A>40dB IRR, 44% Fractional-Bandwidth Ultra-Wideband mm-wave Quadrature LO Generator for 5G Networks in 55nm CMOS

Transcription

1 A>40dB I, 44% Fractional-Bandwidth Ultra-Wideband mm-wave Quadrature LO Generator for 5G Networks in 55nm MOS F. Piri 1, M. Bassi 1,2, N. Lacaita 1,2, A. Mazzanti 1, F. Svelto 1 1 University of Pavia, Pavia, Italy 2 now with Infineon Technologies, Villach, Austria

2 Outline Motivations Quadrature Generation in Poly-Phase Filters Proposed Quadrature Generation Architecture Measurement esults onclusion 2

3 Wideband equirements in 5G [S. Hu, ISS 2017] ombining bands around 28GHz, 37GHz and 39GHz carriers is key for international roaming and intra-networks connections A Quadrature LO with a challenging I>40dB over >40% bandwidth is required 3

4 In p Mm-Wave IQ Generation QVOs show strong trade-off between phase noise and phase accuracy Lange and Hybrid ouplers disregarded because of large footprint, sensitivity to k variations + I p - In n + Q p - 3-Stage PPF PPFs can achieve I>40 with fractional bandwidth > 40%, but more than 3 stages are necessary TYPE-A PPF ( Amp =0) 4 I Amp2 + 2 ) ( Amp <<1) θ Desired BW 4

5 IQ Phase alibration Loop Vtune1 Vtune2 Vtune3 f in =31GHz f in =36GHz f in =42GHz Single-stage constant amplitude PPF for low loss alibration loop continuously tunes PPF center frequency to minimize phase error For I > 40dB with margin, phase error must be well below < 1 5

6 omplete Block Diagram I p I BB V IN 1 Stage Tunable Polyphase Filter Buff Vdd Phase Detector I n V OUT Buff Vdd Vtune Amp I p I n Q p Q n Q p Buff Vdd LO buffer based on cross coupled pairs to enhance gain and stability Output quadrature mixer for measurement purposes Q n Measurement Mixer Q BB 6

7 Magnetically oupled esonators Interfaces I in 2 Buff in k i o r o PPF Buff out I p k o Q p i r i I out I in 2 o r o k i I n Q n k o i r i Q out The overall transfer function must show a > 50% fractional BW. Once i and o are resonated out an optimum (PPF resistance) exist in transfer function maximizing gain for the given BW. For design parameters o 2 i 40f and r i 4r o 800Ω =40f and =110 Ω. 7

8 lassic PPF Layout: L par issue I p In p Q p In n L par I n Q n I n Q p Q n I p Long inductive connection L par causes differential phase mismatch on I p /I n. Differential I p /I n error of results in Quadrature I/Q error of. 8

9 Proposed PPF symmetric Layout Q p 2 Q P In p 2 Q n In P Qn In n I n Inn 1 I P 1 I p In V tune Improved layout with symmetrical I-Q paths to leave out effect of Lpar and differential inaccuracy effects on following stages. 9

10 hip Photo and Power Break-Down Buffer PPF Q Buffer IBuffer Meas. Mix PD Mix ealized with 55nm MOS technology by STM Full chip area 2.3 x 1.7 mm 2 ore area 590 x 330 µm 2 Power onsumption including in/out LO buffers 36mW and 3mW for alibration loop. 10

11 Measurement Setup VSG E8257D D Board Digital interface Baseband Q PSG E8257D 26-46GHz LO Signal PXA N9030A Baseband I hip is tested with GSG probes Additional board with D biases and level translators for digital interface 11

12 I and Spectrum spurs Settings : f LO = 36 GHz P LO = +6 dbm f BB = 0.5 MHz P BB = -29 dbm I=43dB LO Leakage= -23dBc (able loss not deembedded) 12

13 Measurement esults Loop ON : I>40dB from GHz (44% fractional BW) Loop OFF: Vtune manually set Phase -130 dbc/hz. No penalty in PN introduced by the IQ generator circuit 13

14 Performance Summary and omparison S. Kulkarni TASII 2013 [3] T. Zhang ESSI 2015 L. Wu JSS 2013 J. S. Park TMTT 2015 [2] S. P. Sah TMTT 2013 [4] K. J. Koh JSS 2007 [5] Q. Shi A-SS 2013 This Work Process 40nm MOS 28nm MOS 65nm MOS 65nm MOS 180nm BiMOS 130nm MOS 40nm MOS 55nm MOS BW [GHz] Fractional BW [%] I [db] D Power [mw] Area [µm 2 ] >35 N/A 65 x >32 N/A 20 x >33 ore 50mW alibration Loop 35mW The best I (>40dB) beyond 20GHz over large (44%) fractional BW x >40 N/A 772 x >17 N/A 370 x >13 N/A ~160 x >25 N/A 120 x >40 PFF + in/out buffers 36mW alibration Loop 3mW 590 x 330 (ore) 2300 x

15 onclusions 5G communication systems require high purity local oscillators Providing wideband quadrature LO signal with good I is challenging A single-stage low-loss PPF stage in combination with a calibration loop is proposed to achieve both wide bandwidth, low loss and high I Measurements on several samples show an I > 40dB over a fractional bandwidth larger than 44% 15