CX74061

www.DataSheet4U.com PRODUCT SUMMARY CX74061: Rx ASIC for CDMA, AMPS, PCS, and GPS Mobile Handset Applications APPLICATIONS Tri-band, quad-mode handsets PCS and GPS phones CDMA and GPS phones After RF LNA signal amplification and filtering from the antenna, the received signal is mixed down from RF to the IF. There are separate mixers for AMPS, CDMA-cellular, CDMAPCS, and GPS modes. The CDMA and PCS mixers have balanced outputs for the IF SAW filters, while the AMPS differential output can be combined externally to mate to a single-ended SAW filter. The GPS mixers have a differential output for an external L-C bandpass filter. After IF filtering, the IF signal is amplified by a Variable Gain Amplifier (VGA) and fed to an I/Q demodulator, resulting in baseband I/Q signals at the output. The CX74061 is also designed with two Local Oscillator (LO) input ports, one for the AMPS/CDMA/PCS mixer and one for the GPS mixer. These mixers operate at different RF frequency inputs, but have the same IF frequency output. This usually refers to a single IF (SIF) plan at 183.6 MHz. The PCS/CELL_LO signal (pin 36) provides an LO port for the CDMA-cellular and CDMA-PCS mixers. The PCS band is selected by default as an input LO frequency to the PCS mixer. In the cellular band, the frequency is divided by two by an internal divider, which provides the LO input to the cellular mixer. Only one external VCO is required for the UHF PLL. Additionally, the mixer LO signal is coupled and amplifi...