Linear Technology DC1846A, Демонстрационное руководство

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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