TMS320C6203B_15 Datasheet, PDF (37/109 Pages) Texas Instruments – FIXED-POINT DIGITAL SIGNAL PROCESSOR

TMS320C6203B
FIXEDĆPOINT DIGITAL SIGNAL PROCESSOR
SPRS086N − JANUARY 1999 − REVISED JULY 2006
clock PLL
Most of the internal C6203B clocks are generated from a single source through the CLKIN pin. This source clock
either drives the PLL, which multiplies the source clock in frequency to generate the internal CPU clock, or
bypasses the PLL to become the internal CPU clock.
To use the PLL to generate the CPU clock, the external PLL filter circuit must be properly designed. Figure 5,
and Table 15 through Table 17 show the external PLL circuitry for either x1 (PLL bypass) or x4 PLL multiply
modes. Figure 6 shows the external PLL circuitry for a system with ONLY x1 (PLL bypass) mode.
To minimize the clock jitter, a single clean power supply should power both the C6203B device and the external
clock oscillator circuit. Noise coupling into PLLF directly impacts PLL clock jitter. The minimum CLKIN rise and
fall times should also be observed. For the input clock timing requirements, see the input and output clocks
electricals section.
3.3 V
EMI Filter
PLLV
C3
10 mF
C4
0.1 mF
CLKMODE0
CLKMODE1
CLKMODE2†
CLKIN
PLLMULT
PLL
PLLCLK
CLKIN
LOOP FILTER
Internal to C6203B
1
CPU
0
CLOCK
(For the PLL Options
and CLKMODE pins setup,
C2
see Table 15 through Table 17)
C1
R1
† The CLKMODE2 pin is not available for the C6203B GNZ package.
NOTES: A. Keep the lead length and the number of vias between pin PLLF, pin PLLG, R1, C1, and C2 to a minimum. In addition, place all PLL
components (R1, C1, C2, C3, C4, and EMI Filter) as close to the C6000 DSP device as possible. Best performance is achieved with
the PLL components on a single side of the board without jumpers, switches, or components other than the ones shown.
B. For reduced PLL jitter, maximize the spacing between switching signals and the PLL external components (R1, C1, C2, C3, C4,
and the EMI Filter).
C. The 3.3-V supply for the EMI filter must be from the same 3.3-V power plane supplying the I/O voltage, DVDD.
D. EMI filter manufacturer: TDK part number ACF451832-333, 223, 153, 103. Panasonic part number EXCCET103U.
Figure 5. External PLL Circuitry for Either PLL Multiply Modes or x1 (Bypass) Mode
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