5 cmos wide-band low noise mixer - copy
DESCRIPTION
Presentation on CMOS RF MIXERS for wireless communicationTRANSCRIPT
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)
Source :http://rf-circuits.info/radio/rf-mixers/
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.
Source :http://rf-circuits.info/radio/rf-mixers/
6 Switching or sampling mixers
Let
Multiply by the LO switching function T(t)
)cos()( tVtV RFRIN
Source :http://rf-circuits.info/radio/rf-mixers/
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:
Source :http://rf-circuits.info/radio/rf-mixers/
10 Ideal Double Balanced Mixer
Source :http://rf-circuits.info/radio/rf-mixers/
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
Source :http://rf-circuits.info/radio/rf-mixers/
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
Source :http://rf-circuits.info/radio/rf-mixers/
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
Source :http://rf-circuits.info/radio/rf-mixers/
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.
29
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