User Guide

EVAL-ADRF5715

EVALUATION BOARD HARDWARE

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Rev. 0 | 3 of 7

OVERVIEW

The ADRF5715-EVALZ is a connectorized board, assembled with

the ADRF5715 and its application circuitry. All components are

placed on the primary side of ADRF5715-EVALZ. An assembly

drawing for the ADRF5715-EVALZ is shown in Figure 8, and an

evaluation board schematic is shown in Figure 7.

BOARD LAYOUT

The ADRF5715-EVALZ is designed using RF circuit design techni-

ques on a 4-layer printed circuit board (PCB). The PCB stack-up is

shown in Figure 2.

Figure 2. Evaluation Board Stack-Up

The outer copper layers are 1.5 oz (2.2 mil) thick and the inner

layers are 0.5 oz (0.7 mil) thick.

The top dielectric material is 12 mil Rogers 4003, which provides 50

Ω controlled impedance and optimizes the high frequency perform-

ance. All RF traces are routed on the top layer, and the second

layer is used as the ground plane for RF transmission lines. The

remaining two layers are also ground planes filled with FR4 material

to manage the thermal rise during high power operations and

are supported with dense and filled vias to the PCB bottom for

thermal relief. The overall board thickness is approximately 62 mil

for mechanical strength.

The RF transmission lines are designed using a coplanar wave-

guide (CPWG) model with a width of 16 mil and ground spacing

of 6 mil to have a characteristic impedance of 50 Ω. Ground

via fences are arranged on both sides of the CPWG to improve

isolation between nearby RF lines and other signal lines.

The exposed ground pad of the ADRF5715, which is soldered

on the PCB ground pad, is the main thermal conduit for heat

dissipation. The PCB ground pad is densely populated with filled,

through vias to provide the lowest possible thermal resistance path

from the top to the bottom of the PCB. The connections from the

package ground leads to ground are kept as short as possible.

POWER SUPPLY AND CONTROL INPUTS

The ADRF5715-EVALZ has two power-supply inputs, three control

inputs, and a ground, as shown in Table 1. The DC test points

are populated on VDD, VSS, D0, and GND. A 3.3 V supply is

connected to the DC test points on VDD, and the −3.3 V supply is

connected to the DC test points on VSS. Ground reference can be

connected to GND. Connect the control input, D0, to 3.3 V or 0 V.

The typical total current consumption for the ADRF5715 is between

630 mA and 660 mA.

The VDD and VSS supply pins and control pins of the ADRF5715

are decoupled with 100 pF capacitor.

Table 1. Power Supply and Control Inputs

Test Point

Description

VDD

+3.3 V supply voltage

VSS

−3.3 V supply voltage

D0

Control Input 1

RF INPUTS AND OUTPUTS

The ADRF5715-EVALZ has four edge-mounted, 2.92 mm connec-

tors for the RF inputs and outputs, as shown in Table 2.

Table 2. RF Inputs and Outputs

SMA Connector

Description

ATTIN

Attenuator input

ATTOUT

Attenuator output

THRU1

Thru line input and output

THRU2

Thru line input and output

The ADRF5715-EVALZ is shipped together with a thru line that

calibrates out the board loss effects from the measurements deter-

mining the device performance at the pins of the IC.