Description

The SP5848 is a dual PLL frequency synthesizer controlled by a 3-wire bus optimised for application in double conversion tuners.

Each synthesiser loop within the SP5848 is independently addressable and contains an RF programmable divider, phase/frequency detector and charge pump/loop amplifier section; a common reference frequency oscillator and divider chain is provided, whose ratios for each loop are independently programmable.

Both synthesisers are optimised for low phase noise performance and in addition synthesiser 2 is capable of operation with a low comparison frequency.

Features

? Dual independent PLL frequency synthesisers in a single package, optimised for double conversion cable tuners, offering improved application

? 2.2GHz up-synthesiser optimised for low phase noise up to comparison frequencies of 4MHz

? 1.3GHz down-synthesiser optimised for low phase noise AND small step size

? Common reference oscillator and divider with independently selectable ratios for each synthesiser

? 10:1 programmable charge pump current ratio in up synthesiser

? 3-Wire bus programmable, each synthesiser indepently addressable

? Low power consumption, typ 100mW at 5V

? ESD protection, (Normal ESD handling procedures should be observed)

Applications

? TV, VCR, and cable tuning systems