![Texas Instruments TMS320TCI6482 Скачать руководство пользователя страница 12](http://html.mh-extra.com/html/texas-instruments/tms320tci6482/tms320tci6482_design-manual_1094767012.webp)
www.ti.com
6.3.3.1
Single Device Solution
LOW JITTER
OSCILLATOR
Example:
Pletronics
LV77D
RIOCLK
DSP
RIOCLK
0.01uF
0.01uF
RIOCLK
DSP
LOW JITTER
OSCILLATOR
Example:
Pletronics
PE77D
150 ohm
150 ohm
0.01uF
0.01uF
RIOCLK
6.3.3.2
Fanout Solutions
Clocking
It is assumed that the source clock is an oscillator on the same board as the TMS320TCI6482. Use of
distributed clocks may require a jitter cleaner device such as the CDCM7005 (refer to
http://focus.ti.com/docs/prod/folders/print/cdcm7005.html
) or the CDCL6010. If an on-board oscillator is
used with one TMS320TCI6482 no other components should be needed except for terminations.
For the Serial rapid IO reference clock examples of appropriate oscillators are:
•
Pletronics LVDS LV77D oscillator
–
http://www.pletronics.com/pdf/LV77D%203.3v.pdf
•
Pletronics LVPECL PE77D oscillator
–
http://www.pletronics.com/pdf/PE77D%203.3v.pdf
These oscillators have not been tested but are examples of oscillators that meet the specification
requirements for RIOCLK/RIOCLK.
Figure 3
shows an LVDS based solution including terminations.
Figure 4
shows an LVPECL based
solution including terminations. The terminations shown are still being investigated and should be
considered preliminary.
Figure 3. RIOCLK Single Device LVDS Clock Solution
Figure 4. RIOCLK Multiple Devices LVDS Clock Solution
For systems with multiple TMS320TCI6482 devices it may be preferred to use one oscillator and a fanout
buffer instead of multiple oscillators. This would allow for fewer components as well as lower cost. The
fanout buffer increases the jitter at the clock input so care must be taken in selecting the combination of
oscillator and fanout buffer.
In most cases the same oscillators described in
Section 6.3.3.1
can be used for the fan out case. The
oscillator output specifications should be compared to the fanout buffer input specifications to make sure
they are compatible.
A low jitter fanout buffer is required which generally means a non-PLL based fanout buffers should be
used. Suggested solutions for a fanout buffers are:
12
TMS320TCI6482 Design Guide and Migration from TMS320TCI100
SPRAAC7B – April 2006
Submit Documentation Feedback