ADRF6604

Data Sheet

Rev. B | Page 28 of 32

EVALUATION BOARD CONFIGURATION OPTIONS

Table 10.

Component

Description

Default Condition/

Option Settings

S1, R55, R56, R33

LO select. Switch and resistors to ground the LODRV_EN pin. The LODRV_EN pin setting, in

combination with internal register settings, determines whether the LOP and LON pins

function as inputs or outputs (see the LO Selection Logic section for more information).

S1 = R55 = open

(not installed),

R56 = R33 = 0 Ω,

LODRV_EN = 0 V

LO IN/OUT

SMA Connector

LO input/output. An external 1× LO or 2× LO can be applied to this single-ended input

connector.

LO input

REFIN

SMA Connector

Reference input. The input reference frequency for the PLL is applied to this connector.

Input impedance is 50 Ω.

REFOUT

SMA Connector

Multiplexer output. The REFOUT connector connects directly to the MUXOUT pin. The

on-board multiplexer can be programmed to bring out the following signals: REFIN, 2×

REFIN, REFIN/2, and REFIN/4; temperature sensor output voltage; and lock detect indicator.

Lock detect

CP Test Point

Charge pump test point. The unfiltered charge pump signal can be probed at this test

point. Note that the CP pin should not be probed during critical measurements, such as

phase noise.

R37, C14, R9, R10,

C15, C13, R65, C40

Loop filter. Loop filter components.

R11, R12

Loop filter return. When the internal VCO is used, the loop filter components should be

returned to the DECLVCO pin (Pin 40) by installing a 0 Ω resistor in R12. When an external

VCO is used, the loop filter components can be returned to ground by installing a 0 Ω

resistor in R11.

R12 = 0 Ω (0402),

R11 = open (0402)

R62, R63, VTUNE

SMA Connector

Internal vs. external VCO. When the internal VCO is enabled, the loop filter components are

connected directly to the VTUNE pin (Pin 39) by installing a 0 Ω resistor in R62. To use an

external VCO, R62 should be left open. A 0 Ω resistor should be installed in R63, and the

voltage input of the VCO should be connected to the VTUNE SMA connector. The output of

the VCO is brought back into the PLL via the LO IN/OUT SMA connector.

R62 = 0 Ω (0402),

R63 = open (0402)

R2

R2 = open (0402)

RFIN SMA Connector

RF input. The RF input signal should be applied to the RFIN SMA connector. The RF input of

the ADRF6604 is ac-coupled; therefore, no bias is necessary.

R3 = R23 = open (0402)

T3

IF output. The differential IF output signals from the ADRF6604 (IFP and IFN) are converted

to a single-ended signal by T3.