RF3330PCBA-41X データシートの表示（PDF） - RF Micro Devices

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RF3330PCBA-41X

IF GAIN CONTROLLED AMPLIFIER

RF Micro Devices 

RF3330

offset needs to be applied to the signal generator. The formulas used to calculate this offset are given below in Equations 1

through 3. It should be noted that the unbalanced 1000Ω load is used, because all data in the datasheet is referenced to sin-

gle-ended operation. Using a spectrum analyzer probe, the actual offset measured was 7.5dB, and this is what is used for the

amplitude offset in the signal generator.

Mismatch Loss (ML)=-10*log(1-|ΓL|2)Eq. 1

ΓL =(Z-Z0)/(Z+Z0)Eq. 2

ML = -10 * log (1 - [(1000 -50) / (1000+50)]2) = 7.4 dB

Eq. 3

Output

On the output, the losses due to the resistive matching pad must also be calibrated out of the setup. Because of the 1:1 trans-

former, the spectrum analyzer appears as a 50Ω resistor in parallel with this circuit (see Figure 2). Equation 4 illustrates the

calculation necessary to obtain the amount of loss due to this matching circuit. The balun also has an additional 0.5dB to

1.0dB of loss, which is added in to the overall output losses. This was verified with a spectrum analyzer probe. The offset used

in the test setup is 32.5dB on the spectrum analyzer.

Resistive Pad Loss=

20*log(25/(470+25+470))=-31.7dBEq. 4

Frequency =

1 MHz to

150 MHz

Frequency =

1 MHz to

150 MHz

Signal Generator

Mini-Circuits

ZMSCJ-2-1

Divider

Figure 1. RF3330 Test Setup

RF3330

Resistive

Match

1:1

Transformer

Frequency =

1 MHz to

150 MHz

3330410 Evaluation Board

Spectrum Analyzer

R4

470 Ω

R3

51 Ω

50 Ω

R2

470 Ω

Figure 2. Equivalent Output Circuit

8 of 10

7628 Thorndike Road, Greensboro, NC 27409-9421 · For sales or technical

support, contact RFMD at (+1) 336-678-5570 or sales-support@rfmd.com.

Rev A4 DS060908

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