A 0.98 to 6.6 GHz Tunable Wideband VCOin a 180 nm CMOS Technology

for Reconfigurable Radio TransceiverYusaku Ito, Hirotaka Sugawara, Kenichi Okada, and Kazuya MasuIntegrated Research Institute, Tokyo Institute of Technology, Japan

Conclusion

ImpactMeasurement results

0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8Varactor control voltage [V]

Osc

illat

ion

frequ

ency

[GH

z]

7.0

6.5

6.0

5.5

5.0

4.5

4.0

3.5

3.0

2.5

2.0

1.5

1.0

0.5

2 fo

3/2 fo

fo

3/4 fo

1/2 fo Normalizing VCO phase noise (L{foffset}) by center frequency (fo),power consumption (Pdc) and frequency tuning range (FTR).

FOMT

−=

+

⋅−=

1020

110

1020 FTRFOM

mWPFTR

fffLHzdBcFOM DC

offset

ooffsetT logloglog}{]/[

1mW

−=

+

⋅−=

1020

110

1020 FTRFOM

mWPFTR

fffLHzdBcFOM DC

offset

ooffsetT logloglog}{]/[

1mW

The proposed wideband LC-VCO achieves the widest tuning range,and the best FOMT simultaneously using pure CMOS technology.

-60

-30

-40

-50Pow

er [d

Bm

]

Freq. [Hz]

IMR

R =

20.

2 dB

Vgain A = 1.36 V

-35.5 dBm(1.36 V)

-37.5 dBm(1.32 V)-36.5 dBm(1.34 V)

-39.0 dBm(1.28 V)

-55.7 dBm

Vgain A = 1.34 V-48.7 dBm

Vgain A = 1.32 V -43.7 dBm

Vgain A = 1.28 V -40.7 dBm

Rejection

3/2fo (2.93 GHz)1/2fo (0.98 GHz)

Phase noise

Tuning range Spurious rejection (the combiner output)

Detail of proposed VCOBackground

-210

-200

-190

-180

-170

-160

-150

-140

-130

0 20 40 60 80 100 120 140 1600

-200dBc/Hz

-190dBc/Hz

-180dBc/Hz

-170dBc/Hz

-160dBc/HzFOMt =

FTR [%]

FOM

[dB

c/H

z]

Our previous work(A-SSCC 2005)

Better performance

Pure CMOS TechnologyCMOS with MEMS SOI CMOS BiCMOS SiGe-BiCMOS

×

×

This work

10k 100k 1M 10MOffset frequency [Hz]

-40

-60

-80

-100

-120

-140

-160

Pha

se n

oise

[dB

c/H

z]

1.85 GHz (3/4fo)

2.50 GHz (fo)

5.13 GHz (2 fo)

3.40 GHz (3/2 fo)

1.13 GHz (1/2 fo)

1/2Div

DifferentialVCO

Divider DSBM DividerSwitchfo 1/2

Divfo

fo

fo

fo or 1/2fo

1/2fo and 3/2foDC and 2fo

2fo

Reject spur

A A A

B

B B

SVin_1

SVin_2

SVout = ASVin_1+BSVin_2

Gain Control

ASVin_1 BSVin_2 SVout

1/2fo 1/2fo 3/2fo 3/4fo

1/2fo

180

1/2fo 3/2fo

0

3/2fo

+ =

AS

witc

h tu

rn to

Variable GainCombiner

Variable GainCombiner

⇒

TSMC 0.18 µm CMOS process with RF option

Supply voltage :

Total current :

1.8 V2.45 ～ 14.9 mA

FTR = 149 %

FOM = - 202 ～ - 206 [dBc/Hz]

T

Reconfigurable Analog RF Circuit

PA

LNA

LO

LPF DAC

PGA ADC

SW

I QFD LPF

1/NVCO

MIX

MIX LPF

PLL

Bas

eban

d LS

I

RF Front-end

- On-chip RF Transceiver with Direct-Conversion Architecture -

Mobile Communication Device･ More multi-band/mode functions･ Smaller size･ Lower power operation

A Multi-band RF front-end implementedin a single chip is required.

800MHz - 6GHz

A differential LC-VCO and a double side-band mixer and utilized instead of a QVCO and a SSMB .The proposed wideband VCO can achieve wide tuning range 0.98 - 6.64 GHz with sufficient phasenoise.

.

6.64 GHz

0.98 GHz

FTR = f - f

fcenter

max min

540 µm

800 µm

We use the Differential VCO instead of QVCO.We can achieve the wide tuning range and low phase noise with smaller layout area.

Tuning-range extension technique (Using LC-VCO, divider and mixer)It can achieve the wide tuning range with sufficient phase noise..

Wideband VCO is an indispensable component toachieve the multi-band RF front-end.

Purpose of this work