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
Ordering Information
SP5848/KG/QP1S
•
Dual independent PLL frequency synthesisers in a
single package, optimised for double conversion
cable tuners, offering improved application
SP5848/KG/QP1T
•
•
•
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
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.
indepently addressable
•
•
Low power consumption, typ 100mW at 5V
ESD protection, (Normal ESD handling
procedures should be observed)
Both synthesisers are optimised for low phase noise
performance and in addition synthesiser 2 is capable of
operation with a low comparison frequency.
Applications
•
TV, VCR, and cable tuning systems
PUMP 1
DRIVE 1
11 BIT
COUNT
RF1 INPUT
16/17
4 BIT
COUNT
PORT P0
15 BIT LATCH
2 BIT
LATCH
2 BIT
LATCH
PORT P1
DATA
DATA
INTERFACE
CLOCK
5 BIT
LATCH
29
DIVIDE
ENABLE
1 BIT
LATCH
16 BIT LATCH
PUMP 2
DRIVE 2
12 BIT
COUNT
16/17
4 BIT
RF 2 INPUT
COUNT
Figure 1 - Block Diagram
1
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