PGA-105+: Stabilizing Network

The PGA-105+ is a 15dB gain monolithic amplifier for the 40-2600MHz range with excellent gain flatness and a high dynamic range (1dB compression point: 19.3dBm @ 2GHz).

S parameters for the PGA-105+ can be found here. Unconditional stability requires stability factor k>1 and stability measure B>0. However, an analysis of the S-parameters shows the amplifier has k<1 for frequencies under 60MHz.

In order to improve stability, addition components need to be added at input and output, see Figure 2:

The stability parameters of the amplifier with the stabilizing network are shown in Figure 3. Note: k>1 and B>0 over entire range.

The stabilized amplifier has an amplification of about 14.5 dB

The performance of the stabilized amplifier:

Conclusion

• Use of the stabilization circuitry has minor impacts on all parameters
• The use of the stabilization circuitry guarantees amplifier's unconditional stability.