Texas Instruments TRF0206-SP, User Manual

Page: 10 / 17

3.3 Two-Tone OIP3 Test Setup
Power Splitter/
Combiner
(J4)
TRF0206-SP
(J6)
TRF0206-SP EVM
(J5)
INP
INM
OUTM
OUTP
Mini-circuits
ZN2PD2-14W+
or equivalent
6-dB Pad
6-dB Pad
Power Splitter/
Combiner
0°
180°
3-dB Pad
2:1, Zo = 50
Spectrum Analyzer
3-dB Pad
6-dB
Pad
6-dB
Pad
RF Signal
Gen 1
RF Signal
Gen 2
Hyperlabs
HL9402
or similar
Figure 3-4. OIP3 Test Setup
Use the following guidelines for two-tone OIP3 measurement:
1. As Figure 3-4 shows, combine two signal generator outputs using an in-phase power splitter and combiner.
A 6-dB attenuator is recommended at the signal generator outputs to prevent the generators from talking to
each other and resulting in signal generator IMD3 spurs.
2. Set both the signal generator outputs to a power level and frequency spacing so that it yields the desired
output power (P
OUT
) at the device.
3. It is recommended for the output power level to remain within the linear operation range of the TRF0206-
SP device. For example, if the total desired output power at the device is 8 dBm, then set the signal
generators so that each of the fundamental output power results in 2 dBm per tone. As a general rule, it is
recommended to keep the total output power level approximately 6 to 8 dB lower than the 1-dB compression
point. See the device data sheet for the output power levels supported by the device.
4. For the OIP3 test, the two tones can be spaced by the specified frequency.
5. Set the spectrum analyzer attenuation setting appropriately so that the spectrum analyzer non-linearity does
not affect the measurements.
6. Keep spectrum analyzer RBW and VBW settings identical for main tone and IM3 products.
7. For output IP3 calculation, take into account combined losses at the desired frequency band between the
TRF0206-SP device output to the spectrum analyzer input. The combined power loss is due to PCB output
trace, RF coax cable, 0/180° passive balun, and any attenuator pad used for external matching purposes.
The calculated OIP3 is given in
Equation 1 .
Output IP3 = (P
IN_SA
– IMD3) / 2 + P
IN_SA
+ P
LOSS
(1)
where,
• P
IN_SA
= Input power per tone into the spectrum analyzer
• P
LOSS
= Power loss from the device output to the spectrum analyzer input
• IMD3 = Higher power of the two intermodulation distortion products recorded at either 2f1 – f2 or 2f2 – f1
8. In Equation 1 , P
IN_SA
+ P
LOSS
= P
OUT
is the amplifier output power per tone.
Test Setup Diagrams www.ti.com
10 TRF0206-SP Evaluation Module SLAU877 – OCTOBER 2022
Submit Document Feedback
Copyright © 2022 Texas Instruments Incorporated