The HMC521ALC4 is a compact, gallium arsenide (GaAs), monolithic microwave integrated circuit (MMIC), inphase quadrature (I/Q) mixer in a RoHS compliant, 24-terminal ceramic leadless chip carrier (LCC) package. This device can be used as either an image reject mixer or a single sideband upconverter. The mixer uses two standard, double balanced mixer cells and a 90° hybrid coupler fabricated in a GaAs, metal semiconductor field effect transistor (MESFET) process. A low frequency quadrature hybrid produces a 100 MHz intermediate frequency (IF) output. This device is a smaller alternative to hybrid style image reject mixers and single sideband upconverter assemblies. The HMC521ALC4 eliminates the need for wire bonding, allowing use of surface-mount manufacturing techniques.