Evaluate: MAX9989/MAX9990
MAX9989/MAX9990 Evaluation Kits
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Quick Start
The MAX9987/MAX9988 EV kits are fully assembled and
factory tested. Follow the instructions in the Connections
and Setup section for proper device evaluation.
Test Equipment Required
Table 1 lists the equipment required to verify the opera-
tion of the MAX9989/MAX9990 EV kits. It is intended as
a guide only, and some substitutions are possible.
Connections and Setup
This section provides a step-by-step guide to testing
the basic functionality of the EV kits. As a general pre-
caution to prevent damaging the outputs by driving
high-VSWR loads, do not turn on DC power or the RF
signal generator until all connections are made:
1) Calibrate the power meter at 900MHz for the
MAX9989, or at 1800MHz for the MAX9990. Be sure
to use a power sensor rated to at least 20dBm.
Measure the loss of the 20dB attenuator (pad) that is
connected to OUTLO; account for this loss as an off-
set in the power meter.
2) Connect a 20dB pad to the LO driver output
(OUTLO). The 20dB pad maintains a reasonable
load VSWR for the output drivers and protects the
RF equipment from accidental overload.
3) Connect a 50Ω termination to OUTPLL.
4) For the MAX9989, set the RF signal generator for
900MHz CW (i.e., unmodulated) at +10dBm
(accounts for 3dB loss of input pad); for the
MAX9990, set the generator for 1800MHz at
+12dBm. Connect the generator to the EV kit input
through a 3dB pad. Disable the RF output until all
connections are made.
5) Connect the power sensor to OUTLO’s 20dB pad.
6) Set the DC supply to +5.0V (set the current limit to
around 250mA, if possible). Disable the output volt-
age and connect the supply to the EV kit through the
ammeter.
7) Enable the supply.
8) Enable the RF signal generator’s output.
Testing the Buffer
1) From the procedure above, the power meter should
be reading a power of about +17dBm. Keep in mind
that because of a 2nd harmonic component in the
output, these measured results are slightly higher
than the true on-frequency RF power.
2) Ensure that the supply current is not more than
122mA at V
CC
= 5.25V and P
IN
= +10dBm.
3) Leaving the 20dB power pad connected to OUTLO,
move the power detector to OUTPLL (removing the
50Ω termination) and verify an output level of about
+3dBm. Be sure to turn off the 20dB offset.
4) After testing, disable the RF generator, disconnect
the supply, then disconnect the RF cables.
Layout Considerations
A properly designed PC board is an essential part of
any RF/microwave circuit. Keep RF signal lines as short
as possible to reduce losses, radiation, and induc-
tance. For best performance, route the ground pin
traces directly to the exposed paddle underneath the
package. This paddle should be connected to the
ground plane of the board by using multiple vias under
the device to provide the best RF/thermal conduction
path. Solder the exposed paddle, on the bottom of the
device package, to a PC board exposed pad.
