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dc1846af

DEMO MANUAL DC1846A

DESCRIPTION

LTC6947

Ultralow Noise and Spurious

Fractional-N Synthesizer

Demonstration circuit 1846A features the LTC®6947, an

Ultralow Noise and Spurious Fractional-N Synthesizer.

DC1846A provides 50Ω SMA connectors for the reference

frequency (REF+) and the two single-ended RF outputs

(RF+ and RF–).

L

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

FracNWizard is a trademark of Linear Technology Corporation. All other trademarks are the

property of their respective owners.

A DC590 USB serial controller board is used for SPI com-

munication with the LTC6947, controlled by the supplied

FracNWizard™ software.

Design files for this circuit board are available at

http://www.linear.com/demo

Figure 1. DC1846A Connections

 

 

 

 

 

Frequency 

reference input, 

SMA 

External VCO 

input, SMA 

Differential 

output of VCO 

buffer, SMA 

3.3 V DC supply, 

banana jacks 

5 V DC supply, 

banana jacks

Ribbon 

cable 

connection 

to DC590 

Active loop filter op‐

amp DC supply, turret 

U3 (VCO) DC 

supply, turret 

U4 (VCO or VCXO) 

DC supply, turret 

Enable (pin 2) 

of U4 (VCO or 

VCXO), turret