MAX2338 Evaluation Kit

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3

Low-Noise Amplifier, High-Gain

High-Linearity Mode

(HIGH). This enables the LNA to operate in high

gain mode.

(HIGH) to test cellular band [JU1 to GND for PCS].

(HIGH) to test the amplifiers in high linearity mode.

4) Connect a DC supply preset to +3V (through an

terminals. Do not turn on the supply.

5) Perform a full two-port calibration on a network ana-

lyzer at a power level of -30dBm over frequency

range of 800MHz to 900MHz for cellular band

[1900MHz to 2000MHz for PCS band].

6) Connect port 1 and port 2 of the network analyzer to

CLNAIN [PLNAIN for PCS] and CLNAOUT

[PLNAOUT for PCS] respectively to measure the

cellular [PCS] band gain.

7) Turn on the DC supply. If an ammeter is connected,

the supply current should read approximately 28mA

for cellular band [25mA for PCS].

8) The network analyzer display should indicate a typi-

cal gain of 15.7dB for cellular band and 15.3dB for

PCS band after accounting for board losses. The

input and output board losses are 0.12dB for the

cellular band. The input and output board losses for

PCS band are 0.17dB and 0.3dB, respectively.

These losses are to be added to the measurements

to obtain the performance of the LNAs.

Downconverter

1) Turn off the DC supply.

2) Remove the network analyzer from the LNA input

and output connections. The DC supply connec-

tions needed for testing the downconverter mixer

are the same as in the LNA section.

the LO divider circuit for cellular band. When testing

PCS band, this jumper setting has no effect.

(HIGH) to test cellular band [JU1 to GND for PCS].

(HIGH) to test cellular and PCS downconverters in

high-linearity mode.

6) Connect an RF signal generator (with output dis-

abled) to the LOIN connector. Set the frequency to

2126MHz for cellular band [2143MHz for PCS] and

the output power to -3dBm.

7) Connect another RF signal generator (with output

disabled) to the CMIXIN SMA connector. Set the

frequency to 880MHz for cellular band [1960MHz

for PCS band] and the output power to -25dBm.

8) Connect the spectrum analyzer to the IFOUT SMA

connector. Set the spectrum analyzer center fre-

quency to 183MHz.

9) Turn on the DC supply. Enable the LO signal gener-

ator and RF input signal generator outputs.

10) Measure the peak of the 183MHz IF signal on the

spectrum analyzer. Compensate the IF signal con-

version gain for the balun and board losses. Balun

loss is 0.3dB and the input and output board losses

are 0.1dB each.

11) The conversion gain for cellular and PCS band are

typically +13.3dB and +14.5dB respectively, after

corrections from step 10 are applied.

Checking Noise Figure

Noise figure measurements are 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 goes beyond

the scope of this document. For more information on

how to perform this level of noise figure measurement,

refer to the noise figure meter operating manual, as well

as to Hewlett Packard application note #57-2, Noise

Figure Measurement Accuracy.

PC Board Layout Considerations

The MAX2338 EV kit can serve as a board layout guide.

Keep PC board trace lengths as short as possible to

minimize parasitics. Keep decoupling capacitors close

to the device, with a low inductance connection to the

ground plane.