Preliminary Information
SP5848
SP5848
2.2/1.3GHz 3-Wire Bus Dual Low Phase Noise PLL
Preliminary Information
DS5076
Issue 1.6
October 1999
Features
G
Ordering Information
SP5848/KG/QP1S
SP5848/KG/QP1T
G
G
G
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)
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.
G
G
G
G
Applications
G
TV, VCR, and cable tuning systems
PUMP 1
11 BIT
COUNT
RF1 INPUT
16/17
4 BIT
COUNT
DRIVE 1
15 BIT LATCH
2 BIT
LATCH
DATA
CLOCK
ENABLE
DATA
INTERFACE
5 BIT
LATCH
2
9
DIVIDE
2 BIT
LATCH
PORT P0
PORT P1
16 BIT LATCH
1 BIT
LATCH
PUMP 2
12 BIT
COUNT
RF 2 INPUT
16/17
4 BIT
COUNT
DRIVE 2
Figure 1 Block Diagram
1