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Ultralow Noise & Spurious 350MHz to 6GHz Integer-N PLL/Synthesizer
Suppresses System Noise

MILPITAS, CA – December 19, 2011 –  Linear Technology announces the LTC6945, a high performance 6GHz integer-N frequency synthesizer with outstanding -226dBc/Hz normalized closed-loop in-band phase noise, excellent -274dBc/Hz normalized in-band 1/f noise, a wideband phase noise floor of -157dBc/Hz and
best-in-class -102dBc spurious output. In a typical 900MHz application, these performance attributes enable a closed-loop phase noise of -100dBc/Hz at 1kHz offset. The LTC6945 is designed to work in conjunction with an external low noise VCO up to 6GHz. In addition, the device has an on-chip output divider that is programmable from 1 through 6 to extend the tuning frequency coverage to as low as 350MHz.

The LTC6945 comprises a low noise reference buffer, a reference divider,phase-frequency detector (PFD) with phase-locked indicator, an ultralow noise programmable charge pump and an integer feedback divider to attain very low noise PLL operation. The on-chip SPI-compatible bidirectional serial port allows frequency tuning and control, and read back of the register and loop status information.

The low phase noise and spurious capabilities of the LTC6945 enhance the performance of RF and wireless equipment of all types, including multiband basestations supporting LTE, W-CDMA, UMTS, CDMA, multicarrier GSM and WiMAX standards. Its wide frequency range 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 to interface with the LTC6945’s evaluation board. Designers can perform simulations and optimization with the PLLWizard software, and then interactively verify their designs on the actual demonstration circuit. The PLLWizard design tool is available for download free of charge at

The LTC6945 is specified over the full case temperature range from -40°C to 105°C. The LTC6945 is now available from stock in a 4mm x 5mm, 28-lead plastic QFN package, priced starting at $4.95 each in 1,000-piece quantities. For more information, visit

Summary of Features: LTC6945

  • 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: -102dBc
  • Programmable Charge Pump Up to 11.2mA Output Current
  • PLLWizard™ Design Tool Software Support
  • On-Chip Output Divider Providing Wide Tuning Frequency Range to as Low as 350MHz

Ultralow Phase Noise & Spurious 6GHz
Frequency Synthesizer


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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, ÁModule and are registered trademarks and PLL Wizard is a trademark of Linear Technology Corp. All other trademarks are the property of their respective owners.

Worldwide Contacts

North America and General Information
John Hamburger
Tel: (408) 432-1900 ext. 2419

Doug Dickinson
Tel: (408) 432 1900 ext. 2233
  China (PRC)
Fanny Lau
Tel: 852-2428-0303

Angela Ao
Tel: (8610)6522 8081
Yoshikazu Funasaki
Tel: 81-3-5226-7291

Hitoshi Kasai
Tel: +0422-47-5319

Desiree Park
Tel: +82-2-565-6625
Alice Wang
Tel: +886-2-28974705

Ralf Stegmann
Tel: +49 (0) 71319234-11

UK & Nordic
Alan Timmins
Tel: +44-1252-629937

Simona Labianca
Tel: +39 340 0571697
Clotilde Zeller
Tel: +33 1 4614 87 09

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