LMX2430EVAL National Semiconductor, LMX2430EVAL Datasheet - Page 6

• Manufacturer Part Number: LMX2430EVAL
• Description: EVALUATION BOARD FOR LMX2430
• Manufacturer: National Semiconductor
• Series: PLLatinum™r

Specifications of LMX2430EVAL

• Main Purpose: Timing, Frequency Synthesizer
• Utilized Ic / Part: LMX2430
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Secondary Attributes: -
• Embedded: -
• Primary Attributes: -
• Lead Free Status / Rohs Status: Not Compliant
• Other names: *LMX2430EVAL

LMX2430SLE EVALUATION BOARD OPERATING INSTRUCTIONS
2.3
Reference Spur Measurement Using A Spectrum Analyzer
The reference sidebands can be seen on a spectrum analyzer and are measured in dBc. The
CodeLoader software is used to set the desired frequency and to program the LMX2430SLE
device. Refer to Appendix E for more details. The spectrum analyzer is set to the desired center
frequency and the span is set to allow the reference sidebands to be viewed. For the
LMX2430SLE device, the span can be set to 3 MHz during the RF VCO measurement because
its loop filter design is based on a 1 MHz reference frequency. The span can be set to 500 kHz
during the IF VCO measurement because its loop filter is based on a 200 kHz reference
frequency. The spurious output is the difference between the level of the VCO output frequency
tone and the level of the spur at an offset equal to the carrier frequency +/- the reference
frequency. For a more accurate account of the device’s spurious performance, the reference
spurs across the VCO’s frequency band should be determined. The worst-case spur is typically
defined as the PLL’s spur performance.
4
LMX2430SLEFPEB
February 3,2006