Datasheet

LMX2541SQ2060E, LMX2541SQ2380E
LMX2541SQ2690E, LMX2541SQ3030E
LMX2541SQ3320E, LMX2541SQ3740E
SNOSB31I –JULY 2009–REVISED FEBRUARY 2013 www.ti.com
Register R2
This word contains all the bits of the fractional denominator. These bits apply if the device is being used
fractional mode.
PLL_DEN[21:0] -- Fractional Denominator
These bits determine the fractional denominator.
PLL_DEN[21:0]
Fractional
Denominator
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
... . . . . . . . . . . . . . . . . . . . . . .
4194303 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1
Registers R1 and R0
Both registers R1 and R0 contain information for the PLL R counter, N counter, and fractional numerator. The
action of programming register R0, even to the same value, runs the VCO calibration when the device has the
internal VCO operating. There are some programming words that are split across these two registers.
PLL_R[11:0] -- PLL R Divider Value
The R divider divides the OSCin signal. Note that if the doubler is enabled, the R divider is bypassed.
PLL_R[11:0]
0 Illegal State
1 0 0 0 0 0 0 0 0 0 0 0 1
2 0 0 0 0 0 0 0 0 0 0 1 0
3 0 0 0 0 0 0 0 0 0 0 1 1
... ... ... ... ... ... ... ... ... ... ... ... ...
4095 1 1 1 1 1 1 1 1 1 1 1 1
PLL_N[17:0] PLL N Divider Value
When using integer mode, the PLL N divider value is split up into two different locations. In fractional mode, only
the 12 LSB bits of the N counter are used. Based on the order of the modulator, the range is shown in the table
below.
PLL_N[17:12] PLL_N[11:0]
<12 Divide Values below 12 are prohibited
12 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 0 0
Intege
13 r 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 0 1
Mode
... . . . . . . . . . . . . . . . . . .
262143 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1
12 Possible with first order modulator only
13-14 Possible with first or second order modulator
15-18 Possible with first, second, or third order modulators only
19 x x x x x x 0 0 0 0 0 0 0 1 0 0 1 1
... Fracti . . . . . . . . . . . . . . . . . .
onal
4087 x x x x x x 1 1 1 1 1 1 1 1 0 1 1 1
Mode
4088 Possible with a first, second, or third order modulator only
-4091
4092- Possible with a first or second order modulator only
4093
4094 Possible with a first order modulator only
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Product Folder Links: LMX2541SQ2060E LMX2541SQ2380E LMX2541SQ2690E LMX2541SQ3030E
LMX2541SQ3320E LMX2541SQ3740E