SP5848 Datasheet, PDF (4/9 Pages) Mitel Networks Corporation – 2.2/1.3GHz 3-Wire Bus Dual Low Phase Noise PLL

SP5848
Absolute maximum Ratings
All voltages referred to Vee at 0V
Characteristic
Supply voltages
RF1 input voltage
RF2 input voltage
All I/O ports DC offset
Storage temperature
Junction temperature
Package thermal resistance
chip to ambient
chip to case
Power consumption with all
Vcc =5.5V
ESD protection
Preliminary Information
Value
Conditions
Min
Max Units
-0.3
7
V
2.5 Vp-p Differential
2.5 Vp-p Differential
-0.3 Vcc+0.3 V
-55
+125
°C
150
°C
100 °C/W
30 °C/W
121 mW All ports off
2
kV Mil std 883 latest revision methood 3015
class 1
Functional Description
The SP5848 contains two PLL frequency synthesiser
loops, each independently programmable from a 3-wire
bus. The device is optimised for application in double
conversion tuners where synthesiser 1 would form part
of the upconverter and synthesiser 2 part of the down
converter. Both loops are optimised for application in low
phase noise loops and furtherly synthesiser 2 offers low
comparison frequencies. A block diagram is contained in
Figure 1.
The device is programmed via a 3-wire bus where data
is fed on serial data and clock lines and is gated by an
enable line. Figure 3 indicates the format of the data.
The sequence and timing of data load is described below
in ‘programming mode’ description. Each synthesiser is
independently addressable and is defined by the LSB bit
within the data transmission.
A common reference frequency source and reference
divider is used to derive the comparison frequency for
both PLL loops. The reference division ratio is
programmable via the data bus as defined in Tables1
and 2.
The charge pump current for each loop is also
programmable via the data bus as defined in Tables 3
and 4
Two switching ports are provided to control switching
functions within the tuner. These ports also access test
signals within the PLL as defined in Figure 7. Ports
power up in high impedance state.
4
Programming Mode
The SP5848 is designed to be programmed from a
standard 3-wire bus consisting of clock, data and enable,
where the serial clock and data lines can be shared with
other devices and the enable line is a unique line for
individual device selection. To simplify programming
each synthesiser is independently addressed, with the
required loop being selected by the LSB bit , which
functions as the address, therefore to fully program the
device two complete data transmissions must be sent.
The data format for each transmission is contained in
Figure 3.
Test modes as described in Figure 7, can be invoked by
setting bit T0 in synthesiser 2 data word to a ‘1’ and
sending control data for bits T1-T2. In normal operation
where T0 is set to a ‘0’ bits T1 and T2 do not need to be
transmitted