SA8027

INTEGRATED CIRCUITS SA8027 2.5 GHz low voltage, low power RF fractional-N/IF integer frequency synthesizer Product data Supersedes data of 2001 Jul 18 2001 Aug 21 Philips Semiconductors Philips Semiconductors Product data 2.5 GHz low voltage, low power RF fractional-N/IF integer frequency synthesizer SA8027 GENERAL DESCRIPTION The SA8027 BICMOS device integrates programmable dividers, charge pumps and phase comparators to implement phase-locked loops. The device is designed to operate from 3 NiCd cells, in pocket phones, with low current and nominal 3 V supplies. The synthesizer operates at VCO input frequencies up to 2.5 GHz. The synthesizer has fully programmable main, auxiliary and reference dividers. All divider ratios are supplied via a 3-wire serial programming bus. The main divider is a fractional-N divider with programmable integer ratios from 512 to 65535. Separate power and ground pins are provided to the charge pumps and digital circuits. The ground pins should be externally connected to prevent large currents from flowing across the die and causing damage. VDDCP must be equal to or greater than VDD. The charge pump current (gain) is fully programmable, while ISET is set by an external resistance at the RSET pin (refer to section 1.5, Main Output Charge Pumps and Fractional Compensation Currents). The phase/frequency detector charge pump outputs allow for implementing a passive loop filter. LOCK TEST VDD GND RFin+ RFin– GNDCP PHP PHI 1 2 3 4 5 6 7 8 9 20 PO...