sp5668 ETC-unknow, sp5668 Datasheet - Page 5

• Manufacturer Part Number: sp5668
• Description: 2.7ghz 3-wire Controlled Synthesiser
• Manufacturer: ETC-unknow

Phase Noise
performance even when operated with a standard low profile
4MHz crystal and a high comparison frequency, e.g. 2MHz.
standard application is contained in Table 4. It has been
demonstrated that even higher levels of performance will be
achieved in a tuner application.
X = Don't care
The SP5668 has been designed to offer good phase noise
The typical phase noise performance measured in the
R2
P1
0
0
0
0
1
1
1
1
X
0
0
1
1
ENABLE
R2
CO
OS
T0
PE
P2, P1, P0
2
CLOCK
16
DATA
,
to 2
R1
,
0
R1
P0
0
0
1
1
0
0
1
1
X
0
1
0
1
R0
MSB
t : Programmable divider ratio control bits
t : Reference divider ratio control bits (see Table 1)
t : Port control bits
t : Charge Pump current select (see Table 3)
t : Drive output disable switch
t : Test mode enable (see Table 2)
: 2 Prescaler (Enable = 1, Disable = 0)
P2 P1 P0 TO OS CO R2
2
26
R0
T0
0
1
0
1
0
1
0
1
0
1
1
1
1
2
Figure 3 - Data format and timing
Table 1 - Reference division ratio
25
2
24
Table 2 - Test modes
2
23
2
RATIO
22
FUNCTIONAL DESCRIPTION
Normal operation
Charge pump sink. LOCK output = Lo Z
Charge pump source. LOCK output = Hi Z
Charge pump disable. LOCK output = Lo Z
Port P1 = Fcomp: Port 0 = Fpd/2
128
256
16
32
64
2
4
8
2
21
Test Modes
the comparison frequency Fcomp, can be switched to ports P0
and P1 respectively.
current, and may be disabled to high impedance state.
within the data word, so switching the external transistor 'OFF'
and allowing an external voltage to be written to the varactor
line for tuner alignment purposes.
2
The programmable divider output divided by two Fpd/2 and
The charge pump can be forced to either source or sink
The varactor DRIVE output can be disabled by the OS bit
The test modes are described in Table 2.
20
2
R1 R0 PE
19
2
Comparison Frequency with a 4MHz
18
2
17
2
FREQUENCY DATA
16
external reference
15.625kHz
31.25kHz
62.5kHz
500kHz
250kHz
125kHz
2MHz
1MHz
2
0
LSB
SP5668
5