SKY74067

• Low power consumption in all operating modes
• Direct upconversion architecture
• Device controlled using a three-wire read/write serial bus interface with independent supply voltage
• Baseband RC filter to reject receive band noise
• Fully integrated VCO with auto-tuning
• Dual-mode fractional-N/integer-N PLL
• Variable gain PA drivers
• Differential cellular driver output matched to 200
• Single-ended PCS driver output matched to 50
• Transmit power control with >75 dB dynamic range
• Low current consumption at low transmit power minimizes current consumption and noise
• Hardware TX_ENABLE for gated mode operation
• RFLGA? (32-pin, 5 x 5 x 1 mm) Pb-free (MSL3, 260 °C per JEDEC J-STD-020) package with downset paddle

Dual-Band CDMA2000 Transmitter for Cellular CDMA and PCS Femtocell Applications

The SKY74067 transmitter is a highly integrated device for dualbandCode Division Multiple Access (CDMA) femtocell basestation applications. The SKY74067 supports femtocells in thecellular CDMA and Personal Communications System (PCS)bands.

The SKY74067 requires a minimum number of external componentsto complete a CDMA2000 radio subsystem. Included on-chip arethe baseband filter, direct upconversion In-Phase and Quadrature(I/Q) mixers, variable gain power amplifier (PA) drivers, a fullyintegrated Voltage Controlled Oscillator (VCO) with Local Oscillator(LO) generation blocks, and a dual-mode fractional-N/integer-NPhase Locked Loop (PLL).

External components needed for operation include bias resistors,bypass capacitors, and passives to comprise the PLL loop filter.

The signal of SKY74067 enters the chip as an analog baseband In-Phase andQuadrature (I/Q) signal. It is filtered by the baseband filter andupconverted to the desired RF transmit frequency. The signal isamplified by one of two upconverters, depending on whether thechip is operating in cellular or PCS mode. The resulting signal isfed through the appropriate PA driver stage to provide variableoutput power and to drive the external PA. The signal of SKY74067 is thenfiltered by an external Surface Acoustic Wave (SAW) filter andsent to the PA to obtain the final rated power.