output. Connect the RF generator output to the RFIN

SMA connector with a coaxial cable.

3) Connect the coaxial cable from the RFOUT SMA

connector to the spectrum analyzer.

4) Turn on the DC supply. The supply current should

read approximately 10mA (if using an ammeter).

5) Activate the RF generator’s output. A signal on the

spectrum analyzer’s display should indicate a typi-

cal gain of +17dB after accounting for cable and

board losses. Typical board loss is 0.6dB from input

to output port.

6) (Optional) Another method for determining gain is

using a network analyzer. This has the advantage of

displaying gain versus a swept frequency band, in

addition to displaying input and output return loss.

Refer to the network analyzer manufacturer’s user

manual for setup details.

Checking Noise Figure

Noise figure measurements on low-noise devices such

as the MAX2644 are extremely sensitive to board and

lab setup losses and parasitics. There are many tech-

niques and precautions for measuring a low noise fig-

ure. Detailed explanation of these items would exceed

the scope of this document. Take into account PC-

board and external-components loss when performing

noise-figure measurements. The typical input losses on

this EV kit are 0.3dB. For more information on how to

perform this level of noise-figure measurement, refer to

the noise-figure meter operating manual as well as the

Agilent Technologies (formerly Hewlett Packard) appli-

cation note #57-2, “Noise Figure Measurement

Accuracy.”

Layout Considerations

A good PC board layout is an essential part of an RF

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

guide for laying out a board using the MAX2644.

a decoupling capacitor located close to the device,

lines. This minimizes supply coupling. Proper ground-

ing of the GND pins is essential. Connect the GND pins

to the ground plane either directly or through vias or

both.

MAX2644 Evaluation Kit

2

_______________________________________________________________________________________

U1

MAX2644

SMA

RFIN

SMA

RFOUT

C1

33pF

L1

3.3nH

3

2

1

R1

1.2k

Ω

6

5

4

GND

C3

2.2pF

C2

33pF

VCC

GND

RFIN

GND

RFOUT

BIAS

Length = 400mils

Figure 1. MAX2644 EV Kit Schematic