5
dc1705cfa
DEMO MANUAL DC1705C
quick start proceDure
DC1705C Configuration
1. Connect an appropriate reference frequency source (at
J1) and signal analyzers (at J4 and/or J5) using the
SMA connectors (see Figure 1 and the Typical DC1705C
Requirements and Characteristics table).
2. Choose the
MUTE
jumper setting:
JP1 - GND/3.3V
MUTE
position. Select GND to mute the RF output, 3.3V to
un-mute.
3. Connect the GND, 3.3V and 5V banana jacks to a power
supply and apply power (see Figure 1 and the Typical
DC1705C Requirements and Characteristics table).
4. Connect the DC590 to the DC1705C with the provided
ribbon cable.
5. Run the PLLWizard application.
6. In PLLWizard, click File
→
Load Settings and point
to the appropriate pllset file. For example, if you are
using a 10MHz reference with a DC1705C-B to evalu-
ate the LTC6946-2, load the “DC1705-B (LTC6946-2)
10MHz.pllset” file found in the PLLWizard installation
directory (typically Program Files
→
LTC
→
PLLWizard
→
Set Files).
The red LED on DC1705C should turn on indicating that
the loop is locked at 900MHz.
You can then change the values of N_DIV and/or O_DIV
in PLLWizard to change the output frequency.
Troubleshooting
If the red LED does not illuminate, follow the instructions
below:
1. Verify that you are able to communicate with the
DC1705C. The bottom status line in PLLWizard should
read “LTC6946” and “Comm Enabled.” Refer to PLL-
Wizard’s Troubleshoot and Help if not.
2. Verify that the 3.3V and 5V have the correct voltages
on them and that the reference frequency is applied to
the REF
+
IN SMA input.
If the red LED is on but you cannot detect an RF output,
make sure jumper JP1 is at the 3.3V position. Run Help
→
Troubleshoot in PLLWizard if the problem is not resolved.
DC1705C Reconfiguration
You can redesign the frequency plan of the DC1705C us-
ing PLLWizard. You can change the loop filter as found
using PLLWizard by reinstalling the loop filter components
shown in Figure 4.
