SP8861 Mitel Networks, SP8861 Datasheet - Page 6

• Manufacturer Part Number: SP8861
• Description: 13GHz Low Power Single-Chip Frequency Synthesiser
• Manufacturer: Mitel Networks

6
SP8861
24 bits whereas the reference byte will contain 18 bits. The
device requires 3 bytes, each with a chip select sequence,
totalling 66 bits to fully program.
required to set the counter is reduced by one bit, leaving an
PD2
An F1 or F2 update cycle will consist of a byte containing
When the dual modulus A counter is set to 48/9, the data
0
1
0
1
21
20
19
of external reference
Fig. 6b Connection
PD2
NC
0
0
1
1
LOOP FILTER
Fig. 6a Typical application
F
F
F
F
SL562
REFERENCE
REF
REF
REF
REF
EXTERNAL
C2
R2
CONTROLLED
OSCILLATOR
SOURCE
VOLTAGE
and F
and F
and F
and F
V
CC
2
C1
PD
PD
PD
PD
15V
outputs off, charge pumps 1 and 2 on
outputs on, charge pump 1 off, charge pump 2 on
outputs off, charge pump 1 disabled by lock detect, charge pump 2 on
outputs on, charge pump 1 disabled by lock detect, charge pump 2 on
Fig. 6c Use of lock detect circuit with PD1
Rx
Rx
0·1
AMPLIFIER
TO LOOP
15V
3
1n
1n
Ra > 23
2
SP8861
F
REF
1
Fig. 6 Application diagrams
V
PD2 current
28
CC
5
6
7
8
9
10
11
0·25
27
F
12
4
PD
26
13
3
Table 4
25
24
Cd
CONTROL
14
MICRO
2
SP8861
V
CC
15
1
unused bit in the 22-bit F1/F2 buffer. This bit must always be
set to zero when the 48/9 mode is required. Various
programming sequences are shown in Fig. 7.
up, making it possible to enter data when the device is in the
powered down state.
Result
Ra
Ra
28
16
The data entry and storage registers are always powered
15V
27
17
2·2k
26
18
CHARGE
FROM
PUMP
25
24
23
22
21
20
19
1n
Fig. 6d Simple discrete amplifier
FILTER
LOOP
Rb
15V
15V
RPD
33p
15V
470
22k
Rb >
39p
10k
PD2 current
0·25
VARICAP
SUPPLY
TO VCO