Evaluation Board Hardware; Overview; Board Layout; Power Supply And Control Inputs - Analog Devices EVAL-ADRF5700 User Manual

User Guide

EVALUATION BOARD HARDWARE

OVERVIEW

The ADRF5700-EVALZ is a connectorized board, assembled with
the ADRF5700 and its application circuitry. All components are
placed on the primary side of ADRF5700-EVALZ. An assembly
drawing for the ADRF5700-EVALZ is shown in
evaluation board schematic is shown in

BOARD LAYOUT

The ADRF5700-EVALZ was designed using RF circuit design tech-
niques 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 mil thick and the inner layers are
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 a CPWG to improve isolation
between nearby RF lines and other signal lines.
The exposed ground pad of the ADRF5700, 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.
analog.com
Figure 6 and an
Figure 5.
EVAL-ADRF5700

POWER SUPPLY AND CONTROL INPUTS

The ADRF5700-EVALZ has two power supply inputs, six control
inputs, and a ground, as shown in
are populated on VDD, VSS, LE, D2, D3, D4, D5, D6, and GND.
A 3.3 V supply is connected to the DC test point on VDD and a
−3.3 V supply is connected to the DC test point on VSS. Ground
reference can be connected to GND. Connect the control inputs,
LE, D2, D3, D4, D5, and D6 to 3.3 V or 0 V. The typical total current
consumption for the ADRF5700 is 0.87 mA for control inputs = 0 V,
and 0.67 mA for control inputs = 3.3 V.
The VDD and VSS supply pins of the ADRF5700 are decoupled
with 100 pF capacitors.
Table 1. Power Supply and Control Inputs
Test Points Description
VDD +3.3 V supply voltage
VSS −3.3 V supply voltage
LE Latch enable input
D2 Parallel control input for 2 dB attenuator bit
D3 Parallel control input for 4 dB attenuator bit
D4 Parallel control input for 8 dB attenuator bit
D5 Parallel control input for the first 16 dB attenuator bit
D6 Parallel control input for the second 16 dB attenuator bit
GND Ground

RF INPUTS AND OUTPUTS

The ADRF5700-EVALZ has four edge mounted, 2.92 mm connec-
tors for the RF inputs and outputs, as shown in
Table 2. RF Inputs and Outputs
2.92 mm Connectors Description
ATTIN Attenuator input
ATTOUT Attenuator output
THRU1 Through line input and output
THRU2 Through line input and output
The through calibration line, connecting the THRU1 and THRU2
RF connectors, calibrates out the board loss effects from the
measurements of the ADRF5700-EVALZ to determine the device
performance at the pins of the IC.
loss for the ADRF5700-EVALZ at room temperature, as well as the
embedded and deembedded insertion loss for the ADRF5700.
Table 1. The DC test points
Table 2.
Figure 3 shows the typical board
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