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6.6.1
PLL1 and PLL2
PLLV
DD18
C2
C1
EMI Filter
+1.8 V
DM644x
PLL2
PLL1
0.1 μF
0.01 μF
TMS320DM6443
Digital Media System-on-Chip
SPRS282E–DECEMBER 2005–REVISED MARCH 2007
Table 6-12. PLL and Reset Controller Registers Memory Map (continued)
HEX ADDRESS RANGE
0x01C4 0D50
REGISTER ACRONYM
SYSTAT
DESCRIPTION
PLL Controller 2 System Clock Status 1 Register (Indicates SYSCLK on/off
Status)
Both PLL1 and PLL2 power is supplied externally via the 1.8 V PLL power-supply pin (PLLV
DD18
). It is
recommended that an external EMI filter circuit be added to PLLV
DD18
, as shown in
Figure 6-13
. The 1.8-V
supply of the EMI filter must be from the same 1.8-V power plane supplying the device’s 1.8-V I/O
power-supply
pins
(DV
DD
).
TI
recommends
EMI
NFM18CC222R1C3.
filter
manufacturer
Murata,
part
number
All PLL external components (C1, C2, and the EMI Filter)
should
be placed as close to the device as
possible. For the best performance, TI recommends that all the PLL external components be on a single
side of the board without jumpers, switches, or components other than the ones shown in
Figure 6-13
. For
reduced PLL jitter, maximize the spacing between switching signals and the PLL external components
(C1, C2, and the EMI Filter).
Figure 6-13. PLL1 and PLL2 External Connection
The minimum CLKIN rise and fall times should also be observed. For the input clock timing requirements,
see
Section 6.6.3
,
Clock PLL Electrical Data/Timing (Input and Output Clocks)
.
There is an allowable range for PLL multiplier (PLLM). There is a minimum and maximum operating
frequency for MXI/CLKIN, PLLOUT, and the device clocks (SYSCLKs). The PLL Controllers
must
be
configured not to exceed any of these constraints documented in this section (certain combinations of
external clock inputs, internal dividers, and PLL multiply ratios might not be supported).
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Peripheral and Electrical Specifications
105