LMX2314 National Semiconductor Corporation, LMX2314 Datasheet - Page 17

• Manufacturer Part Number: LMX2314
• Description: 1.2 Ghz Frequency Synthesizer For Rf Personal Communications
• Manufacturer: National Semiconductor Corporation

Application Information
MEASUREMENT RESULTS
The reference spurious level is
filter attenuation and the low spurious noise level of the
LMX2315
The phase noise level at 10 kHz offset is
FIGURE 6 PLL Phase Noise 10 kHz Offset
FIGURE 5 PLL Reference Spurs
k
b
74 dBc due to the loop
(Continued)
b
80 dBc Hz
TL W 11766 – 21
TL W 11766 – 23
17
ure 8 shows the switching waveforms for a frequency jump
The phase noise level at 1 kHz offset is
Of concern in any PLL loop filter design is the time it takes
to lock in to a new frequency when switching channels Fig-
of 865 MHz to 915 MHz By narrowing the frequency span
of the HP53310A Modulation Domain Analyzer enables
evaluation of the frequency lock time to within
The lock time is seen to be less than 500 ms for a frequency
jump of 50 MHz
FIGURE 7 PLL Phase Noise
FIGURE 8 Frequency Jump Lock Time
1 kHz Offset
b
79 5 dBc Hz
TL W 11766 – 22
TL W 11766 – 24
g
500 Hz