LMX2471 National Semiconductor, LMX2471 Datasheet - Page 5

• Manufacturer Part Number: LMX2471
• Description: 3.6 GHz Delta-Sigma Fractional-N PLL with 1.7 GHz Integer-N PLL
• Manufacturer: National Semiconductor

DIGITAL INTERFACE (DATA, CLK, LE, EN, ENRF, Ftest/LD, FLoutRF, FLoutIF)
V
MICROWIRE INTERFACE TIMING
T
T
T
T
T
T
PHASE NOISE
L
L
Electrical Characteristics
CS
CH
CWH
CWL
ES
EW
F1Hz
F1Hz
Note 3: 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 loop bandwidth, yet large enough
to avoid substantial phase noise contribution from the reference source. The offset chosen was 4 KHz.
MICROWIRE INPUT TIMING DIAGRAM
Note 4: Note that although it is valid return the CLK, DATA, and LE pins to a high state after programming is complete, this is not the preferred method. One problem
with keeping these pins at a high voltage is that there is increased leakage through these pins if they are not grounded. Also, the action of returning the CLK pin to
a high voltage after programming is finished can create an extra clock cycle that can cause problems if it is done too soon after the LE pin voltage is returned to a
high state. If possible, it is best to return all microwire pins to 0 V when the PLL is not being programmed in order to avoid these issues with leakage and timing.
OL
Symbol
RF
IF
Low-Level Output Voltage
Data to Clock Set Up Time
Data to Clock Hold Time
Clock Pulse Width High
Clock Pulse Width Low
Clock to Load Enable Set
Up Time
Load Enable Pulse Width
RF Synthesizer Normalized
Phase Noise Contribution
(Note 3)
IF Synthesizer Normalized
Phase Noise Contribution
(Note 3)
Parameter
(V
CC
= 2.5V; -40˚C ≤ T
I
See Microwire Input Timing
See Microwire Input Timing
See Microwire Input Timing
See Microwire Input Timing
See Microwire Input Timing
See Microwire Input Timing
RF_CPG = 0
RF_CPG = 3
RF_CPG = 7
RF_CPG = 15
Applies to both low and high
current modes
OSC=0
OL
N
(f) = L(f) – 20log(N) – 10log(f
= 500 µA
Conditions
5
A
≤ +85˚C unless otherwise specified) (Continued)
COMP
) where L(f) is defined as the single side band phase noise
Min
50
10
50
50
50
50
Value
-200
-206
-208
-210
-214
Typ
20072172
Max
0.4
www.national.com
dBc/Hz
dBc/Hz
dBc/Hz
dBc/Hz
dBc/Hz
Units
ns
ns
ns
ns
ns
ns
V