TMS320C6745DPTP3 datasheet(69/227 Pages) TI1

69 / 227 page

OSCOUT

OSCIN

OSCVSS

ClockInput

toPLL

TMS320C6745, TMS320C6747

www.ti.com

SPRS377F – SEPTEMBER 2008 – REVISED JUNE 2014

6.5

Crystal Oscillator or External Clock Input

The C6745/6747 device includes two choices to provide an external clock input, which is fed to the on-

chip PLL to generate high-frequency system clocks. These options are illustrated in Figure 6-6 and

Figure 6-7. For input clock frequencies between 12 and 20 MHz, a crystal with 80 ohm max ESR is

recommended. For input clock frequencies between 20 and 30 MHz, a crystal with 60 ohm max ESR is

recommended. Typical load capacitance values are 10-20 pF, where the load capacitance is the series

combination of C1 and C2.

The CLKMODE bit in the PLLCTL register must be 0 to use the on-chip oscillator. If CLKMODE is set to 1,

the internal oscillator is disabled.

•

Figure 6-6 illustrates the option that uses on-chip 1.2V oscillator with external crystal circuit.

•

Figure 6-7 illustrates the option that uses an external 1.2V clock input.

Figure 6-6. On-Chip 1.2V Oscillator

Table 6-2. Oscillator Timing Requirements

PARAMETER

MIN

MAX

UNIT

fosc

Oscillator frequency range (OSCIN/OSCOUT)

MHz

Peripheral Information and Electrical Specifications

Submit Documentation Feedback

Product Folder Links: TMS320C6745 TMS320C6747

TMS320C6745DPTP3 Datasheet(PDF) 69 Page - Texas Instruments