SKY77521 is a transmit and receive Front End Module (FEM) designed in a very low profile (1 mm), compact form factor for quad-band cellular handsets comprising GSM850/900, DCS1800, and PCS1900 operation — a complete transmit VCO-to-Antenna and Antenna-toreceive SAW filter solution. The FEM also supports Class 12 General Packet Radio Service (GPRS) multi-slot operation and EDGE Polar Modulation. WCDMA switch-through support is provided by three dedicated high-linearity ports. Please note: SKY77521 is being discontinued and is not recommended for new design. The suggested replacement is SKY77544 .