Download A Wide Locking Range Differential Colpitts Injection Locked

A Wide Locking Range Differential Colpitts
Injection Locked Frequency Divider
Chien-Feng Lee, Sheng-Lyang Jang, Senior Member, IEEE,
and M.-H. Juang, Senior Member, IEEE
Presenter: 楊 子 岳
2017/5/23
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Abstract
• A new wideband Colpitts injection locked
frequency divider (ILFD)
• Divide-by-two ILFD can provide wide locking
range, supply voltage of 2.4 V, the tuning
range of the free running ILFD is from 4.46 to
5.6 GHz,about 1.14 GHz, and the locking
range of the ILFD is from 8.03 to 11.63 GHz,
about 3.6 GHz
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Outline
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Introduction
Single-ended Colpttis oscillator topology
Differential Colpttis ILFD topology
Measurement and discussion
Conclusion
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Introduction
• For high speed operation, the FD utilizing an
LC resonator is the most suitable one among
various types of FDs , because the operating
frequency is determined by the resonant
frequency
• Tuning varactors and degrading the resonator
Q-factor are often used to extend the locking
range.
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Single-ended Colpttis oscillator topology
•Schematic of a
pMOS core Colpitts
oscillator & Smallsignal equivalent
circuit with parasitic.
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Differential Colpttis ILFD topology
•Proposed differential
Colpitts ILFD
topology
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Differential Colpttis ILFD topology
•Relationship
between ac input
voltage and ac output
voltages of the
differential ILFD
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Measurement and discussion
•Chip photograph
of the proposed
differential
Colpitts ILFD
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Measurement and discussion
Vinj =1.4 V, as the tuning
voltage sweeps from 0 to 2.4 V,
the oscillation frequency varies
from 4.46 to 5.6 GHz, indicating a
tuning range of 1.14 GHz
•Measured frequency tuning
characteristics of the free running
oscillator,Vinj = 1.2, 1.4, 1.6 V
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Measurement and discussion
•Measured
relationship between
input sensitivity
and operating
frequency
•supply voltage
= 2.4 V.
•Vtune
= 0, 1.2,1.5,2.4 V
•Vinj = 1.4 V
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Measurement and discussion
The phase noise of the
free-running ILFD at 1-MHz
offset is about -110.8 dBc/Hz at
the output frequency of 4.93
GHz
After the injection signal
is applied to the ILFD, the
phase noise of the ILFD
becomes
-135.4 dBc/Hz
•Measured phase noises of the free-running,
injection-reference and injection-locked of the
ILFD at low band Vdd = 2.4v,Vtune = 1.2v,fo =
4.93GHz,Injection power = -4dBm
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Conclusion
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