SKY74963-23

• Direct down-conversion receiver eliminates the image reject/IF filters
• Three separate LNAs with single-ended inputs
• Integrated PAC loop
• 26 MHz integrated crystal oscillator with 26 MHz output
• Low external component count

RF Transceiver w/Power Ramping Controller and Integrated Cryst Osc for Multi-Band GSM/GPRS/EDGE Apps

The SKY74963-23 RF transceiver is a highly integrated device formulti-band Global System for Mobile Communications (GSM) orGeneral Packet Radio Service (GPRS) applications. The SKY74963-23 requires a minimal number of external components to complete aGSM radio subsystem. The SKY74963 supports GSM850,EGSM900, DCS1800, and PCS1900 applications. The receiveralso supports Enhanced Data for GSM Evolution (EDGE) downlinkapplications.

The receive path of SKY74963-23 implements a direct down-conversionarchitecture that eliminates the need for Intermediate Frequency(IF) components. The SKY74963-23 consists of three integrated LowNoise Amplifiers (LNAs), a quadrature demodulator, tunablereceiver baseband filters, and a DC Offset Correction (DCOC)sequencer.

In the transmit path, the SKY74963-23 consists of an In-phase andQuadrature (I/Q) modulator within a frequency translation loopdesigned to perform frequency up-conversion with high outputspectral purity. This loop also contains a phase-frequencydetector, charge pump, mixer, programmable dividers, and highpower transmit Voltage Controlled Oscillators (VCOs) with noexternal tank required. With the integrated gain controller (and anintegrator ), the SKY74963-23 realizes the Power Amplifier Control (PAC)functionality when combined with a coupler, a Radio Frequency(RF) detector, and a Power Amplifier (PA).

The SKY74963-23 also features an integrated, fully programmable,sigma-delta fractional-N synthesizer suitable for GPRS multi-slotoperation. Except for the loop filter, the frequency synthesizerfunction, including a wideband VCO, is completely on-chip. Thereference frequency for the synthesizer SKY74963-23 is supplied by theintegrated crystal oscillator circuitry.