ACD2202
For the up converter, the 4 MHz crystal oscillator frequency and the 250 KHz phase detector comparison
frequency are used to yield RPLL1 = 4 MHz / 250 KHz = 16, and so the bit values for the up converter R counter
are RPLL1 = 000000000010000.
Calculation of Main Divider Values
The values for the A and B counters are determined by the desired VCO output frequency for the local
oscillator and the phase detector comparison frequency:
N = fVCO / f PD
B = trunc(N / P)
A = N - (B x P)
The down converter local oscillator frequency will be 1087.75 MHz - 45.75 MHz = 1042 MHz in this example.
The main divider ratio for the down converter, then, is NPLL2 = 1042 MHz / 62.5 KHz = 16672. Since P = 64 in the
ACD2202, BPLL2 = trunc(16672 / 64) = 260, and APLL2 = 16672 - (260 x 64) = 32. These results give bit values
of BPLL2 = 00100000100 and APLL2 = 0100000 for the B and A counters.
The up converter local oscillator frequency will be 499.25 MHz + 1087.75 MHz = 1587 MHz in this example.
Therefore, NPLL1 = 1587 MHz / 250 KHz = 6348, BPLL1 = trunc(6348 / 64) = 99, and APLL1 = 6348 - (99 x 64) = 12.
These results give bit values of BPLL1 = 00001100011 and APLL1 = 0001100 for the B and A counters.
Phase Detector Polarity
Assuming the VCO for the up converter has a negative slope, the phase detector polarity for PLL1 should be
negative, and D1PLL1 = 1. If the VCO for the down converter has a positive slope, the phase detector polarity for
PLL2 should be positive, and D1PLL2 = 0.
In summary, for this example, the four register programming words are shown in Tables 16 and 17:
Table 16: PLL1 and PLL2 Reference Divider Register Bits
for Synthesizer Programming Example
MSB
LSB
22 21 20 19 18 17 16 15 14 13 12 11 10
9
8
7
6
5
4
3
2
1
Program Mode Reference Divider R Counter
Select
D
5
D
4
D
3
D
2
D
1
R
R
R
R
R
R
R
9
R
8
R
7
R
6
R
5
R
4
R
3
R
2
R
1
S
2
S
1
15 14 13 12 11 10
0
0
0
0
0
0
0
0
1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
1
0
0
0
0
1
0
0
0
0
0
0
0
0
0
1
0
0
Table 17: PLL1 and PLL2 Main Divider Register Bits
for Synthesizer Programming Example
MSB
LSB
22
21 20 19 18 17 16 15 14 13 12 11 10
9
8
7
6
5
4
3
2
1
Program
Mode
Main Divider B Counter
Main Divider A Counter
Select
C
2
C
1
B
B
B
9
B
8
B
7
B
6
B
5
B
4
B
3
B
2
B
1
A
7
A
6
A
5
A
4
A
3
A
2
A
1
S
2
S
1
11 10
0
0
0
0
0
0
0
0
1
0
0
0
0
1
0
1
0
0
0
0
1
0
0
1
0
1
0
0
1
0
0
0
0
1
0
1
0
0
0
0
0
1
1
1
Data Sheet - Rev 2.1
12/2003
14
ANADIGICS [ ANADIGICS, INC ]
