CN-0245

Circuit Note

Rev. 0 | Page 4 of 5

Table 1. ADF4350 RF Output Filter Component Value (DNI = Do Not Insert)

Frequency Range

(MHz)

L1

(nH)

L2

(nH)

C1a

(pF)

C1c

(pF)

C2a

(pF)

C2c

(pF)

C3a

(pF)

C3c

(pF)

a. 500–1300

27 nH|| 50 Ω

3.9

3.9

DNI

4.7

DNI

5.6

DNI

3.3

b. 850–2450

19 nH || (100 Ω in position C1c)

2.7

2.7

3.3

100 Ω

4.7

DNI

3.3

DNI

c. 1250–2800

50 Ω

0 Ω

3.6

DNI

DNI

2.2

DNI

1.5

DNI

d. 2800–4400

3.9 nH

0 Ω

0 Ω

DNI

DNI

DNI

DNI

DNI

DNI

120pF

120pF

0.1µF

LOIP

LOIN

ADL5380

ADF4350

3.3V

C1a

C2a

C3a

C1a

C2a

C3a

C1c

C2c

C3c

1nF

1nF

L1

L2

L1

L2

12

13

3

4

Figure 8. ADF4350 RF Output Filter Schematic

COMMON VARIATIONS

The interface discussed above is applicable to any PLL with

differential LO outputs and to any 1 × LO or 2 × LO-based I/Q

demodulator. The ADL5382 is a 1 × LO-based I/Q demodulator

that operates from 700 MHz to 2700 MHz and provides slightly

higher IP3 than the ADL5380. TheAD8347 (1 × LO) and

AD8348 (2 × LO) are lower power I/Q demodulators that

integrate front-end variable gain amplifiers and fixed-gain

baseband amplifiers.

CIRCUIT EVALUATION AND TEST

The circuits shown in Figure 4 and Figure 6 were implemented

using the CN-0134 evaluation board (CFTL-0134EVALZ) and

the ADL5387 or ADL5380 evaluation boards. The CN-0134

evaluation platform includes the ADF4350, pads for an LO

filter, and differential LO outputs to SMA connectors.

The ADF4350 must be programmed, and the software is

contained on the CD that accompanies the evaluation board.

Table 2 provides the ordering guide for the various evaluation

boards.

The CN-0134 evaluation board is configured by default to an

850 MHz to 2450 MHz filter design as specified in Table 1. To

implement an alternative filter, the appropriate components

must be swapped out.

Table 2. Evaluation Board Information

Evaluation Board

ADL5387

ADL5387-EVALZ

ADL5380

Low Band (400 MHz to 3 GHz)

Mid Band (3 GHz to 4 GHz)

ADL5380-30A-EVALZ

ADL5380-29A-EVALZ

CN-0134

CFTL-0134-EVALZ

Equipment Needed

•

Windows XP, Windows Vista (32-bit), or Windows 7

(32-bit) PC with USB port

•

Evaluation boards as listed in Table 2

•

RF source (Rohde & Schwarz SMT06 or equivalent)

•

Spectrum analyzer (Rohde & Schwarz FSEA30 or

equivalent)

•

Power supplies:

•

ADL5387-EVALZ: +5 V

•

ADL5380-30A-EVALZ: +5 V

•

CFTL-0134-EVALZ: +5.5 V

Test

The CN-0134 evaluation platform allows easy evaluation and

has an integrated crystal oscillator on board. A PC with the

ADF4350 software is required to program the synthesizer to the

desired LO frequency. The ADL5387/ADL5380 quadrature

demodulator will downconvert the RF frequency to baseband.

The differential I and Q baseband outputs are applied to the

FSEA spectrum analyzer in the FFT mode, and image rejection

is measured.

Additional documentation can be found in the following design

support packages for CN-0245, CN-0134, and CN-0144:

CN-0245 Design Support Package:

www.analog.com/CN0245-DesignSupport

CN-0134 Design Support Package:

www.analog.com/CN0134-DesignSupport

CN-0144 Deign Support Package:

www.analog.com/CN0144-DesignSupport