GPS receiver down converter circuit based on RF2498

The RF2498 is a high performance CDMA tri-band/dual mode integrated LNA/mixer circuit, a tri-band LNA/downconverter. The RF2498 can be used in CDMA/cellular/PCS/GPS handsets, JCDMA/GSP handsets, CDMA modems/data cards, commercial and consumer systems, and battery-powered portable devices. The RF2498 meets IS-98 sensitivity, intermodulation, and single tone requirements. The RF2498 has a gain control of 29dB in the PCS band and 27.5dB in the cellular band. The RF2498 provides 37dB of gain for a GPS LNA/mixer application. The RF2498 uses a 3-state gain control method to meet IS-98 IMD testing. The RF2498 has a divide-by-2 pre-divider that allows the use of single-sideband or double-sideband VCOs. There is an integrated TX LO buffer on the chip. The bias current for the mixer and LNA blocks can be set by resistors off the chip. The chip adopts LCC (1eadless chip cartier)-32 package, and the chip size is 51MM×51MM