TEST PROCEDURE FOR POWER AMPLIFIER

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TEST PROCEDURE FOR

POWER AMPLIFIER

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1. SCOPE ...4

2. TEST EQUIPMENT ...5

3 Test Procedure ...13

3.1 1dB Compression Point (P1dB) Test ...13

3.2 Third Order Intercept Point (OIP3) Test ...14

3.3 Noise Figure (NF) Test ...15

3.3.1 Calibration...15

3.3.2 Measurement ...16

3.3.3 Calculation ...17

3.5 Output Power and Frequency Range Test ...18

3.6 Small Signal Gain Test ...19

3.7 Power Added Efficiency (PAE) Test ...20

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Figure Page

1 Test Flow Diagram ...6

2 P1dB Test Setup ...7

3 OIP3 Test Setup ...8

4a Noise Figure Test Setup (calibration) ...9

4b Noise Figure Test Setup (measurement) ...9

6 Output Power and Frequency Range Test Setup ...10

7 Output Power vs. Frequency vs. Input Power (QORVO reference) ...11

8 Gain vs. Frequency vs. Bias Voltage (QORVO reference) ...11

9 PAE Test Setup ...12

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The main objective of the tests delineated in the procedure is to verify the functional performance of the Power Amplifier in accordance with the requirements stipulated by Ryan.

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2. TEST EQUIPMENT

Item Description Manufacturer Model

1. Network Analyzer 2. RF Signal Generator 3. Power Meter

4. Noise Source 5. Spectrum Analyzer 6. Ammeter

9. Voltmeter

11. 10dB 100W Attenuator 15. Two-Way Power Splitter 19. DC Power Supply

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Figure 1. Test Flow Diagram 1 dB compression point

(P1dB)

Noise Figure (NF)

Third Order Intercept Point (OIP3)

Adjacent Channel Power Ratio (ACPR)

Output Power and Frequency Range

Small Signal Gain

Power Added Efficiency (PAE)

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Figure 2. P1dB Test Setup RF

Signal Generator

10 dB Attenuator

DUT

Power Meter

INPUT

OUTPUT

Power Supply(s)

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Figure 3. OIP3 Test Setup RF

Signal Generator

RF Signal Generator

2-Way Power Splitter

DUT

Spectrum Analyzer

Power Supply(s)

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Figure 4a. Noise Figure Test Setup (Calibration)

Figure 4b. Noise Figure Test Setup (Measurement) Noise Source

Spectrum Analyzer

Noise Source

Spectrum Analyzer

DUT

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Figure 5. Output Power and Frequency Range Test Setup RF

Signal Generator

Power Meter (input power)

DUT

Power Meter (output power)

Power Supply(s)

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Figure 6. Output Power vs. Frequency vs. Input Power (QORVO reference)

Figure 7. Gain vs. Frequency vs. Bias Voltage (QORVO reference)

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Figure 8. PAE Test Setup RF

Signal Generator

Power Meter (input RF power)

DUT

Power Meter (output RF power)

DC Power Supply A

V

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3.1 1dB Compression Point (P1dB) Test

Step Parameter

Stamp/Date

1. PLEASE OBSERVE ESD PRECAUTIONS THROUGHOUT PROCEDURE.

_________

2. With all instruments turned on and their outputs turned off, construct the test setup shown in Figure 2. Don’t connect RF cables to the DUT yet. Initially, the 10dB

attenuator should be set to 0dB attenuation. _________

3. Set the output frequency of the RF Signal Generator to an in-band frequency for the DUT and set the output power to the device’s minimum. Don’t turn the supply’s output on yet. E-calibrate the RF Signal Generator to the cables before attaching the

cables to the DUT. Finish setup assembly by connecting the RF cables to the DUT. _________

4. Using a DC power supply, supply the DUT’s bias points with the specified voltages and limit the current slightly below the DUT’s specified max current.

