PP Amplifier Design

Additional Design Notes

T1 = 5:5:5 Trifilar Turn BN43-202 T2 = 7:7:5Tap Bifilar Turn BN73-302 Q1,Q2 = BFQ19 R1,R2 = 1500Ω R3 = 680Ω R6,R9 = 12Ω R8 = 100Ω C1,C3,C4 = 1uF C5 = 4.7uF C6 = 0.01uF L1 = 47uH FB3,FB4 = FB43-101 Vcc = 12.0V Idle Vr8 = 4.47 = 45.8mA = 22.9mA/Transistor

Oscilloscope
Output set to maximum sign wave Pout (Blue) ~= P1dB = 3.027Vrms = 0.1833W = +22.63dBm Per Transistor Load = 196Ω Transistor collector Vrms (Red) = 12.72 / 2 / 1.414 = 4.498Vrms Per Transistor Power (Voltage) = 4.498^2 / 196 = 0.103W Per Transistor Power (Current) = 0.0229^2 * 196 = 0.103W Measured OIP3 = +38dBm

VNWA Input Z and Gain

Compute R1,R2 Value
Ic = Transistor current in mA RE = External emitter resistance Rs = Transistor Input (source) Impedance Rl = Transistor Output (load) Impedance Rf = Computed Feedback Resistor value Rf = (Rs × Rl) / (RE + (26 / Ic)) Example: (100 × 196) / (12 + (26 / 23)) = 1493Ω

Resistor Values
	23mA	30mA	40mA	50mA
Tested configuration, 19dB gain R3=680 R4=NoPop R6/9=12 R5/7=NoPop
R1/2	1500
R8	100
Nominal 20dB gain R3=680 R4=NoPop R6/9=12 R5/7=NoPop
R1/2		1500	1600	1600
R8		75	51	39
Nominal 23dB gain R3=680 R4=NoPop R6/9=12 R5/7=22
R1/2		2200
R8		30
Nominal 23dB gain R3=1200 R4=NoPop R6/9=12 R5/7=22
R1/2		2200
R8		47
Nominal 25dB gain R3=1800 R4=NoPop R6/9=12 R5/7=12
R1/2				3000
R8				47

T1 Input Z Primary Turn Count Turns:5:5
Zin	Turns
128	8
98	7
72	6
50	5
32	4
18	3
8	2

Low NF 2SC5551 Design

Q1 Q2 = 2SC5551 50mA per Transistor HP NF meter, 10Mc: +22.04 dB gain, 2.42 dB NF OIP3 = +44dBm OIP2 = +79dBm

Boards

Previous Design Notes