E
MAX2642/MAX2643 Evaluation Kits
2
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Quick Start
The MAX2642/MAX2643 EV kits are fully assembled and
factory tested. Follow the instructions in the
Connections
and Setup
section for proper device evaluation.
Test Equipment Required
An RF signal generator capable of delivering -10dBm
of output power and a frequency range covering the
MAX2642/MAX2643 (800MHz to 1000MHz, for exam-
ple)
An RF spectrum analyzer that covers the operating
frequency range
A DC power supply capable of supplying +2.7V to
+5.5V
Two 50
coaxial cables with SMA connectors
An ammeter to measure supply current (optional)
A noise figure meter (optional)
A network analyzer for measuring gain and return
loss (optional)
Connections and Setup
Checking Power Gain
1) Connect a DC supply (preset to +3.0V) to the V
CC
and GND terminals (through an ammeter, if desired)
on the EV kit.
2) Set the RF generator for an output frequency of
900MHz at a power level of -30dBm. Connect the RF
generator
’
s output to the RFIN SMA connector.
3) Connect the coaxial cable from the RFOUT SMA con-
nector to the spectrum analyzer.
4) Turn on the DC supply. The supply current should
read approximately 5mA (if using an ammeter).
5) Activate the RF generator
’
s output. A signal on the
spectrum analyzer
’
s display should indicate a typical
gain of +17dB after accounting for cable and board
losses.
6) Optional: For the MAX2642, set the jumper JU2 to the
V
CC
position. The power gain should now be
+3.5dB.
7) Optional: Another method of determining gain is by
using a network analyzer. This has the advantage of
displaying gain vs. a swept frequency band, in addi-
tion to displaying input and output return loss. Refer
to the user manual of the network analyzer for setup
details.
Checking Noise Figure
Noise figure measurements on low-noise devices such
as the MAX2642/MAX2643 are extremely sensitive to
board and lab setup losses and parasitics. There are
many techniques and precautions for measuring low
noise figure. A detailed explanation of these items
would exceed the scope of this document. Take into
account PC board and external components loss when
performing noise-figure measurements. The typical
input losses on these EV kits is 0.25dB. For more infor-
mation on how to perform this level of noise-figure mea-
surement, refer to the noise-figure meter operating
manual and to Hewlett Packard
’
s application note #57-2,
Noise Figure Measurement Accuracy.
Layout Considerations
Good PC board layout is an essential part of an RF cir-
cuit
’
s design. The EV kit PC board can serve as a guide
for laying out a board using the MAX2642/MAX2643.
Generally, the V
CC
node on the PC board should have
a decoupling capacitor located close to the device,
and additional capacitors may be needed for long V
CC
lines. This minimizes supply coupling. Proper grounding
of the GND pins is essential. Connect the GND pins to
the ground plane either directly, through vias, or both.