Filter Capacitor Selection

When functioning as a PA controller, the MAX4001

requires some capacitance to maintain loop stability.

Global System for Mobile (GSM) applications require a

control-loop bandwidth of at least 150kHz. A 2200pF

capacitor, C4, is installed to obtain this control-loop

bandwidth. Refer to the Gain and Phase vs. Frequency

graph in the Applications Information section of the

MAX4000/MAX4001/MAX4002 data sheet for alternative

capacitor values.

Evaluating the MAX4000/MAX4002

Evaluating the MAX4000

The MAX4001 can be replaced with the MAX4000 to

allow an input range of -45dBm to 0dBm into 50

Ω. The

modifications required are as follows:

1) Replace U1 with a MAX4000EBL.

2) Replace C6 with a 0

Ω (0402) resistor.

Evaluating the MAX4002

The MAX4001 can be replaced with the MAX4002 to

allow an input range of -30dBm to +15dBm in 50

Ω. The

modifications required are as follows:

1) Replace U1 with a MAX4002EBL.

Layout Considerations

A good PC board is an essential part of RF circuit

design. The MAX4001 EV kit PC board can serve as a

guide for laying out a board using the MAX4000/

MAX4001/MAX4002. Keep traces carrying RF signals

as short as possible to minimize radiation and insertion

loss due to the PC board. Each VCC node on the PC

board should have its own decoupling capacitor. This

minimizes supply coupling from one section of the PC

board to another. Using a star topology for the supply

layout, in which each VCC node in the circuit has a

separate connection to the central VCC node, can fur-

ther minimize coupling between sections of the PC

board.

MAX4001 Evaluation Kit

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3

JUMPER

SHUNT

POSITION

DESCRIPTION

Installed

Quasi-measurement mode

enabled

JU1, JU2

Not Installed

Quasi-measurement mode

disabled

Table 2. Quasi-Measurement Mode

Selection