Ultralow Noise & Spurs 373MHz to 5.79GHz Integer-N Synthesizers with Integrated VCO Improve System Performance

News Release ⎜ www.linear.com
Ultralow Noise & Spurs 373MHz to 5.79GHz Integer-N
Synthesizers with Integrated VCO Improve System Performance
MILPITAS, CA – September 28, 2011 – Linear Technology announces the LTC6946, the first
device in a family of high performance integer-N frequency synthesizers with integrated VCO,
delivering -226dBc/Hz normalized closed-loop in-band phase noise, superior -274dBc/Hz
normalized in-band 1/f noise, and best-in-class -103dBc spurious output. In a typical 900MHz
application, these performance attributes help to achieve a closed-loop phase noise of
-100dBc/Hz at 1kHz offset. The device is available in three frequency options: the LTC6946-1
tunes from 2.240GHz to 3.740GHz; the LTC6946-2 from 3.080GHz to 4.910GHz; and the
LTC6946-3 covers 3.840GHz to 5.790GHz. In addition, each part has an on-chip output divider
that is programmable from 1 through 6 to extend frequency coverage to as low as 373MHz.
This family of devices integrates a low noise 5.7GHz phase-locked loop (PLL), which
includes a reference divider, phase-frequency detector (PFD) with phase-locked indicator,
ultralow noise charge pump, and integer feedback divider to attain very low noise PLL operation.
The PLL circuit is tightly coupled to a low noise VCO as well as internal self-calibration to
ensure optimum VCO resonator tuning for best phase noise performance. The VCO requires no
external components. The on-chip SPI compatible bidirectional serial port allows frequency
tuning and control, and read back of register and loop status information.
The low phase noise and spurious capabilities of this family of frequency synthesizers
enhance the performance of multiband basestations supporting LTE, W-CDMA, UMTS, CDMA,
GSM and WiMAX standards. Its high frequency capability also supports point-to-point
broadband wireless access, military, avionics, and high performance test and measurement
applications.
The PLLWizard™ comprehensive PC-based design tool software is available to facilitate
interactive control and interface with the LTC6946’s evaluation board. Designers can perform
simulations and optimization with the PLLWizard software, and then interactively verify their
Ultralow Noise & Spurs 373MHz to 5.79GHz Integer-N
Synthesizers with Integrated VCO Improve System Performance
page 2
designs on the actual demonstration circuit. The PLLWizard design tool software is available for
download free of charge from the Linear Technology website at www.linear.com/synthesizers.
All versions of the LTC6946 are specified over the full case temperature range from
-40°C to 105°C. The products are available in a 4mm x 5mm, 28-lead plastic QFN package.
Prices start at $5.75 each in 1,000-piece quantities and are available immediately from stock. For
more information visit, www.linear.com/product/LTC6946
Photo Caption: Ultralow Phase Noise & Spurious 5.7GHz Frequency Synthesizers with
Integrated VCO
Summary of Features: LTC6946
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Outstanding In-Band Phase Noise: -226dBc/Hz (Closed-Loop, Normalized)
Best-In-Class In-Band 1/f Noise: -274dBc/Hz (Closed-Loop, Normalized)
-157dBc/Hz Wideband Output Phase Noise Floor
Very Low Spurious Output: -103dBc
Temperature Stabilized VCO with Self-Calibration
Programmable Charge Pump Up to 11.2mA Output Current
PLLWizard™ Design Tool Software Support
On-Chip Output Divider Providing Wide Tuning Frequency Range up to 5.79GHz
Internal VCO Frequency
Output Freq. (O DIV=1)
Output Freq. (O DIV=2)
Output Freq. (O DIV=3)
Output Freq. (O DIV=4)
Output Freq. (O DIV=5)
Output Freq. (O DIV=6)
Output Frequency Range (GHz)
LTC6946-1
LTC6946-2
LTC6946-3
2.240 to 3.740
3.080 to 4.910
3.840 to 5.790
2.240 to 3.740
3.080 to 4.910
3.840 to 5.790
1.120 to 1.870
1.540 to 2.455
1.920 to 2.895
0.747 to 1.247
1.027 to 1.637
1.280 to 1.930
0.560 to 0.935
0.770 to 1.228
0.960 to 1.448
0.448 to 0.748
0.616 to 0.982
0.768 to 1.158
0.373 to 0.623
0.513 to 0.818
0.640 to 0.965
Ultralow Noise & Spurs 373MHz to 5.79GHz Integer-N
Synthesizers with Integrated VCO Improve System Performance
page 3
About Linear Technology
Linear Technology Corporation, a member of the S&P 500, has been designing, manufacturing
and marketing a broad line of high performance analog integrated circuits for major companies
worldwide for three decades. The Company’s products provide an essential bridge between our
analog world and the digital electronics in communications, networking, industrial, automotive,
computer, medical, instrumentation, consumer, and military and aerospace systems. Linear
Technology produces power management, data conversion, signal conditioning, RF and interface
ICs, and µModule® subsystems.
LT, LTC, LTM, µModule and
are registered trademarks and PLLWizard is a trademark of Linear Technology
Corp. All other trademarks are the property of their respective owners.
Press Contacts:
North America / Worldwide
UK & Nordic
John Hamburger, Director Marketing
Communications
[email protected]
Tel: 408-432-1900 ext 2419
Alan Timmins
[email protected]
Tel: +44-1-252-629937
Doug Dickinson, Media Relations Manager
[email protected]
Tel: 408-432-1900 ext 2233