if_amp

__IF Amplification__

For the intermediate frequency amplifiers, the RF2312 was used. It is an amplifier designed specifically for use after a low noise amplifier, and provides high gain with high IIP3, helping to maximize dynamic range and minimize system noise. The schematic for this amplifier is shown in Figure 4.3.1.

Figure 4.3.1 – IF Amplifier The four resistors in parallel are designed to maintain the required biasing resistance of 30 Ohms while allowing for a greater current path (minimize individual power dissipation). The amplifier resistance is chosen for biasing was 30 Ohms based on the device current of 120 mA, and the nominal device voltage of 5.5V. The RF choke inductance and input/output capacitance were chosen based on results from AppCAD (see Figure 4.3.2). Figure 4.3.2 – AppCAD Results