5 Cmos Wide-band Low Noise Mixer - Copy

1 Presentation Outline

o Understand operating principles of the mixer

o Choices:

Nonlinear/switching mode; single/double balance;

active/passive

o Specify performance:

Gain, Noise Figure, P1dB, IIP3, isolation, image rejection

o Overview of my dissertation

o References

2 What is a mixer?

Frequency translation device

Doesn’t “mix”; it multiplies y(t)

x(t)y(t)x(t)

tAB

tAB

tytx )cos(2

)cos(2

)().( 2121

down convert up convert

Source :http://rf-circuits.info/radio/rf-mixers/

3Images

Two inputs (RF & Image) will mix to the same output (IF) frequency.

The image frequency must be removed by filtering

Image rejection ratio: dB(PIF desired/PIF image)


4

Mixer operating mechanisms Nonlinear transfer function

use device nonlinearities creatively!

useful at mm-wave frequencies

Switching or sampling

a time-varying process

preferred; fewer spurs

5 Nonlinear mixer operation

Any diode or transistor will exhibit nonlinearity in its transfer characteristic at

sufficiently high signal levels.


6 Switching or sampling mixers

Let

Multiply by the LO switching function T(t)

)cos()( tVtV RFRIN


7 Mixer Topologies :

Basic implementations:

― Passive mixers

― Active mixers

Mixers can be divided in classes, which all may be implemented as

passive or active:

― Single-device Mixer

―Single-Balanced Mixer

― Double-Balanced Mixer

8Active & Passive mixers :

Active Mixers:

Pros

― Small size

― High conversion gain

― Reduced power consumption

Cons

― More Noise Sources

― Less linear

Passive Mixers:

Pros

― More linearity

― High port to port isolation

― Low flicker noise

― Driven by both current as

well as voltage sources

Cons

― High power consumption

9 Singly Balanced Mixers:


10 Ideal Double Balanced Mixer


11 Mixer Performance Specifications

Image rejection

Conversion gain: voltage or power

Port-to-port isolation: dBc

Large signal performance:

gain compression: P1dB

intermodulation distortion spec: third-order intercept (TOI)

Small signal performance: noise figure

Operating range: Spurious-free dynamic range

Conversion Gain Conversion gain or loss is the ratio of the desired IF output (voltage or power) to

the RF input signal value ( voltage or power).

signal RF theof voltager.m.s.

signal IF theof voltager.m.s.Gain Conversion Voltage

source thefrompower Available

load the todeliveredpower IF Gain ConversionPower

If the input impedance and the load impedance of the mixer are both equal to the source impedance, then the voltage conversion gain and the power conversion gain of the mixer will be the same in dB’s.

13 Noise Figure

Noise figure is defined as:

Types of noise:

Resistor thermal Noise

Transistor Noise

Flicker noise

in

added

out

in

GN

N

SNR

SNRF 1

RkTN in 04

SSB Noise Figure

Broadband noise from mixer or front end filter will be located in both image and desired bands

Noise from both image and desired bands will combine in desired channel at IF output Channel filter cannot remove this


For zero IF, there is no image band Noise from positive and negative frequencies combine, but the signals combine as well

DSB noise figure is 3 dB lower than SSB noise figure DSB noise figure often quoted since it sounds better

DSB Noise Figure


Port-to-Port Isolations

RF IF

LO

Isolation

Isolation between RF, LO and IF ports

LO/RF and LO/IF isolations are the most important features.

Reducing LO leakage to other ports can be solved by filtering.

17 1-dB Compression point

System Dynamic range


Intermodulation distortion (IIP3)

IMD consists of the higher order signal products

that are generated when two RF

signals are present at the mixer input.

The IMD will be down and up

converted by the LO as will the

desired RF signal.

21 RFRFIMD nfmff Source :http://rf-circuits.info/radio/rf-mixers/

19 Problem Statement

To design a Wide-band Passive Sub-harmonic Mixer with a goal of

achieving :

― Considerable conversion gain

― Low noise figure

― High linearity

― Low power consumption

― Broad band Matching

20Differential configuration Passive SHM

LOQ (90°)

IFTIA

LN

TA

Bias Tee

Bias Tee

Balun

Quadrature Coupler

LO

RFBuffer

MIXER

LOI (0°)

0°

180°

90°

270 °

Active Balun

21 Cont’d. . .

Advantages of Sub-harmonic mixer

― SHM can reduce the LO frequency to a fraction to RF frequency

―Has low power consumption , better noise figure performance for

high frequency applications.

