1. Differential Active Inductor 2. Switched Bandpass ... · Active inductor size (picture): 200 µm...

1Universität StuttgartInstitut für Elektrische und Optische Nachrichtentechnik Professor Dr.-Ing. Manfred Berroth

MOS-AK Meeting 2002, Xfab, Erfurt, Germany

21.10. 2002, © Markus Grözing

Markus Grözing, Manfred Berroth

Institut für Elektrische und Optische NachrichtentechnikUniversität Stuttgart

1. Differential Active Inductor2. Switched Bandpass Amplifier3. Broadband Oscillator




• Technology: 0,25 µm CMOS• Supply voltage: 2,5 V• Frequency range: DC to 5 GHz

• Status: processed and measured




Active Inductor MotivationI. Avoid spiral inductors

– require large die area– potential magnetic field coupling– layout cells and models often not available in

standard-CMOS foundry design kits– fixed L value single-band operation– fixed and low Q value on standard, low resistive

CMOS substrates

II. Achieve multi-band operation– tuned L value– switched L value




Circuit Concept

Transforms intrinsic capacitances to inductive behaviour

Common mode and even harmonic rejection

Broadband negative resistors available

2

2m

1

1mo

2m1m

2

'CG

'CG

LC21f

GG'CL

=π

=

=

Differential Gyrator Topology

Gm1

Gm2

UIN

IIN

C'2C'1




Circuit Implementation (RF)

2 IL

2 IL 2 IQ1

2 IQ2

IL+IQ1

IL+IQ2

UDD

UDD

UIN

IIN

Gm1

Gm2 Transconductance

Stage 2

Transconductance Stage 1

Negative Resistance Loads

Reference [1]




Circuit Implementation (DC)

Current Mirrors

U INIIN

D1 D1'

P1P1'

N1

D2 D2'

P2 P2'

N2

U2

DNR2 DNR2'

NNR2

DNR2 DNR2'

NNR2

UDD

ILref IQ1ref

IQ2ref

NNRrefNref

Nref NNRref

Pref

Pref

Nref NNRref

NNRref

CLCQ1

CQ2

CP

RLRQ1

RQ2

Adding Current Mirrors

L-Tuning Q-Tuning

Reference [2]




Small Signal Model

C2C1

C1 C2g2

g2g1

g1

Cgd1

Cgd2

Cgd1

gm1(-U2')gm1( U2')

gm2( U1')

gm2(-U1')

U2'

-U2'

U1'

-U1'

UIN = U1U2

IIN

C1 C2g2g1

C12

gm1U2' gm2U1'U2'

1/2 UIN = U1'

IIN

IIN

UIN

( )[ ][ ] ( ) ( ) ( )[ ] ( )( )[ ]2

121221212

12121221121m2m212m1m

1222

1

1

IN

ININ

CCCCCsCCgCCgCggsggggCCsg2

I'U2

IUZ

−+++++++−++++

===

121

121

2m1m

2

2m1m

2

gG

CCggg2R

ggC2L

≈

≈

≈

≈

3 Simplified circuit1 Differential mode equivalent circuit of the active inductor

2 Differential mode equivalent circuit of half the active inductor




Tuning and Scaling of Inductance LTuning Scaling

MOSFETs size:

Eq. circuit elements:

Inductance:

Power- / current consumption:

Noise:

Saturation current:

Dynamic range:Lo

mDomm

o

L

mDmm

LLox

mD

If

gfCCggf

IL

gL

ggCL

ionapproximatchannellong

IILWCg

~ frequency Resonant

~21

1~ Inductance

1~2

)(

~2

21

21

221

2

→=

→=

−−

=

π

µaltneu WMW ⋅=

M~g,g,C,C 2m1m21

M1~L

M~I,P DCDC

M~Ineff

M~IINsat

M~M

M~f)f(I

IDRneff

max/INsat

∆⋅=




Layout

GND

GND

GND

GND GND GND

GND GND

GND

IL

IQ1 IQ2 UDD GND

RF+ RF-

Chip size: 1300 µm x 700 µmActive inductor size (picture): 200 µm x 200 µm




Measurement Setup

Problems:• measurement and calibration require

matched paths RF+ and RF- (red lines)• hybrid bandwidth is limited: 30 MHz to 3 GHz

