Transcript Tokyo Tech Template

A 60GHz up-conversion mixer
using asymmetric layout with
-41.1dBc LO leakage
Yuki Tsukui, Kenichi Okada
and Akira Matsuzawa
Tokyo Institute of Technology, Japan
Matsuzawa
Matsuzawa
Lab.
& of
Okada
Lab.
Tokyo Institute
Technology
Outline
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1
Background
Mixer topology
Asymmetric layout
Measurement results
Conclusion
Matsuzawa
Matsuzawa
Lab.
& Okada
Lab.
Tokyo Institute
of Technology
Background
2
Characterization of 60GHz
 Attenuation is large.
 Wide bandwidth can be
used without license.
Suitable for short range and very
high-speed wireless communication
High-speed
file/data transfer
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•
•
•
IEEE 802.15.3c
Bandwidth 2.16GHz × 4ch
QPSK ⇒ 3.5Gbps × 4ch
16QAM ⇒ 7.0Gbps × 4ch
Matsuzawa
Matsuzawa
Lab.
& Okada
Lab.
Tokyo Institute
of Technology
Object
3
RF-LO isolation
• Mixer
LO leakage
– LO leakage ⇒ The degradation of EVM
– RF-LO isolation ⇒ Pulling
Smaller LO leakage and RF-LO isolation
Matsuzawa
Matsuzawa
Lab.
& Okada
Lab.
Tokyo Institute
of Technology
60GHz Mixer
4
• Generally, switching mixers for RF
circuits are used.
• Parasitic capacitances causes large LO
leakage and RF-LO isolation.
Matsuzawa
Matsuzawa
Lab.
& Okada
Lab.
Tokyo Institute
of Technology
Double-balanced mixer
5
• This topology can cancel LO signal to RF port
and RF signal to LO port.
• By DC and capacitance mismatch, LO leakage
and RF-LO isolation is larger.
Matsuzawa
Matsuzawa
Lab.
& Okada
Lab.
Tokyo Institute
of Technology
DC mismatch
LO leak [dBc]
0
-10
6
𝟐𝑫𝑪𝒎𝒊𝒔𝒎𝒂𝒕𝒄𝒉
𝑳𝑶𝒍𝒆𝒂𝒌 = 𝟐𝟎 𝐥𝐨𝐠
[dBc]
𝑨𝑩𝑩
-20
-30
-40
-50
0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0
DC mismatch [mV]
• Vth variation causes DC mismatch.
• Larger DC mismatch, Larger LO leakage.
DC mismatch calibration
Matsuzawa
Matsuzawa
Lab.
& Okada
Lab.
Tokyo Institute
of Technology
Cgd mismatch
7
RF-LO isolation [dB]
-30
-40
-50
-60
-70
-80
-90
0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0
Capacitance mismatch [fF]
• Layout causes capacitance mismatch.
• Larger Cgd mismatch, Larger LO leakage and
RF-LO isolation.
 Asymmetric layout
Matsuzawa
Matsuzawa
Lab.
& Okada
Lab.
Tokyo Institute
of Technology
Asymmetric layout
8
• Mixer core excluding intersection
– LO line and RF line cross in matching network
• Mixer core including intersection
– bad symmetrical property
RF+
LO+
RF+
LO+
LO-
RFSymmetrical core
(Not Good)
LORFAsymmetrical core
(Good)
Matsuzawa
Matsuzawa
Lab.
& Okada
Lab.
Tokyo Institute
of Technology
Asymmetric layout
9
• Symmetrical core needs crossed and
complicated matching network.
• Asymmetrical core can realize simple matching
network.
RF+
BB+
BB-
RF-
BB+ BBRF+
LO+
RF-
LO-
Asymmetrical core
LOLO+
Symmetrical core
Matsuzawa
Matsuzawa
Lab.
& Okada
Lab.
Tokyo Institute
of Technology
Schematic
10
• Active mixer
–Large CG
Matsuzawa
Matsuzawa
Lab.
& Okada
Lab.
Tokyo Institute
of Technology
Die photo
11
• Area of mixer core : 160×50[μm2]
Matsuzawa
Matsuzawa
Lab.
& Okada
Lab.
Tokyo Institute
of Technology
RF-LO isolation
• RF-LO isolation is measured using
network analyzer.
• RF-LO isolation @ 60GHz : -37.3dBc
12
Matsuzawa
Matsuzawa
Lab.
& Okada
Lab.
Tokyo Institute
of Technology
Measurement system
13
• BB and LO input : Signal generator
• RF output : Spectrum analyzer
Matsuzawa
Matsuzawa
Lab.
& Okada
Lab.
Tokyo Institute
of Technology
Conversion gain
• BB frequency : 100MHz
• LO frequency : 62.64GHz
14
Matsuzawa
Matsuzawa
Lab.
& Okada
Lab.
Tokyo Institute
of Technology
LO leakage
• DC mismatch calibration
• VgBB on one side is fixed to 0.5V.
• LO leakage : -41.1dBc
15
Matsuzawa
Matsuzawa
Lab.
& Okada
Lab.
Tokyo Institute
of Technology
Performance comparison
Up-conversion
mixer
Technology
Conversion gain
[dB]
RF-LO
Isolation
[dB]
LO leakage [dBc]
Power
consumption
[mW]
This work
16
[1]
[2]
65nm
130nm
90nm
4.3
4.0
4.5
-37.3
-37
-57.5
-41.1
-30
N/A
5.4
24.0
15.1
[1] F. Zhang, et al., Electronics Letters, 2012
[2] T. Tsai, et al., Electronics Letters, 2012
Matsuzawa
Matsuzawa
Lab.
& Okada
Lab.
Tokyo Institute
of Technology
Conclusions
17
• Up-conversion mixer using asymmetric
layout is presented.
• The mixer in 65nm CMOS achieved
conversion gain of 4.3dB, RF-LO
isolation of -37.3dB, LO leakage of
-41.1dBc and power consumption of
5.4mW.
Matsuzawa
Matsuzawa
Lab.
& Okada
Lab.
Tokyo Institute
of Technology
18
Matsuzawa
Matsuzawa
Lab.
& Okada
Lab.
Tokyo Institute
of Technology
Impedance
RF port
19
LO port
• Solid line: measurement, Dotted line: simulation
• Markers show 60GHz point.
• The difference between simulation and measurement
is due to parasitic inductance.
Matsuzawa
Matsuzawa
Lab.
& Okada
Lab.
Tokyo Institute
of Technology
Large-signal characteristics
20
• P1dB : -8.7dBm
• Psat : -5.2dBm
Matsuzawa
Matsuzawa
Lab.
& Okada
Lab.
Tokyo Institute
of Technology