LMX25121065EVAL/NOPB National Semiconductor, LMX25121065EVAL/NOPB Datasheet - Page 24

• Manufacturer Part Number: LMX25121065EVAL/NOPB
• Description: EVALUATION BOARD FOR LMX25121065
• Manufacturer: National Semiconductor
• Series: PLLatinum™r

Specifications of LMX25121065EVAL/NOPB

• Main Purpose: Timing, Frequency Synthesizer
• Embedded: No
• Utilized Ic / Part: LMX2512
• Primary Attributes: Single Fractional-N and Integer-N PLL with VCO
• Secondary Attributes: 1.065GHz, CodeLoader Graphical User Interface
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: *LMX25121065EVAL; *LMX25121065EVAL/NOPB; LMX25121065EVAL

Special Note:
Version 2.1.3 of CodeLoader contains a known problem, to be corrected in the next version of
CodeLoader, associated with programming the RF PLL frequency.
To program the RF PLL to frequencies with fractional values greater than 0.5, the fractional
numerator must be entered manually. When the desired frequency is entered in the frequency
box, the program will round the fractional compensation up to the next integer N counter value.
The following example illustrates the problem.
Correct Values:
Desired Frequency:
Reference Frequency: 19.68 MHz
N Counter:
Fractional Comp.:
For the frequency 1072.72 MHz, the displayed values are:
Desired Frequency:
N Counter:
Fractional Comp.:
To overcome this problem, the N counter and fractional compensation need to be set manually.
In this example, set the N counter to 54 and the fractional compensation to 1000.
LMX2512LQ1065
1072.72 MHz
54.5081
1000
1082.4 MHz
55
0
LMX2512LQ1065 EVALUATION BOARD OPERATING INSTRUCTIONS
February 19, 2003
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