ILref IQ2ref IQ1ref2,5 V

SMU 2 SMU 1 SMU 3 SMU 4 Port 1Differential-Mode-Response

Parameter-Analyzer (Biasing)

On-WaferProbe Station

Network-Analyzer

RF+

RF-

∆

Σ

180°-Hybrid

DC-Block

Port 2Common-Mode-Response




Measurement and Simulation Results

-j0.2

-j0.5

-j1

-j2

0.2 0.5 1 2

j0.2

j0.5

j1

j2

0 0.2 0.5 1 2

j0.2

-j0.2

j0.5

-j0.5

j1

-j1

j2

-j2

00

800

2000 Current IQ2ref [µA]

00 Current IQ1ref [µA]

800 Current ILref [µA]

Symbol simulation

Symbol measurement

3,2Inductance L [nH]

Differential reflection coefficient Γ IN

f = 200 MHz to 3 GHzZ0 = 100 Ω

100

11,70Current IQ2ref [µA]

10,70 Current IQ1ref [µA]

100 Current ILref [µA]

Symbol simulation

Symbol measurement

23Inductance L [nH]




Differential Active Inductor SUMMARY

1,9simulated: 5,6 Resonant frequency fo GHz23 3,2 Inductance L [nH]

4,73 32,0 Power consumption PDC [mW]1,89 12,8 Current consumption IDC [mA]11,7200Current IQ2ref [µA]10,70Current IQ1ref [µA]100 800 Current ILref [µA]

Advantages:tunable inductance value Ltunable quality factor Qhigh frequency operation

Disadvantages:DC power consumptionlimited large signal performance (determined by DC)poor noise performance




• Technology: 0,18 µm CMOS• Supply voltage: 1,8 V• Bandpass frequencies:

Version 1: 100 MHz and 1 GHz (2 BP-frequencies)Version 2: 125 MHz to 875 MHz (7 BP-frequencies)

• StatusVersion 1: currently manufacturedVersion 2: development




Bandpass Amplifier Motivation

SwitchedBandpassAmplifier

f

S1(f)

50MHz 1GHz

Zin=75Ω

VCO

f

H(f)

f

1f

S4(f)

f

S2(f)

f

S3(f)

160MHz

ARDARD ARD ARD

Uin

Mixer Lowpass Filter

160MHz

fBP

Cable modem: reduce amplifier bandwidthrelax mixer and filter linearity requirementsreduce power consumption




Circuit Concept (Version 1)Large signal requirements:

tuning of inductance not applicableswitched inductance circuit concept

Zin=75 Ω

Differential Common-Gate

Amplifier

GmV.Uin RL

C1=C1,ext+Cp1+Cp2

L1

Uin Uout

C21=C1,ext+Cp2+Cp1

GmL1

Active Inductor L2

C22=C1,ext+Cp1+Cp2

GmL2

L2 Active Inductor L1

Switch

C22,ext

C21,ext

Reference [3]




Circuit Implementation (Version 1)Negative

ConductanceTransconductance

AmplifiersIn IpUDD

IL

On/Off

Pref,1

P1 P1

Nref

N1 N1

N2 N2

Nref

Pref,2P2 P2

D2 D2

D1 D1

NNR1 NNR1

NNR1,ref

NNR2 NNR2

NNR2,ref

DNR2

DNR2

DNR1

DNR1

C2i

L2

L2

L1

L1

LNR1

LNR1

LNR2

LNR2M M

IQ1

IQ2

Active inductors with source-degenerated differential amplifiersto enhance large signal performance

Reference [4]




Noise figure @ 75 Ω

Current consumption

Input 1dB-commpression point*)

Bandwidth

Voltage gain

Input impedance

Bandpass frequency

F75

IDC

Uin,1dB

B

VU

Zin

fBP

15,8 dB 8,7 dB

46,8 mA 9 mA

83 mV 127 mV

180 MHz 160 MHz

16,09 dB 16,15 dB

(69 - j 20)Ω(75 - j 2)Ω

993 MHz 97 MHz

Simulation Results (Version 1)

