LMX1600EVAL National Semiconductor, LMX1600EVAL Datasheet - Page 10

• Manufacturer Part Number: LMX1600EVAL
• Manufacturer: National Semiconductor

Specifications of LMX1600EVAL

• Lead Free Status / Rohs Status: Not Compliant

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2.0 Programming Description
2.3.6 Programmable Counter Divide Ratio (Main B COUNTER)
Note 13: Divide ratio: 3 to 2,047 (Divide ratios less than 3 are prohibited)
Note 14: Divide ratio: 3 to 4,095 (Divide ratios less than 3 are prohibited)
2.3.7 Pulse Swallow Function
The N divider counts such that it divides the VCO RF frequency by (P+1) for A times, and then divides by P for (B – A ) times.
The B value (B_CNTR) must be ≥ 3. The continuous divider range for the Main PLL N divider is from 992 to 65,535 for 2 GHz
option, from 240 to 65,535 for 1.1 GHz option, and from 56 to 32,767 for 500 MHz option. Divider ratios less than the minimum
value are achievable as long as the binary counter value is greater than or equal to the swallow counter value (B_CNTR ≥
A_CNTR).
f
N = (P x B) + A
VCO
f
f
R:
N:
B:
A:
P:
VCO
OSC
= N x ( f
: Output frequency of external voltage controlled oscillator (VCO)
: Output frequency of the external reference frequency oscillator (input to OSC
MAIN_B_CNTR ≥ MAIN_A_CNTR.
See section 2.3.7 for calculation of VCO output frequency.
MAIN_B_CNTR ≥ MAIN_A_CNTR.
See section 2.3.7 for calculation of VCO output frequency.
Preset divide ratio of binary programmable reference counter (R_CNTR)
Preset divide ratio of main programmable integer N counter (N_CNTR)
Preset divide ratio of binary programmable B counter (B_CNTR)
Preset value of binary 4-bit swallow A counter (A _CNTR)
Preset modulus of dual modulus prescaler (P = 32 for 2 GHz option, P=16 for 1.1 GHz option, and P=8 for 500 MHz
option)
OSC
/ R )
Divide Ratio
Divide Ratio
4,095
3
4
•
2,047
3
4
•
11
0
0
1
•
10
0
0
1
•
10
0
0
1
•
9
0
0
1
•
9
0
0
1
•
1.1 GHz option (12 bit)
(Continued)
2 GHz option (11 bit)
8
0
0
1
•
MAIN_B_CNTR
MAIN_B_CNTR
8
0
0
1
•
7
0
0
1
•
7
0
0
1
•
10
6
0
0
1
•
6
0
0
1
•
5
0
0
1
•
5
0
0
1
•
4
0
0
1
•
4
0
0
1
•
3
0
0
1
•
3
0
0
1
•
IN
).
2
0
1
1
•
2
0
1
1
•
1
1
0
1
•
1
1
0
1
•
0
1
0
1
•
0
1
0
1
•