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dc1959af

DEMO MANUAL DC1959A

assembly options

typical Dc1959a reQuirements anD characteristics

Troubleshooting

If the red LED does not illuminate, follow the instructions

below:

1. Verify that you are able to communicate with the

DC1959A.ThebottomstatuslineinFracNWizardshould

read LTC6948 and Comm Enabled as shown in Figure 3.

Refer to FracNWizard’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 ->

TroubleshootinFracNWizardiftheproblemisnotresolved.

DC1959A Reconfiguration

YoucanredesignthefrequencyplanoftheDC1959Ausing

FracNWizard. You can change the loop filter as found us-

ing FracNWizard by reinstalling the loop filter components

shown in Figure 1.

Quick start proceDure

Table 1. DC1959A Options and Frequency Ranges

ASSEMBLY VERSION

PART NUMBER

VCO FREQUENCY RANGE (GHz)

OUTPUT DIVIDER SETTINGS

DC1959A-A

LTC6948IUFD-1

2.240 to 3.740

Integers 1 through 6

DC1959A-B

LTC6948IUFD-2

3.080 to 4.910

Integers 1 through 6

DC1959A-C

LTC6948IUFD-3

3.840 to 5.790

Integers 1 through 6

DC1959A-D

LTC6948IUFD-4

4.200 to 6.390

Integers 1 through 6

PARAMETER

INPUT OR OUTPUT PHYSICAL LOCATION

DETAILS

3.3V Power Supply

Input

J6 and J7 Banana Jacks

Low-Noise and Spur-Free 3.3V, 130mA

5V Power Supply

Input

J8 and J9 Banana Jacks

Low-Noise and Spur-Free 5V, 33mA

REF+ IN, Reference Frequency Input

J1 SMA Connector

Low-Noise 100MHz*, 6dBm to 10dBm into 50Ω, See Note

Below

RF+ and RF–

Two Outputs

J4 and J5 SMA Connectors**

Frequency: 907MHz*, Power: 0dBm, Frequency Range:

Depends on the Version of the LTC6948 Device – Refer to

Table 1

Loop Bandwidth

–

Set by Loop Filter Component Values Approximately 160kHz* Depending on the DC1959A Version

*These frequencies are for the DC1959A fracnset files included with FracNWizard.

**Any unused RF output must be terminated with 50Ω, or poor spurious performance may result.

Note: A low noise 100MHz reference frequency, such as the Wenzel 501-04516D OCXO, is recommended. If using a different frequency, make sure to

update the Fref and R_DIV boxes under the System tab in FracNWizard so that Fpfd is still 50MHz. For example, if a 250MHz clock is used, Fref should be

changed to 250MHz and R_DIV to 5. Ref BST and FILT under the System tab in FracNWizard might need to be changed if the reference frequency and/or

power is different than what is recommended in the table above. More information can be found in the LTC6948 data sheet.