*) voltage amplitude




Simulation Results (Version 2)




• Technology: 0,18 µm CMOS• Supply voltage: 2,0 V• Frequency range: 1 GHz to 3,5 GHz• Status: currently manufactured




Broadband Oscillator MotivationLocal Oscillator for

• Multi-bitrate serial transceiversi.e. 1.0, 1.25, 2.0, 2.5, and 3.125 Gbit/s

• Broadband tuners i.e. cable modem

• Multi-band wireless transceivers




Circuit Design

OscillatorCore

UDD

USS

UDD

USS

UDD

USS

UDD

USS

RF 0

RF 180

RF 90

RF 270

50 Ω

50 Ω

50 Ω

50 Ω

HF 0

HF 180

HF 90

HF 270

U/V

t/ns92 94 96 98 100

0

1

2

U/V

t/ns92 94 96 98 100

0

1

2

U/V

t/ns92 94 96 98 100

0

1

2

t/ns92 94 96 98 100

0

1

-1

U/V

signal HF 0 inoscillator core

signal aftersecond inverter

signal at 50 Ω load




Simulation Results

0,78 V44 µA19 mA-94,6394,3 MHz5,0 µA0,378 V0,98 V0,6 mA34 mA-93,41725 MHz75,3 µA0,500 V1,03 V0,9 mA35 mA-91,691,00 GHz116 µA0,525 V1,22 V2,4 mA38 mA-86,852,07 GHz320 µA0,600 V1,46 V4,6 mA43 mA-83,393,14 GHz663 µA0,678 V1,71 V7,6 mA48 mA-81,144,07 GHz3,21 mA1,000 V1,77 V8,4 mA50 mA-80,864,29 GHz17,5 mA2,000 V

UcoreIDCcoreIDCPN [dBc/Hz]

foszISteuerUSteuer

Corevoltage swing

CoreDC-

current

OverallDC-

current **)

Phase -noise *)

@ 1 MHz

Oscillation frequency

Equivalentcontrol current

Controlvoltage

*) phase noise simulation was done with a voltage source applied to the control input USteuer**) overall current consumption is mainly due to the four inverter chain line drivers




CONCLUSIONActive inductor based circuits offer…

Advantages:• broadband operation (tuned L)• multiband operation (switched L)• small chip area• quadrature outputs (VCO)

Drawbacks:• DC power consumption• limited large signal performance• poor noise performance




[1] Thanachayanont, Apinunt and Payne, Alison: “CMOS floating active inductor and its applications to bandpass filter and oscillator designs”,IEE Proceedings Circuits, Devices and Systems, Special issue on High-frequency integrated analogue filters, Vol. 147, No. 1, February 2000

[2] Grözing, Markus; Pascht, Andreas; Berroth, Manfred:“A 2.5 V CMOS Differential Active Inductor with Tunable L and Q for Frequencies up to 5 GHz”,2001 IEEE Radio Frequency Integrated Circuits (RFIC) Symposium, Phoenix, Arizona, May 20-22, 20012001 RFIC Digest of Papers, pp 271-2742001 International Microwave Symposium Digest, Vol. 1, pp 575-578

[3] Akbari-Dilmaghani, Rahim and Payne, Alison: “An RF CMOS Differential Bandpass Amplifier using an Active Inductor”, IEE Colloquium on Systems on a Chip (Ref. No. 1998/439), London, UK, pp. 16/1-6, 1998

[4] Krummenacher, Francois and Joehl, Norbert: “A 4-MHz CMOS Continious-Time Filter with On-Chip Automatic Tuning”, IEEE Journal of Solid-State Circuits, Vol. 23, No. 3, June 1988

Literature




The authors would like to thank

Harald Parzhuberand

Johannes Gerber,Hermann Mayerhofer

Texas Instruments Deutschland GmbHFreising

for providing us with processing capabilities and

for help with the layouts and final design checks

Acknowledgment

1. Differential Active Inductor 2. Switched Bandpass ... · Active inductor size (picture): 200 µm...

Documents

Transcript of 1. Differential Active Inductor 2. Switched Bandpass ... · Active inductor size (picture): 200 µm...