_________

5. Turn on the RF Signal Generator output at its minimum output power and observe the

reading on the power meter in dBm. _________

6. Turn the attenuator up to 10dB attenuation and observe the change in power read on

the power meter in dBm from beginning to end. _________

7. If the change in power observed on the power meter is more than 9dBm, increase the output power of the RF power supply and repeat step 6.

If the change in power observed on the power meter is less than 9dBm, decrease the output power of the RF power supply and repeat step 6.

If the change in power observed on the power meter is equal to 9dBm, record the output power of the RF power supply in datasheet because that’s the P1dB point.

_________

8. If necessary, repeat steps 5 – 7 several times to assert reliability of measurement.

P1dB can vary with frequency so one might want to repeat this measurement at

various in-band frequencies to test the entire bandwidth of the DUT. _________

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Stamp/Date

_________

2. With all instruments turned on and their outputs turned off, construct the test setup

shown in Figure 3. Don’t connect RF cables to the DUT yet. _________

3. Set the output frequency of one of the RF Signal Generators to an in-band frequency for the DUT. Set the output frequency of the other RF Signal Generator to a frequency close to (or approximately 1% away from) the first frequency. Set the output power of both Signal Generators to their minimums. Don’t turn the Signal Generators on yet. E- calibrate the Signal Generators to the cables before attaching the cables to the DUT.

Finish setup assembly by connecting the RF cables to the DUT. _________

_________

5. Set the output power of both RF Signal Generators to a value less than one quarter of the DUT’s rated maximum input power. Using the power readings on the Spectrum Analyzer, tune the RF signal generators until the same power is observed at each frequency. There should also be two new frequencies observed on the Spectrum

analyzer to the right and left of the two input frequencies. These are the IM3 products. _________

6. Record the power (P0) of the two RF Signal Generators observed on the Spectrum Analyzer in dBm. Record the Power (IM3) of the IM3 products in dBm. Record the

difference (IMD3) between the recorded IM3 value and the recorded P0 value. _________

7. Finally, 𝑂𝐼𝑃3 = ^{𝐼𝑀𝐷3}₂ + 𝑃₀ . Record the value of OIP3.

_________

8. If OIP3 ≠ P1dB + 10, a mistake was made in one of the measurements and both measurements should be repeated. If necessary, repeat steps 5 – 7 several times to

assert reliability of measurement. _________

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3.3.1 Calibration

Step Parameter

Stamp/Date

_________

2. Connect the equipment as shown in Figure 4a. Connect the output of the noise source to the RF input of the spectrum analyzer. Connect the noise source control of the

spectrum analyzer to the noise source. _________

3. Set the spectrum analyzer to the desired test frequency. Set the RBW to be less than the BW of the DUT. Enable the preamplifier in the spectrum analyzer. Set the RF attenuator to 0dB. Set the reference level to a low value (-80dB). Set the Log range to a low value (30dB). Select the RMS detector. Select a slower sweep time (1s) to RMS

average the results. _________

4. Observer or calculate the following values for the noise source:

𝑇_{𝑠𝑜𝑢𝑟𝑐𝑒}^𝑂𝐹𝐹 = 𝑇₀, 𝑇_{𝑠𝑜𝑢𝑟𝑐𝑒}^𝑂𝑁 = 𝑇₀( 1 + 10^𝐸𝑁𝑅¹⁰ )

5. Turn the Noise Source off and measure 𝑁_𝑜𝑓𝑓^𝑆𝐴 and 𝑁_𝑜𝑛^𝑆𝐴 in Watts (not dBm).

Calculate the linear Y-factor of the Spectrum Analyzer 𝑌_𝑆𝐴 =_𝑁^𝑁^𝑜𝑛^𝑆𝐴

𝑜𝑓𝑓𝑆𝐴

_________

6. Solve for the noise temperature of the Spectrum Analyzer:

𝑇_𝑆𝐴=𝑇_{𝑠𝑜𝑢𝑟𝑐𝑒}^𝑂𝑁 − 𝑌_𝑆𝐴∗ 290

𝑌_𝑆𝐴− 1 _________

7. Finally, convert the noise temperature of the Spectrum Analyzer into a noise figure:

𝑁𝐹_𝑑𝐵^𝑆𝐴 = 10 log ( 𝑇_𝑆𝐴

𝑇₀ − 1) = 𝐸𝑁𝑅_𝑑𝐵− 10log ( 𝑌_𝑆𝐴− 1)

