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dc1649afa

DEMO MANUAL DC1649A

 DESCRIPTION

LTC6945 

Ultralow Noise and Spurious

Integer-N Synthesizer

Demonstration circuit 1649A features the LTC

®

6945, an 

ultralow noise and spurious integer-N synthesizer.

DC1649A provides 50Ω SMA connectors for the reference 
frequency (REF+), the reference output buffer (REFO), 
and the two single-ended RF outputs (RF+ and RF–). 

L

, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks and 

PLLWizard and QuikEval are trademarks of Linear Technology Corporation. All other trademarks 
are the property of their respective owners.

Demonstration circuit 590 is used for SPI communication 
with the LTC6945, controlled by the supplied PLLWizard™ 
software. 

Design files for this circuit board are available at 
http://www.linear.com/demo

Figure 1. DC1649A Inputs and Outputs

Downloaded from

Arrow.com.

Summary of Contents for DC1649A

Page 1: ...o single ended RF outputs RF and RF L LT LTC LTM Linear Technology and the Linear logo are registered trademarks and PLLWizard and QuikEval are trademarks of Linear Technology Corporation All other trademarks are the property of their respective owners Demonstration circuit 590 is used for SPI communication with the LTC6945 controlled by the supplied PLLWizard software Design files for this circui...

Page 2: ...hanged if the reference frequency and or power is different than what is recommended in the table above More information can be found in the LTC6945 data sheet The DC590 and PLLWizard application are required to control the DC1649A through a personal computer PC DC590B Configuration The DC590 s QuikEval drivers must be installed before the DC590 will be able to communicate with the LTC6945 Toconfi...

Page 3: ... Microsoft NET You must have Microsoft NET 2 0 or later installed on your computer PLLWizard will not run without it Note that Windows Vista and Windows 7 have at least version 3 5 preinstalled To manually determine your version of NET using Win dows XP click Start Menu Settings Control Panel Add or Remove Programs Depending upon your NET version choose one of two PLLWizard setup programs download...

Page 4: ... and 5V banana jacks and the V VCO turrettoapowersupplyandapplypower see Figure 1 and the Typical DC1649A Requirements and Characteristics table 4 Connect the DC590 to the DC1649A with the provided ribbon cable 5 Run the PLLWizard application 6 InPLLWizard clickFile LoadSettingsandpointtothe DC1649A 10MHz pllset or DC1649A 100MHz pllset filefoundinthePLLWizardinstallationdirectory typically Progra...

Page 5: ... TUNABLE DEVICE SELECTION COMPONENTS RESISTOR FOR ADDITIONAL POLE CAPACITOR FOR ADDITIONAL POLE POWER ENABLE PIN OR REMARKS U3 C26 100pF depopulate R17 C25 and C28 R10 0Ω for passive loop filter R10 100Ω for active loop filter C27 Open for passive loop filter Pick C27 such that 1 2π R10 C27 15 the loop bandwidth in Hz for active loop filter Determined by U3 device power supply specification up to ...

Page 6: ... J8 Con Header 14 Pin 2mm Molex 87831 1420 22 4 J9 J10 J11 J12 Jack Banana Keystone 575 4 23 0 L1 Opt 0402 24 2 L2 L3 Ind Wirebound 68nH 5 0402 Coilcraft 0402HPH 68NXJL 25 1 RZ_P Res Chip 806 1 10W 1 0603 Vishay CRCW0603806RFKEA 26 5 R1 R2 R25 R26 R27 Res Chip 4 99k 1 16W 1 0402 Vishay CRCW04024K99FKED 27 1 R4 Res Chip 330 1 16W 1 0402 Vishay CRCW0402330RFKED 28 1 R5 Res Chip 51 1 1 16W 1 0402 Vis...

Page 7: ...ONSIBILITY TO VERIFY PROPER AND RELIABLE OPERATION IN THE ACTUAL APPLICATION COMPONENT SUBSTITUTION AND PRINTED CIRCUIT BOARD LAYOUT MAY SIGNIFICANTLY AFFECT CIRCUIT PERFORMANCE OR RELIABILITY CONTACT LINEAR TECHNOLOGY APPLICATIONS ENGINEERING FOR ASSISTANCE THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND SCHEMATIC SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS SCALE NONE www linear com 4 11 0...

Page 8: ...NGINEERING FOR ASSISTANCE THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND SCHEMATIC SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS SCALE NONE www linear com 4 11 01 2011 02 27 PM 2 2 ULTRALOW NOISE AND SPURIOUS INTEGER N SYNTHESIZER KIM T MICHEL A N A LTC6945IUFD DEMO CIRCUIT 1649A SIZE DATE V E R O N C I SHEET OF TITLE APPROVALS PCB DES APP ENG TECHNOLOGY Fax 408 434 0507 Milpitas CA 95035 Ph...

Page 9: ... interconnection of its circuits as described herein will not infringe on existing patent rights LAYOUT TOP LAYER The top metal layer of DC1649A is shown here as an example of good PCB layout for the LTC6945 Downloaded from Arrow com Downloaded from Arrow com Downloaded from Arrow com Downloaded from Arrow com Downloaded from Arrow com Downloaded from Arrow com Downloaded from Arrow com Downloaded...

Page 10: ...Y SHALL BE LIABLE TO THE OTHER FOR ANY INDIRECT SPECIAL INCIDENTAL OR CONSEQUENTIAL DAMAGES The user assumes all responsibility and liability for proper and safe handling of the goods Further the user releases LTC from all claims arising from the handling or use of the goods Due to the open construction of the product it is the user s responsibility to take any and all appropriate precautions with...

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