―Low flicker noise

―Due to absence of DC offsets they have gained interest in direct

conversion receivers

22 De-embedding of noise figure

A. Abidi and J. Leete, “De-embedding the noise figure of differential amplifiers ,” IEEE

Journal of Solid-State Circuits, vol. 34, no. 6, pp. 882-885, Jun. 1999.

Friis’s equation

M. Robens, R. Wunderlich, and S. Heinen, “Differential Noise Figure De-Embedding: A

Comparison of Available Approaches," IEEE Transactions on Microwave Theory and

Techniques, vol. 59, no. 5, pp. 1397-1407, May 2011.

12121

3

1

21

111

n

n

GGG

F

GG

F

G

FFF

23 Cont’d. . .

+

IFVout ,

oR

mixVn,

balvA ,

balvA ,

Balun

+

+

balVn,

balVn,

mixAv,

mixAv,

2

3

+

+

mixVn,

1

3

2Buffer

bufAv,

bufAv,

1

sRRFVin ,

SRVin ,

3

Zin Zout

bufnV ,

Schematic fig. for de-embedding the N.F. of differential configuration SHM

+ -

24Cont’d. . .

+

balvA ,

balvA ,

+

balVn,

balVn,

RFVin ,

SRVin ,

+ -

Zin,bal

sR

+

oR

Schematic fig. for measurement of noise figure for balun

25Cont’d. . .

Noise figure of balun is

The final result is

2,

2,

,

,

2,1

sRnbalvbalins

balin

balnbal

VAZR

Z

VF

2,

2,

2,

1

2

1

2

11

mixvbufv

buf

balv

mixbalcasc

AA

F

A

FFF

26 Desired Specifications values

Parameter Values

Technology 180nm CMOS

Topology LNTA+PSHM+TIA

RF frequency (GHz) 2-6

Conversion gain (dB) >13

DSB NF (dB) < 12.5

S11 (dB) <-10

IIP3 (dBm) [-10,-2]

PDC (mW) Minimum

27 Work Flow ChartLiterature Survey

Problem Statement

Modelling of devices

Circuit Simulation

Optimization of circuit

Compare results

Final design

28 References :

[1] K.-L. Du and M. N. S. Swamy, Technologies, Wireless Communication Systems - From RF Subsystems to 4G Enabling. Cambridge University

Press, 2010.

[2] B. Razavi, RF Microelectronics, 2nd ed. Prentice Hall, 2011.

[3] T. H. Lee, The Design of CMOS Radio-Frequency Integrated Circuits, 2nd ed. Cambridge University Press, 2004.

[4] Gray, P. R. and Meyer, R. G., Design of Analog Integrated Circuits, 3rd Ed., Chap. 10, Wiley, 1993.

[5] Gilbert, B., “Design Considerations for BJT Active Mixers”, Analog Devices, 1995.

[6] Lee, T. H., The Design of CMOS Radio-Frequency Integrated Circuits, Chap. 11, Cambridge U. Press, 1998.

[7] Hayward, W., Introduction to Radio Frequency Design, Chap. 6, American Radio Relay League, 1994.

[8] Maas, S., “Applying Volterra Series Analysis,” Microwaves and RF, p. 55-64, May 1999.

[9] Minicircuits RF/IF Designers Handbook, www.minicircuits.com

[10] Maas, S., “The Diode Ring Mixer”, RF Design, p. 54-62, Nov. 1993.

[11] Maas, S., “A GaAs MESFET Mixer with Very Low Intermodulation,” IEEE Trans. on MTT, MTT-35, pp. 425-429, Apr. 1987.

[12] http://rf-circuits.info/radio/rf-mixers/#Mixer_Specifications

[13] B. R. Jackson, "Subharmonic Mixers in CMOS Microwave Integrated Circuits," PhD Thesis, Queen's University, 2009.

[14] A. Mazzanti, M. Sosio, M. Repossi, and F. Svelto, “A 24 GHz Subharmonic Direct Conversion Receiver in 65 nm CMOS,"

IEEE Transactions on Circuits and Systems I: Regular Papers, vol. 58, no. 1, pp. 88-97, Jan. 2011.

[15] Henry C. Jen, Steven C. Rose, Robert G. Meyer,” A 2.2GHz Sub-Harmonic Mixer for Direct Conversion Receivers in 0.13µm

CMOS”, IEEE International Solid-State Circuits Conference Tech. Dig., pp. 1840–1849, Feb. 2006.

http://rf-circuits.info/radio/rf-mixers/

29

THANK YOU

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5 Cmos Wide-band Low Noise Mixer - Copy