The SP5668 is a single chip frequency synthesiser designed for tuning systems up to 2.7GHz.
The RF preamplifer contains a divide by two prescaler which can be disabled for applications up to 2GHz so enabling a step size equal to the comparison frequency up to 2GHz and twice the comparison frequency up to 2.7GHz.
Comparison frequencies are obtained either from a crystal controlled on–chip oscillator or from an external source.
The device contains three switching ports, P0 – P2, together with an ’in–lock’ flag output. Various test modes including varactor disable and charge pump disable are also included.

FEATURES
■ Complete 2.7GHz single chip system
■ Optimised for low phase noise
■ Selectable divide by two prescaler
■ Selectable reference division ratio
■ Charge pump disable
■ Varactor line disable
■ ‘In–lock’ flag
■ Two selectable charge pump currents
■ Three switching ports
■ Reference frequency output
■ ESD protection (Normal ESD handling procedures should be observed)

APPLICATIONS
■ SAT, TV, VCR and Cable tuning systems
■ Communications systems