CS2000-OTP_09 Datasheet, PDF (22/30 Pages) Cirrus Logic – Fractional-N Clock Synthesizer & Clock Multiplier

CS2000-OTP
6. PARAMETER DESCRIPTIONS
As mentioned in Section 5.1 on page 11, there are two different kinds of parameter configuration sets, Modal and
Global. These configuration sets, shown in Figure 17, can be programmed in the field using the CDK2000 or pre-
programmed at the factory. Please see “Programming Information” on page 27 for more details.
M[1:0] pins
Modal Configuration Set #0
Ratio 0
RModSel[1:0] AuxOutSrc[1:0] LockClk[1:0]
FracNSrc
00
Modal Configuration Set #1
Ratio 1
RModSel[1:0] AuxOutSrc[1:0] LockClk[1:0]
FracNSrc
01
Modal Configuration Set #2
Ratio 2
RModSel[1:0] AuxOutSrc[1:0] LockClk[1:0]
FracNSrc
10
Modal Configuration Set #3
Ratio 3
RModSel[1:0] AuxOutSrc[1:0] LockClk[1:0]
FracNSrc
11
Global Configuration Set
AuxLockCfg
RefClkDiv[1:0]
ClkOutUnl
LFRatioCfg
M 2C onfig [2 :0 ]
ClkIn_BW[2:0]
Figure 17. Parameter Configuration Sets
6.1 Modal Configuration Sets
There are four instances of each of these configuration parameters. Selection between the four stored sets
is made using the M[1:0] pins.
6.1.1
R-Mod Selection (RModSel[1:0])
Selects the R-Mod value, which is used as a factor in determining the PLL’s Fractional N.
RModSel[1:0]
00
01
10
11
Application:
R-Mod Selection
Right-shift R-value by 1 (÷ 2).
Right-shift R-value by 2 (÷ 4).
Right-shift R-value by 3 (÷ 8).
Right-shift R-value by 4 (÷ 16).
“Ratio Modifier (R-Mod)” on page 15
Note: This parameter does not take affect unless M2 pin is high and the M2Config[2:0] global param-
eter is set to ‘011’.
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