Circuit Note

CN-0311

Rev. 0 | Page 3 of 4

Figure 3. Sideband Suppression Measurement Test Setup (Simplified Diagram)

COMMON VARIATIONS

The PLL-to-modulator interface described is applicable to all

I/Q modulators that contain a 2XLO-based phase splitter. It is

also applicable to 2XLO-based I/Q demodulators, such as the

ADL5387.

CIRCUIT EVALUATION AND TEST

The CN-0311 uses the EVAL-ADF4351EB1Z and the ADL5385-

EVALZ for the evaluation of the described circuit, allowing for

quick setup and evaluation. The EVAL-ADF4351EB1Z uses

the standard ADF4351 programming software contained on the

CD that accompanies the evaluation board.

Equipment Needed

The following equipment is needed:

•

A PC with a USB port that contains Windows® XP, Vista, or

Windows 7

•

The EVAL-ADF4351EB1Z evaluation board

•

The ADL5385-EVALZ evaluation board,

•

ADF4351 programming software

•

Power supplies (5 V, 500 mA)

•

An I-Q signal source, such as a Rohde & Schwarz AMIQ

•

A spectrum analyzer

Also, see the UG-435 User Guide for the EVAL-ADF4351EB1Z

evaluation board, the ADF4351 data sheet, and the ADL5385

data sheet.

Getting Started

A description of the circuit, the schematic, and a block diagram

of the test setup is detailed within the CN-0311 (see Figure 1 and

Figure 3). The UG-435 user guide details the installation and use of

the EVAL-ADF4351EB1Z evaluation software. The UG-435 also

contains the board setup instructions, and the board schematic,

layout, and bill of materials. The ADL5385-EVALZ board

schematic, block diagram, bill of materials, layout, and assembly

information is included in the ADL5385 data sheet. See the

ADF4351 data sheet and ADL5385 data sheet for device

information.

Functional Block Diagram

The functional block diagram of the described test setup is

shown in Figure 3.

Setup and Test

After setting up the equipment, use standard RF test methods to

measure the sideband suppression of the circuit.

R&S AMIQ

POWER SUPPLY

ADL5385 EVALUATION BOARD

ADAPTED TO ACCEPT

DIFFERENTIAL LO INPUTS

ADF4351

EVALUATION BOARD

SPECTRUM

ANALYZER

IP

LOIP

LOIN

RFOUT

IN

QP

QN

5V