Evaluate: MAX9987/MAX9988
MAX9987/MAX9988 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 MAX9987/MAX9988 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 RF
signal generators until all connections are made.
1) Calibrate the power meter at 900MHz for the
MAX9987, or at 1800MHz for the MAX9988. Import-
ant: Use a power sensor rated to at least 0dBm.
Measure the loss in the 20dB attenuator (pad) that
will be connected to OUT1; account for this loss as
an offset in the power meter.
2) Connect the 20dB pad to OUT1. The 20dB pad
maintains a reasonable load VSWR for the output
driver and protects the RF equipment from acci-
dental overload.
3) Connect a 50Ω termination to OUT2.
4) For the MAX9987, set the RF signal generator for
900MHz CW (i.e., unmodulated) at +10dBm
(accounts for 3dB loss of input pad); for the MAX9988,
set the generator for 1800MHz at +12dBm. Connect
generator to EV kit input through a 3dB pad. Disable
the RF output until all connections are made.
5) Connect the power sensor to OUT1’s 20dB pad.
6) Set DC supply to +5.0V (set current limit around
250mA, if possible), and connect supplies to the EV
kit through the ammeter.
7) Enable the RF signal generator’s output.
Testing the Buffers/Splitters
1) From the procedure above, the power meter should
be reading a power of about +17dBm.
2) Ensure that the supply current is not more than
175mA at VCC = 5.25V and PIN = +10dBm.
3) Disable the RF generator, turn off the DC supply
and swap the power detector/power pad to OUT2
(moving the 50Ω termination to OUT1), and re-
check output power level and stability over supply,
input power, and frequency, if desired.
4) Leaving the 20dB pad and 50Ω termination con-
nected to OUT2 and OUT1, move the power detec-
tor to OUTPLL and verify an output level of around
+3dBm.
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.
