lmx2377u National Semiconductor Corporation, lmx2377u Datasheet - Page 11

• Manufacturer Part Number: lmx2377u
• Description: Lmx2377u Pllatinum? Ultra Low Power Dual Frequency Synthesizer For Rf Personal Communications 2.5 Ghz/1.2 Ghz
• Manufacturer: National Semiconductor Corporation

PHASE NOISE CHARACTERISTICS
L
L(f) Main
L
L(f) Aux
N
N
Electrical Characteristics
V
Note 4: Some of the values in this range are illegal divide ratios (B
≥ P
Note 5: Refer to the LMX2377U f
Note 6: Refer to the LMX2377U Charge Pump Test Setup section
Note 7: Refer to the Charge Pump Current Specification Definitions for details on how these measurements are made.
Note 8: Refer to the LMX2377U OSC
Note 9: Refer to the LMX2377U Serial Data Input Timing section
Note 10: Normalized Phase Noise Contribution is defined as : L
measured at an offset frequency, f, in a 1 Hz bandwidth. The offset frequency, f, must be chosen sufficiently smaller than the PLL’s loop bandwidth, yet large enough
to avoid substantial phase noise contribution from the reference source. N is the value selected for the feedback divider and F
comparison frequency..
Note 11: The synthesizer phase noise is measured with the LMX2370TMEB/LMX2370SLBEB/LMX2370SLEEB Evaluation boards and the HP8566B Spectrum
Analyzer.
(f) Main
(f) Aux
Symbol
CC
*
(P−1), where P is the value of the prescaler selected.
= V
P
Main = V
Main Synthesizer Normalized Phase
Noise Contribution
(Note 10)
Main Synthesizer Single Side Band
Phase Noise Measured
Aux Synthesizer Normalized Phase
Noise Contribution
(Note 10)
Aux Synthesizer Single Side Band
Phase Noise Measured
P
Aux = Vµc = 3.0V, −40˚C ≤ T
IN
Parameter
Sensitivity Test Setup section
in
Sensitivity Test Setup section
(Continued)
N
A
(f) = L(f) − 20 log (N) − 10 log (F
<
≤ +85˚C, unless otherwise specified
A). To obtain continuous legal division, the Minimum Divide Ratio must be calculated. Use N
TCXO Reference Source
ID
f
f = 1 kHz Offset
F
Loop Bandwidth = 7.5 kHz
N = 12250
F
V
ID
PWDN Aux Bit = 1
T
(Note 11)
TCXO Reference Source
ID
f
f = 1 kHz Offset
F
Loop Bandwidth = 12 kHz
N = 4500
F
V
ID
PWDN Main Bit = 1
T
(Note 11)
IN
IN
φMain
OSC
A
φAux
OSC
A
OSC
OSC
o
o
o
o
Main = 2450 MHz
Aux = 900 MHz
= 25˚C
= 25˚C
Main Bit = 1
Main Bit = 1
Aux Bit = 1
Aux Bit = 1
= 10 MHz
= 10 MHz
= 200 kHz
= 0.632 V
= 0.632 V
= 200 kHz
11
Conditions
PP
PP
φ
), where L(f) is defined as the single side band phase noise
Min
φ
is the Main/Aux phase detector
-212.0
-77.24
-212.0
-85.94
Value
Typ
www.national.com
Max
Units
dBc/
dBc/
dBc/
dBc/
Hz
Hz
Hz
Hz