Paper presentation Ultra-Portable Devices Paper: F Bruccoleri, E - PowerPoint PPT Presentation

Paper presentation – Ultra-Portable Devices Paper: F Bruccoleri, E Klumperink, B Nauta ”Generating All Two -MOS-Transistor Amplifiers Leads to New Wide- Band LNAs” Journal of Solid State Circuits, vol. 36, no. 7, pp. 1032- 1040, july 2001. Presented by: Carl Bryant 2010-02-22 Paper Presentation - Ultra Portable Devices 1

Outline • Introduction • Systematic approach • Generate combinations • Parameter analysis • Amplifier selection • Amplifier analysis • LNA 2010-02-22 Paper Presentation - Ultra Portable Devices 2

Introduction • Design wideband LNA • UWB requires inductorless design • Should present real impedance • Should have gain • Should have low noise • Idea: • Systematic design • Explore all combinations of two transistors 2010-02-22 Paper Presentation - Ultra Portable Devices 3

Systematic approach • Generate all two device combinations – MOS devices represented as voltage controlled current source (vccs) – Combined devices represented using two-port representation • Select potentially useful amplifiers • Examine amplifiers 2010-02-22 Paper Presentation - Ultra Portable Devices 4

Generate combinations • Create two-port represented by ABCD parameters i 1 i 2 + + Two-port v 1 v 2 network - -       A B v v  1 2              i C D i   1 2 2010-02-22 Paper Presentation - Ultra Portable Devices 5

Parameter analysis • Potentially useful – Has forward gain – Presents real input impedance – Wideband (> one decade) – Stable 2010-02-22 Paper Presentation - Ultra Portable Devices 6

Parameter analysis • Find constraints • Study Z IN and A VF as function of Z L and ABCD parameters – Z IN & A VF different from {0,  } – At least two parameters nonzero 2010-02-22 Paper Presentation - Ultra Portable Devices 7

Parameter analysis • Non-zero parameter combinations – Example: AD represents { A ,0,0, D } • Assume Z L = 1/j ω C L • {AD} and {BC} cases too frequency dependent • {BD} and {BCD} show frequency dependent gain • {ABD} cannot provide simultaneous wideband match and gain 2010-02-22 Paper Presentation - Ultra Portable Devices 8

Parameter analysis • Sought two-ports contained in: {AC, ABC, ACD, ABCD} • Want unconditional stability •  ( Z IN )  0,  ( Z 22 )  0 assuming Z 11 = Z IN • Neccesary and sufficient { A,B,C,D } have same sign 2010-02-22 Paper Presentation - Ultra Portable Devices 9

Amplifier selection • Implementable with MOS devices – Only select circuits where vccs form three terminal devices – Of 145 2VCCS combinations 19 remain – Correspond to {ACD, ABC, ABCD} cases • One {ABC} and three {ABCD} fulfill all requirements 2010-02-22 Paper Presentation - Ultra Portable Devices 10

Amplifier analysis Z IN Z OUT A A VF VR Amp1 1/g a 1/g b 1+g a /g b 0 Amp2 1/g a 1/g a -g a /g b g b R S Amp3 1/g a (R b +R S )/(1+g a R S ) 1-g a R b g b R S /(g a R S +1) Amp4 1/g a R b g a R b 0 No comment NEF = Noise Excess Factor (related to  ) 2010-02-22 Paper Presentation - Ultra Portable Devices 11

Amplifier analysis 2010-02-22 Paper Presentation - Ultra Portable Devices 12

Amplifier analysis • Amp 1: • NF independent of gain • VCCS a noise cancelled 2010-02-22 Paper Presentation - Ultra Portable Devices 13

LNA • Based on Amp1 • Variable gain by changing g b 2010-02-22 Paper Presentation - Ultra Portable Devices 14

LNA Performance Summary Vdd 3.3V Idd 1.5 mA 0.35 μ m Tech. A VF 11 dB -3dB BW 50-900 MHz CP 1dB -6 dBm IIP 3 14.7 dBm NF <4.9 dB 75 Ω R S 2010-02-22 Paper Presentation - Ultra Portable Devices 15

Summary • Systematic design of compound amplifier stage • Result is new LNA structure • Promising noise & linearity • 2dB better NF than comparitive CG amplifier • Low current consumtion for 0.35 μ m design – Scales to 375 μ A @ 300 Ω • Such a stage used in december tape-out 2010-02-22 Paper Presentation - Ultra Portable Devices 16