_________

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Stamp/Date

1. Connect the DUT between the Noise Source and the Spectrum Analyzer as shown in

Figure 4b. _________

2. Turn the noise source off and measure the noise power of 𝑁_𝑜𝑓𝑓^{𝐷𝑈𝑇+𝑆𝐴} and 𝑁_𝑜𝑛^{𝐷𝑈𝑇+𝑆𝐴} in

Watts. _________

3. Calculate Y factor for the DUT and SA combined:

𝑌_{𝐷𝑈𝑇+𝑆𝐴}= 𝑁_𝑜𝑛^{𝐷𝑈𝑇+𝑆𝐴}

𝑁_𝑜𝑓𝑓^{𝐷𝑈𝑇+𝑆𝐴} _________

4. Solve for the noise temperature of the DUT and SA combined:

𝑇_{𝐷𝑈𝑇+𝑆𝐴} =𝑇_{𝑠𝑜𝑢𝑟𝑐𝑒}^𝑂𝑁 − 𝑌_{𝐷𝑈𝑇+𝑆𝐴}∗ 290 𝑌_{𝐷𝑈𝑇+𝑆𝐴}− 1

5. Finally, convert the noise temperature of the cascade into a noise figure:

𝑁𝐹_𝑑𝐵^{𝐷𝑈𝑇+𝑆𝐴}= 10 log ( 𝑇_{𝐷𝑈𝑇+𝑆𝐴}

𝑇₀ − 1) = 𝐸𝑁𝑅_𝑑𝐵− 10log ( 𝑌_{𝐷𝑈𝑇+𝑆𝐴}− 1)

_________

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Step Parameter

Stamp/Date

1. Calculate the linear gain of the DUT:

𝐺𝑎𝑖𝑛_𝐷𝑈𝑇 = 10log [𝑁_𝑂𝑁^{𝐷𝑈𝑇+𝑆𝐴}− 𝑁_𝑂𝐹𝐹^{𝐷𝑈𝑇+𝑆𝐴} 𝑁_𝑂𝑁^𝑆𝐴− 𝑁_𝑂𝐹𝐹^𝑆𝐴 ]

_________

2. Calculate the noise temperature of the DUT:

𝑇_𝐷𝑈𝑇 = 𝑇_{𝐷𝑈𝑇+𝑆𝐴}− 𝑇_𝑆𝐴

𝐺𝑎𝑖𝑛_𝐷𝑈𝑇 _________

3. Calculate the Noise Figure of the DUT:

𝑁𝐹_𝑑𝐵 = 10log [ 𝑇_𝐷𝑈𝑇 290 + 1]

_________

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Step Parameter

Stamp/Date

_________

2. With all instruments turned on and their outputs turned off, construct the test setup

shown in Figure 5. Don’t connect RF cables to the DUT yet. _________

3. Set the output frequency of the RF Signal Generators to a low, out of band frequency for the DUT and set the output power to the device’s minimum. Don’t turn the Signal Generator on yet. E-calibrate the Signal Generator to the cables before attaching the

4. Using a DC power supply, supply the DUT’s bias points with the specified voltages and limit the current slightly below the DUT’s specified max current. Record the values of these biases for the graph which will be produced later.

_________

5. Turn on the RF Signal Generator’s output and set the output power to a value less than the DUT’s rated maximum input power and use the first Power Meter in the signal

chain to measure and record the input power the DUT sees. _________

6. Use the signal generator and the second power meter to record the values of the input frequency and output power (with respect to the DUT) while sweeping the RF Signal

Generator’s output frequency from below the DUT band to above the DUT band. _________

7. The values recorded in step 6 should produce a line displaying output power as a function of input frequency. This line is associated with a specific input power.

