Quick Start

Recommended Equipment

• One variable DC power supply capable of supplying

between 2.7V and 5.5V at 50mA

• One signal generator capable of delivering -35dBm

to +10dBm at frequencies between 900MHz and

2.5GHz

• One voltmeter

Procedure

The MAX4001 EV kit is fully assembled and tested.

Follow the steps below to verify board operation. Do

not turn on the power supply until all connections

are completed:

1) Set the variable DC power supply to 3V.

2) Ensure that the variable DC power supply is turned off.

3) Connect the positive terminal of the variable DC

power supply to the pad marked VCC. Connect the

ground return of the variable DC power supply to

the pad marked GND.

4) Set the signal generator to produce an output sig-

nal of 0dBm at a frequency of 2.5GHz.

5) Ensure that the signal generator is turned off.

6) Connect the signal generator to the edge-mount

SMA connector marked RFIN.

7) Connect the positive terminal of the voltmeter to the

pad marked SET. Connect the ground return of the

voltmeter to the pad marked GND.

8) Ensure that shunts are installed across jumpers JU1

and JU2.

9) Ensure that a shunt is placed across pin 1 and pin

2 of jumper JU3.

10) Turn on the variable DC power supply.

11) Turn on/enable the output of the signal generator.

12) Verify with the voltmeter that an output voltage of

1.2V (±5%) is produced between the SET pad and

the GND pad.

Detailed Description

The MAX4001 EV kit is a fully assembled and tested

surface-mount circuit board that evaluates the

MAX4001 RF-detecting controller. The MAX4001 EV kit

includes on-board shutdown control as well as quasi-

measurement mode circuitry to provide an easy

method to evaluate the MAX4001. The RF input utilizes

a 50

Ω SMA connector for convenient connection to test

equipment. The MAX4001 EV kit can also be used to

evaluate the MAX4000 and MAX4002 RF-detecting

controllers.

For operation in controller mode, both JU1 and JU2

should be removed. Use a DAC or external precision

voltage supply to apply the set-point voltage to the SET

pad. Connect the RF source (the Power Amplifier (PA)

output through a directional coupler) to the RFIN SMA

connector. Connect the gain control pin of the PA to the

OUT pad. When used in controller mode, a capacitor

(C4) must be present for loop stability (see the Filter

Capacitor Selection section).

To simulate an Automatic Gain-Control (AGC) loop, a

quasi-measurement mode can be implemented where

the MAX4001 delivers an output voltage that is propor-

tional to the log of the input signal (see the Quasi-

Measurement Mode section). To establish the transfer

function of the log amp, the RF input power level should

be swept while the voltage at the SET pad is measured.

This is the simplest method to validate operation of the

evaluation board.

Shutdown Control

Jumper JU3 controls the CMOS-compatible shutdown

pin (SHDN) of the MAX4001, which disables the

MAX4001. Removing the shunt from JU3 allows the

SHDN pin to be driven with an external signal source

connected to the SHDN pad (see Table 1 for shutdown

shunt positions).

Quasi-Measurement Mode

Enabling the quasi-measurement mode changes the

MAX4001 EV kit function from a PA controller to a log

detector. This mode allows for easy measurement of

RFIN versus the SET voltage and these measurements

can then be used to find the intercept and slope

required for the given application.

Placing shunts across JU1 and JU2 enables the quasi-

measurement mode (which connects the OUT voltage

through an inverting op amp to the SET pin). The quasi-

measurement mode yields a nominal relationship

between RFIN and SET (see Table 2 for quasi-mea-

surement mode shunt positions).

MAX4001 Evaluation Kit

2

_______________________________________________________________________________________

JUMPER

SHUNT

POSITION

DESCRIPTION

1–2

MAX4001 enabled

2–3

MAX4001 disabled

JU3

Not Installed

SHDN pin driven by an

external signal source

Table 1. Shutdown Selection