Paper presentation Ultra-Portable Devices Paper: Wang S.B.T, - PowerPoint PPT Presentation

Paper presentation – Ultra-Portable Devices Paper: Wang S.B.T, Nikejad A.M, et al. Design of a Sub-mW 960-MHz UWB CMOS LNA. Journal of Solid-State Circuits, vol.41, no.11, pp.2449- 2456, Nov. 2006. Presented by: Carl Bryant 2009-11-30 Paper Presentation - Ultra Portable Devices 1

Outline • Introduction • UWB circuits • Hybrid LNA • Results • Summary 2009-11-30 Paper Presentation - Ultra Portable Devices 2

Introduction • UWB LNA • Low power • Differential • UWB → Inductorless • Intended for UWB (pulsed) radio 2009-11-30 Paper Presentation - Ultra Portable Devices 3

Introduction • In UWB system most noise is from interference • Very low LNA noise figure not important • Most interference power is already in-band • Thus folding interferance into band not a great concern • i.e. IIP3 spec not very important either • Goal is instead to minimize power consumption for moderate NF and linearity 2009-11-30 Paper Presentation - Ultra Portable Devices 4

UWB circuits • Inductorless matching • (a) Resistor terminated CS (R-CS) • (b) Shunt feedback (SFB) • (c) Common gate (CG) 2009-12-01 Paper Presentation - Ultra Portable Devices 5

UWB circuits • Resistor terminated – Lowest possible power consumption – High noise figure – NF<6dB → gm > 25mA/V • CG and SFB – NF<6dB → g m > 5mA/V – Z in =50 Ω → g m > 20mA/V • Differential amplifier – Input voltage halved on each side – Same Zin → Double power consumption 2009-11-30 Paper Presentation - Ultra Portable Devices 6

UWB circuits 2009-12-01 Paper Presentation - Ultra Portable Devices 7

UWB circuits • Complementary SFB and CG amplifier stages • More g m for the same current (but slower) 2009-12-01 Paper Presentation - Ultra Portable Devices 8

Hybrid LNA • Cross coupled stages act as both SFB and CG amplifier stages • SFB is inverting, CG is non-inverting • Effectively doubles V gs swing 2009-11-30 Paper Presentation - Ultra Portable Devices 9

Hybrid LNA • Small signal analysis 2009-11-30 Paper Presentation - Ultra Portable Devices 10

        1  f A 4 g R 1   3 dB V , DC m f 2 R r C C f 0 gd gs  1 Z 4 g in m  R 1 8    S   F 1   2 g g R R m , N m , P S f       g g 1 4 R F 1  m , N m , P S • Both NMOS and PMOS contribute gain • Noise figure much like CG or SFB amplifier 2009-11-30 Paper Presentation - Ultra Portable Devices 11

Hybrid LNA • LNA with output buffer • Additional cross coupling of bulks for extra gain (5-15%) 2009-11-30 Paper Presentation - Ultra Portable Devices 12

Results 2009-11-30 Paper Presentation - Ultra Portable Devices 13

Results 0.13 μ m CMOS Technology BW 100-930 MHz Gain 13 dB NF 4 dB IIP3 -10.2 dB CP1dB -18 dBm Power 0.7 mA @ 1.2V 2009-11-30 Paper Presentation - Ultra Portable Devices 14

Summary • Design of differential inductorless LNA • Low power consumption makes gain and matching difficult • Use complementary devices and cross couplings • 0.7mA with Z in =50 Ω 2009-11-30 Paper Presentation - Ultra Portable Devices 15

Chip photo 2009-11-30 Paper Presentation - Ultra Portable Devices 16