Datasheet

Evaluates: MAX2235
MAX2235 Evaluation Kit
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Quick Start
The MAX2235 EV kit is fully assembled and factory
tested. Follow the instructions in the Connections and
Setup section for proper device evaluation.
Test Equipment Required
This section lists the recommended test equipment to
verify operation of the MAX2235. It is intended as a
guide only, and some substitutions are possible.
• One RF signal generator capable of delivering at
least +10dBm of output power at the operating fre-
quency (HP8648C, or equivalent)
• One RF power sensor capable of handling at least
+20dBm of output power at the operating frequency
(HP8482A, or equivalent)
• One RF power meter capable of measuring up to
+20dBm of output power at the operating frequency
(HP EPM-441A, or equivalent)
• An RF spectrum analyzer that covers the operating
frequency range of the MAX2235 as well as a few
harmonics (HP8561E, for example)
• A power supply capable of up to 1A at +2.7V to
+5.5V
• An optional ammeter for measuring the supply cur-
rent
• Two 50Ω SMA cables
• One SMA 20dB pad
• Network Analyzer (HP8753D, for example) to mea-
sure small-signal return loss and gain (optional)
Connections and Setup
This section provides a step-by-step guide to operating
the EV kit and testing the device’s function. Do not turn
on the DC power or RF signal generators until all
connections are made.
1) Connect a DC supply set to +3.6V (through an
ammeter if desired) to the V
CC
and GND terminals
on the EV kit. Do not turn on the supply.
2) Connect one RF signal generator to the RFIN SMA
connector; do not turn on the generator’s output.
Set the generator for an output frequency of
836MHz at a power level of 0dBm.
3) Connect a 20dB pad to the RFOUT SMA connector
on the EV kit. This is to prevent overloading of the
power sensor and the power meter.
4) Connect a power sensor to the 20dB pad.
5) Connect the power sensor to a power meter. Set the
power meter offset to 20dB and frequency to
836MHz.
6) Turn on the DC supply. The supply current should
read approximately 70mA.
7) Activate the RF generator’s output. The power
meter should read approximately +30dBm. The
supply-current should increase to approximately
600mA.
8) Another method for determining gain is by using a
Network Analyzer (optional). This has the advan-
tage of displaying gain versus a swept-frequency
band, in addition to displaying input and output
return loss. Refer to the Network Analyzer manufac-
turer’s user manual for setup details.
Layout Issues
A good PC board (PCB) is an essential part of an RF
circuit design. The EV kit PCB can serve as a guide for
laying out a board using the MAX2235. Keep traces
carrying RF signals as short as possible to minimize
radiation and insertion loss due to the PCB. Each V
CC
node on the PCB should have its own decoupling
capacitor. This minimizes supply coupling from one
section of the IC to another. A star topology for the sup-
ply layout, in which each V
CC
node on the circuit has a
separate connection to a central V
CC
node, can further
minimize coupling between sections of the IC.