_________

8. Repeat steps 5-6 with various input powers (all less than the device’s rated maximum

input power and preferably 1dBm apart) and record all the lines produced on one plot. _________

9. If done correctly, the plot produced should look somewhat like the plot in Figure 7.

Output power and frequency range both depend on several other variables (including input power) so a plot like the one in Figure 7 is useful for estimating the output

power you can expect at various frequencies. _________

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3.5 Small Signal Gain Test

Step Parameter

Stamp/Date

_________

2. With all instruments turned on and their outputs turned off, construct the same setup used to test output power and frequency range (seen in Figure 5). Don’t connect RF

cables to the DUT yet. _________

3. Set the output frequency of the RF Signal Generators to a low, out of band frequency for the DUT and set the output power to the device’s minimum. Don’t turn the Signal Generator on yet. E-calibrate the Signal Generator to the cables before attaching the

4. Using a DC power supply, supply the DUT’s bias points with the specified voltages and limit the current slightly below the DUT’s specified max current. Record the values of these biases for the graph which will be produced later.

_________

5. Turn on the RF Signal Generator’s output and set its output power to a dBm which is substantial compared to the DUT’s NF but stay considerably below the DUT’s P1dB

point to remain in the linear region. _________

6. Use the power meters to record the values of the input power and output power (with respect to the DUT) in dBm and divide the output power by the input power to

calculate the gain in dB. Calculate the gain of the DUT repeatedly while sweeping the RF Signal Generator’s output frequency from below the DUT band to above the DUT

band. _________

7. The values recorded in step 6 should produce a line displaying gain as a function of frequency. This line is associated with a specific bias voltage.

_________

8. Repeat steps 5-6 with various bias voltages (vary the voltage of whichever bias is relevant to the DUT without exceeding rated ranges) and record all the lines produced

on one plot. _________

9. If done correctly, the plot produced should look somewhat like the plot in Figure 7.

Gain is not an absolute term so it’s helpful to see it at various frequencies and bias

voltages. _________

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3.6 Power Added Efficiency (PAE) Test

Step Parameter

Stamp/Date

_________

2. With all instruments turned on and their outputs turned off, construct the test

setup seen in Figure 8. Don’t connect RF cables to the DUT yet. _________

3. Set the output frequency of the RF Signal Generators to an in-band frequency for the DUT and set the output power to the device’s minimum. Don’t turn the Signal Generator on yet. E-calibrate the Signal Generator to the cables before attaching the cables to the DUT. Finish setup assembly by connecting the RF

cables to the DUT. _________

Notice that an ammeter should be connected in series before a voltmeter connected in parallel to measure current and voltage.

_________

5. Turn on the RF Signal Generator’s output and set its output power to whichever

dBm is important (linear region, max power, etc.). _________

6. Use the power meters to record the values of the input power and output power (with respect to the DUT). Convert the values of input power and output power to watts. Additionally, record the values read on the ammeter and voltmeter. Use

the ammeter and voltmeter readings to record DC Input Power = IV. _________

7. Using the recorded values, calculate PAE using the following equation:

𝑃𝐴𝐸 =𝑅𝐹 𝑂𝑢𝑡𝑝𝑢𝑡 𝑃𝑜𝑤𝑒𝑟 [𝑊] − 𝑅𝐹 𝐼𝑛𝑝𝑢𝑡 𝑃𝑜𝑤𝑒𝑟 [𝑊]

𝐷𝐶 𝐼𝑛𝑝𝑢𝑡 𝑃𝑜𝑤𝑒𝑟 [𝑊]

_________

8. PAE is also dependent on RF Input Power and frequency so one could measure PAE repeatedly while sweeping one of those variables to produce plots similar

to those seen in Figure 6 and figure 7. _________