LMX2485E EVAL National Semiconductor, LMX2485E EVAL Datasheet - Page 9

• Manufacturer Part Number: LMX2485E EVAL
• Description: BOARD EVALUATION LMX2485E
• Manufacturer: National Semiconductor
• Series: PLLatinum™r

Specifications of LMX2485E EVAL

• Main Purpose: Timing, Frequency Synthesizer
• Utilized Ic / Part: LMX2485E
• Lead Free Status / RoHS Status: Not applicable / Not applicable
• Secondary Attributes: -
• Embedded: -
• Primary Attributes: -

RF PLL Fractional Spurs with different Delta Sigma Modulator Order
L M X 2 4 8 5 E
E V A L U A T I O N
9
FM = 2 (2
(FM =2 is the recommended setting)
Fractional Spurs measured at 49.2 MHz
CP gain set to 0.76 mA (8X)
Fraction Compensation set to 1/5
Dithering disabled.
In these three plots, you will note that 200 kHz
Fractional Spurs only varies slightly. The
harmonics (400 kHz and 600 kHz) spurs increase
as the delta sigma modulator order increases.
FM=3 (3
Fractional Spurs measured at 49.2 MHz
CP gain set to 0.76 mA (8X)
Fraction Compensation set to 1/5
Dithering disabled.
FM=0 (4
Fractional Spurs measured at 49.2 MHz
CP gain set to 0.76 mA (8X)
Fraction Compensation set to 1/5
Dithering disabled.
B O A R D
rd
th
nd
order delta sigma modulator)
order delta sigma modulator)
order delta sigma modulator)
O P E R A T I N G
I N S T R U C T I O N S