SP5669
2.7GHz I2C Bus Controlled Synthesiser
Preliminary Information
DS4852 -
Issue 2.1
May 1999
Features
Ordering Information
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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
SP5669/KG/MP1S (Tubes)
SP5669/KG/MP1T (Tape and reel)
Four selectable I2C bus address
5–level ADC
Pin compatible with the SP5658 3–wire bus
controlled synthesiser and SP5659 I2C bus
synthesiser and SP5659 I2C bus synthesiser
ESD protection; (Normal ESD handling
procedures should be observed)
The comparison frequency is obtained either from an
on–chip crystal controlled oscillator, or from an external
source. The oscillator frequency Fref or the comparison
frequency Fcomp may be switched to the REF/COMP
output. This feature is ideally suited to providing the
referencefrequencyforasecondsynthesisersuchasin
a double conversion tuner (see Fig. 8).
The synthesiser is controlled via an I 2 C bus, and
respondstooneoffourprogrammableaddresseswhich
are selected by applying a specific voltage to the
‘address’ input. This feature enables two or more
synthesisers to be used in a system.
Applications
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Complete 2.7GHz single chip system
Optimised for low phase noise
The device contains four switching ports P0–P3 and a
Description
5–level ADC. The output of the ADC can be read via the
I 2 C
bus.
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 device also contains a varactor line disable and
chargepump disable facility.
The RF preamplifier 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.