Alpha Industries introduces low-capacitance varactors for VCO designs in IMT-2000 (WCDMA/UMTS) applications. The three recommended silicon varactor diodes for WCDMA/UMTS are SMV1232-079, SMV1263-079, and SMV1405-079. These varactors have low series resistance for low phase noise and low capacitance, making them suitable for applications up to 2.5 GHz. Manufactured in the ultra-small SC-79 package for reduced package parasitics, the devices are available in tape and reel for high-volume applications.