AD9510 Analog Devices, AD9510 Datasheet - Page 22

• Manufacturer Part Number: AD9510
• Manufacturer: Analog Devices

AD9510
Table 15. Frequency Limits per Prescaler Mode
Mode (DM = Dual Modulus)
P = 2 DM (2/3)
P = 4 DM (4/5)
P = 8 DM (8/9)
P = 16 DM
P = 32 DM
A AND B COUNTERS
The AD9510 B Counter has a bypass mode (B = 1) that is not
available on the ADF4106. The B counter bypass mode is only
valid when using the prescaler in a FD mode. The B counter is
bypassed by writing 1 to the B counter bypass bit in the register
map. Note that the A counter is not used when prescaler is in
FD mode.
Note also that the A/B Counters have their own reset bit that is
primarily intended for test. A and B counters can also be reset
using the shared R, A, and B counters reset bit.
Table 16. P, A, B, R − Smallest Values for N
F
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
REF
R
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
P
1
2
1
1
1
2
2
2
2
2
2
2
2
2
2
4
4
A
X
X
X
X
X
X
0
1
2
1
X
0
1
X
0
0
1
B
1
1
3
4
5
3
3
3
3
4
5
5
5
6
6
3
3
CLK2
< 500 MHz
< 750 MHz
< 1.5 GHz
< 1.5 GHz
< 1.5 GHz
N
1
2
3
4
5
6
6
7
8
9
10
10
11
12
12
12
13
F
10
20
30
40
50
60
60
70
80
90
100
100
110
120
120
120
130
Rev. PrA | Page 22 of 41
VCO
Mode
FD
FD
FD
FD
FD
FD
DM
DM
DM
DM
FD
DM
DM
FD
DM
DM
DM
SETTING VALUES FOR P, A, B, AND R
When operating the AD9510 in a dual-modulus mode, the
input reference frequency, F
frequency, F
When operating the prescaler in a fixed divide mode the A
counter is not used and the equation simplifies to
By using combinations of dual modulus and fixed divide modes,
the AD9510 can achieve values of N all the way down to N = 1.
Table 16 shows how a 10 MHz reference input may be locked to
any integer multiple of N. Note that the same value of N may be
derived in different ways, as illustrated by the case of N = 12.
F
F
VCO
VCO
= (F
= (F
VCO.
REF
REF
/R) × (PB + A) = F
/R) × (PB) = F
Notes
P = 1, B = 1 (Bypassed)
P = 2, B = 1 (Bypassed)
P = 1, B = 3
P = 1, B = 4
P = 1, B = 5
P = 2, B = 3
P/P + 1 = 2/3, A = 0, B = 3
P/P + 1 = 2/3, A = 1, B = 3
P/P + 1 = 2/3, A = 2, B = 3
P/P + 1 = 2/3, A = 1, B = 4
P = 2, B = 5
P/P + 1 = 2/3, A = 0, B = 5
P/P + 1 = 2/3, A = 1, B = 5
P = 2, B = 6
P/P + 1 = 2/3, A = 0, B = 6
P/P + 1 = 4/5, A = 0, B = 3
P/P + 1 = 4/5, A = 1, B = 3
Preliminary Technical Data
REF
, is related to the VCO output
REF
× N/R
REF
× N/R