freq (GHz)
S21 (d
B)
0
2
4
6
8
10
12
14
16
-3
-2.5
-2
-1.5
-1
-0.5
0
0.5
Input trace loss: - SE 50-ohm (dB)
Output trace loss: Diff 100-ohm (dB)
Figure 3-2. PCB Trace Loss vs Frequency
3.2 Noise Figure Test Setup
ENR Diode
Spectrum Analyzer or
Noise Figure Analyzer
0°
180°
2:1, Zo = 50
3-dB pad
3-dB pad
(J4)
TRF1208
(J6)
TRF1208 EVM
(J5)
INP
INM
OUTM
OUTP
Hyperlabs HL9402
or similar
Figure 3-3. Noise Figure Test Setup
Use the following guidelines for Noise Figure (NF) measurement:
1. As
shows, the traditional Y-factor method can be used for the NF measurement using a Noise
Diode and a spectrum analyzer (or a Noise Figure Analyzer).
2. While doing the measurement, take into account any RF cable losses to the EVM board. Any external input
attenuator added for matching will result in proportional NF degradation and must be calibrated out in the
measurement.
3. Also, onboard losses of the input traces at the device input pin must be factored into the NF measurement.
4. If the loss after the device output is significant, it is important to factor the output loss into the NF
measurement. Use the
Friis
equation to calculate the Noise Figure of the device from the total measured NF.
Test Setup Diagrams
TRF1208 Evaluation Module
9
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