductor and a metal plate. MEMS Parallel Plate actuator V. M. Lubecke, and J. -C. Chiao: The IEEE 4 th Int. Conf. on Telecommunications in Modern Satellite, Cable and Broadcasting Services, 1999 p. 1 stationary electrode movable electrode Moving system is realized to use MEMS actuator Measu rement Turns : 3 Line width : 10 μm Line space : 1.2 μm Outer diameter : 300 μm 0.9 pF 0.6 pF 0.18 m m M5 CMOS Process 1.28 mm 0.97 mm Variable Characteri sti c 0 5 10 15 20 Frequency [GHz] PG [dB] -20 -10 20 10 @ 1.9 GHz PG=14.2 dB Pin=-27 dBm 0 0 5 10 15 20 Frequency [GHz] -100 -60 -20 -40 S12 [dB] @ 1.9 GHz PG=-31.0 dB Pin=-27 dBm -80 -30 -20 -10 0 5 Pin [dBm] -5 5 Pout [dBm] 0 -10 -15 0 5 10 15 20 Frequency [GHz] S22 [dB] S11 [dB] -20 -10 5 0 -5 S11 S22 S22 S11 1 2 3 4 5 Frequency [GHz] NF [dB] 10 4 8 6 @ 1.9 GHz NF=5.2 dB -15 -5 -15 -25 @ 1.9 GHz S11=-11.0 dB S22=-12.7 dB Pin=-27 dBm Freq.=1.9 GHz Input P1dB=-15.8 dBm 1.898 1.899 1.901 1.903 Frequency [GHz] Amplitude [dB] -140 1.900 1.902 -120 -80 -40 0 -60 -20 -100 -52.5 dBm @ 1.899 GHz -13.1 dBm @ 1.900 GHz -13.1 dBm @ 1.901 GHz -53.2 dBm @ 1.902 GHz Power= -27 dBm IIP3 =-7.2 dBm high density integration high frequency performance Low fabrication cost Wireless communication standards use several frequency bands. Multi standard Baseband Software Defined Radio (SDR) It is necessary for global roaming using SDR to realize Multi-band RF front-end 400 MHz-6 GHz To realize Multi-band RF front-end To provide a compensating mechanism Process variations, Modeling error, Temperature etc. Control Digital Circuit Proposed Tunable LNA Multi-band Down convertor Wide-band Antenna f Gain ... Tuning LNA Down convertor LNA Down convertor f ... Gain Using some signal paths for each frequency band It needs large chip area to extend the number of communication standards. Wide-band LNA Gain Multi-band Down convertor Wide-band Antenna f Distributed amplifier needs large chip area and power consumption. Using Distribute amplifier multi-band LNA using resonator Multi-band Down convertor Wide-band Antenna f Gain ... The approach require large chip area due to many resonators. Using some input resonators Wide-tunable CMOS LNA is realized by the variable inductor. The proposed LNA achieves wide-tuning range with narrow-band gain and can be used for reconfigurable RF front-end. Turns : 3 Line width : 20 μm Line space : 1.2 μm Outer diameter : 400 μm L 1 L 2 L 1 L 2 Q 4.5 3.5 3.0 4.0 @1.9 GHz Lmax/Lmin=1.5 Height of plate h [mm] 3 L [nH] 0 100 400 6 5 300 200 500 4 Q 4 3 2 Height of plate h [mm] 3 L [nH] 0 100 400 7 5 300 200 500 4 6 @1.9 GHz Lmax/Lmin=2.0 1 Frequency [GHz] 0.1 Q 4 3 2 1 10 0 Decrease in Metal Plate Height 1 Frequency [GHz] 0.1 L [nH] 4 2 10 0 10 8 6 Decrease in Metal Plate Height h=10 μm h=15 μm h=20 μm h=30 μm h=50 μm h=100 μm w/o Metal plate 1 Frequency [GHz] 0.1 Q 4 3 2 1 10 0 Decrease in Metal Plate Height 1 Frequency [GHz] 0.1 L [nH] 4 2 10 0 10 8 6 Decrease in Metal Plate Height L 1 L 2 h=10 μm h=15 μm h=20 μm h=30 μm h=50 μm h=100 μm w/o Metal plate Basic Characteristic Freq. [GHz] V dd [V] I dd [mA] PG [dB] S 22 [dB] S 11 [dB] NF [dB] IIP 3 [dBm] Input P 1dB [dBm] 1.9 1.8 7.4 14.2 -11.0 -12.7 5.2 -15.8 -7.2 V gs [V] 0.65 Summary of Performance 1 2 4 5 Frequency [GHz] PG [dB] 15 5 0 3 10 1 2 3 4 5 Frequency [GHz] NF [dB] 10 4 8 6 h=10 μm h=15 μm h=20 μm h=30 μm h=50 μm h=100 μm w/o Metal Plate Noise Figure (NF) : Shift to higher frequency as metal plate inserts Si CMOS Tunable LNA using the on-chip variable inductors for the SDR The variable ratios of the variable inductors are over 1.5. The proposed LNA achieves PG of over 10 dB from 1.6 GHz to 3.2 GHz. The minimum NF is shifted to higher frequency as inductances vary. This tunable LNA is quite useful for multi-band RF communication system with the reconfigurable RF circuit design. h Spiral Inductor Metal Plate Power Gain (PG) : 15 dB and over 10 dB from 1.6 GHz to 3.2 GHz. Decrease in Metal Plate Height Decrease in Metal Plate Height