2N5109 RF Amplifier 10MHz NF

Amplifier Design Description

OIP3 versus Input Power

Emitter Current = 19mA Rigol DG1032Z Output = 4.97MHz and 5.03MHz LPF Rigol DG1032Z Output = 8.03MHz and 12MHz VNWA in Spectrum Analyzer mode Two Configurations: DG1032Z -> 3dB Coupler -> -4dB -> DUT > -40dB -> VNWA Port 2 DG1032Z -> 3dB Coupler -> -4dB -> DUT > -20dB -> LPF -> VNWA Port 2 Theoretical OIP3 = 20*log10(((19/1414)**2)*200000) = 31.2dBm

RFD-2315 NF Measurement

RFD-2315 ENR at 10MHz = 15.6dB RFD-2315 ENRratio = 10^(15.6 / 10) = 36.31 DUT Tc = -83.3dB, Th = -70.6dB, Delta = 12.7dB Y = 10^(12.7 / 10) = 18.62 NF = ENRratio / (Y - 1) NF = 36.31 / (18.62 - 1) = 2.06 NFdB = 10 * log(2.06) = 3.14dB ENR=15.6dB YdB to NF chart

HP-346C NF Measurement

HP-346C ENR at 10MHz = 12.97dB HP-346C ENRratio = 10^(12.97 / 10) = 19.815 DUT Tc = -83.4dB, Th = -73.3dB, Delta = 10.1dB Y = 10^(10.1 / 10) = 10.233 NF = ENRratio / (Y - 1) NF = 19.815 / (10.233 - 1) = 2.146 NFdB = 10 * log(2.146) = 3.32dB ENR=12.97dB YdB to NF chart

OIP3

OIP3 = -1.9 + ((62.3 - 1.9) / 2) = 28.3dBm

VNWA Spectrum Analyzer Calibration

Rigol DG1032 -30dBm + 40dB Attenuator VNWA 2000 Points, 200 seconds 40kHz bandwidth

N-Gen Measurement

External 12.0VDC Power Source Noise Power = -75.83 dBm

Compute N-Gen with 40 dB Attenuator ENR

Effective BW = 50kHz Shape factor noise under response ~ 2.5dB ENR = 10^((-75.83 + 2.5 - 30 - 40) / 10)/(290 * k * 50k) - 1 = 22.2 = 13.46dB k = 1.38065e-23 Boltzman constant

LNA + VNWA Noise Figure

Tc = -98.7dB, Th = -89.8dB, Delta = 8.9dB Y = 7.76 NF = 22.2 / (7.76 - 1) = 3.28 = 5.16dB

DUT + LNA + VNWA Noise Figure

Tc = -83.5dB, Th = -72.7dB, Delta = 10.8dB Y = 12.02 NF = 22.2 / (12.02 - 1) = 2.01 = 3.04dB

Subtract LNA + VNWA NF

Gain at 10MHz = 17.2dB = 52.5 NFDUT = 2.01 - ((3.28 - 1) / 52.5) = 1.97 = 2.94dB

HP-346C and N-Gen+40 Comparison

30dB LNA Preamplifier with VNWA HP-346C 10MHz NF = 12.97dB = 19.8153 LNA+VNWA noise power = (10*Log((19.8153 + 1)*290*k*50k)) + 30 - 2.5 = -116.3 VNWA bandwidth = 40k LNA+VNWA calibrated to match -116.3dBm marker 2. N-Gen+40, Marker 1 = -115.82dBm VNWA measured noise power Above = -75.83 - 40 = -115.83dBm

NF Measurement using DUT Noise Power

Using above LNA + VNWA dBm calibration NF = N - GDUT - 10log(B) + 174dB + FSF N = noise power = -109.45 GDUT = DUT Gain = 17.2dB B = Bandwidth in Hz = 50kHz FSF = Filter Shape Factor = 2.5dB NF = -109.45 - 17.2 - 10log(50k) + 174dB + 2.5 = 2.86dB

Wellbrook Dynamic Impedance Method
Input Terminated and Nonterminated Measurement

Wellbrook Reference Using above LNA + VNWA dBm calibration Delta dB = -110.14 - -109.4 = 0.74dB "LNA noise difference to Noise Temp and Noise Figure" chart, NF between 2.54 and 3.00