Using Avago's MSA Series MMIC Amplifiers as Frequency Converters - App Note

Avago Technologies' MSA Series amplifiers can be used as the active element for an oscillator at frequencies up to 8 GHz or as a mixer with gain for RF input frequencies up to 9 GHz or as a self-contained frequency converter (self-oscillating mixer). As a mixer, these devices can be used as either upconverters or downconverters while providing conversion gain for RF signals up to 9 GHz. Figure 1 shows typical conversion gain vs. frequency for two models configured for active frequency conversion along with the associated functional RF schematic and block diagram. MSA series devices are available in a variety of metal, ceramic and low-cost plastic stripline packages for military, commercial and consumer applications. The monolithic microwave integrated circuit (MMIC) used in the frequency converter consists of a silicon bipolar Darlington pair with associated bias resistors. It is fabricated using a 10 GHz ft nitride self-aligning process featuring ion implantation and thin film poly-silicon resistors. The geometry incorporates inter-digitated sub-micron-width emitter fingers with an emitter pitch of 4 microns, the centerline distance between adjacent emitter fingers. The circuit schematic for the frequency converter Darlington pair is shown within the dotted lines in Figure 1a.