Datasheet

FREQUENCY (MHz)
PHASE NOISE (dBc/Hz)
-158
-154
-150
-146
10 100
-162
1000
OFFSET (Hz)
PHASE NOISE
(dBc/Hz)
-150
-140
-130
-120
-110
-100
-90
1.E+02 1.E+03 1.E+04 1.E+05
-160
1.E+06 1.E+07 1.E+08
VCO_DIV = 5
VCO_DIV = 2
VCO_DIV = 1
VCO_DIV = 3
VCO_DIV = 4
VCO_DIV = 6
LMX2541SQ2060E, LMX2541SQ2380E
LMX2541SQ2690E, LMX2541SQ3030E
LMX2541SQ3320E, LMX2541SQ3740E
www.ti.com SNOSB31I –JULY 2009–REVISED FEBRUARY 2013
Typical Performance Characteristics (Not Guaranteed) (continued)
Divider Noise Floor
vs.
Divider Value
(f
VCO
= 3700 MHz, Various values for VCO_DIV)
When the divider is engaged (VCO_DIV >0), then the entire system phase noise is reduced by a factor of 20 × log(VCO_DIV). However, the
noise floor of the divider will also add to this noise as is visible at far offsets. Note that the noise floor for Bypass mode is lower because the
VCO divider is not engaged.
Figure 6.
Divider Noise Floor
vs.
Frequency
Provided the VCO divider is not bypassed, the actual value of it does not impact the divider noise floor; it is the frequency at the RFout pin
that impacts the divider noise floor. The above plot shows how this noise floor changes as a function of the frequency of the RFout pin.
Figure 7.
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Product Folder Links: LMX2541SQ2060E LMX2541SQ2380E LMX2541SQ2690E LMX2541SQ3030E
LMX2541SQ3320E LMX2541SQ3740E