SP5669

Complete 2.7GHz single chip system
Compatible with UK DTT offset requirements
Optimised for low phase noise
Selectable divide by two prescaler
Selectable reference division ratio
Selectable reference/comparison frequency output
Selectable charge pump current
Four selectable I²C bus address
5level ADC
Pin compatible with the SP5658 3wire bus controlled synthesiser and SP5659 I²C bus synthesiser and SP5659 I²C bus synthesiser ESD protection;(Normal ESD handling procedures should be observed)

The SP5669 is a single chip frequency synthesiser designed for tuning systems up to 2.7GHz and offers step size compatible with DTT offset requirements.

The RF preamplifier SP5669 drives a divide by two prescaler which can be disabled for applications up to 2GHz, allowing direct interfacing with the programmable divider so enabling a step size equal to the comparison frequency. For applications up to 2.7GHz the divide by two is enabled, giving a step size of twice the comparison frequency.

The comparison frequency is obtained either from an onchip crystal controlled oscillator, or from an external source. The oscillator frequency F_ref or the comparison frequency F_comp may be switched to the REF/COMP output. This feature is ideally suited to providing the reference frequency for a second synthesiser such as in a double conversion tuner (see Fig. 8).

The synthesiser SP5669 is controlled via an I ² C bus, and responds to one of four programmable addresses which are selected by applying a specific voltage to the 'address' input. This feature enables two or more synthesisers to be used in a system.

The SP5669 contains four switching ports P0P3 and a 5level ADC. The output of the ADC can be read via the I ² C bus.

The SP5669 also contains a varactor line disable and chargepump disable facility.