TMS320C6713B Floating-Point Digital Signal Processor (Rev. A)
TMS320C6713B Floating-Point Digital Signal Processor (Rev. A)
TMS320C6713B Floating-Point Digital Signal Processor (Rev. A)
You also want an ePaper? Increase the reach of your titles
YUMPU automatically turns print PDFs into web optimized ePapers that Google loves.
SPRS294A − OCTOBER 2005 − REVISED NOVEMBER 2005<br />
power-supply design considerations<br />
A dual-power supply with simultaneous sequencing can be used to eliminate the delay between core and I/O<br />
power up. A Schottky diode can also be used to tie the core rail to the I/O rail (see Figure 22).<br />
I/O Supply<br />
DVDD<br />
Core Supply<br />
Schottky<br />
Diode<br />
C6000<br />
DSP<br />
CVDD<br />
VSS<br />
GND<br />
Figure 22. Schottky Diode Diagram<br />
Core and I/O supply voltage regulators should be located close to the DSP (or DSP array) to minimize<br />
inductance and resistance in the power delivery path. Additionally, when designing for high-performance<br />
applications utilizing the C6000 platform of DSPs, the PC board should include separate power planes for<br />
core, I/O, and ground, all bypassed with high-quality low-ESL/ESR capacitors.<br />
power-supply decoupling<br />
In order to properly decouple the supply planes from system noise, place as many capacitors (caps) as possible<br />
close to the DSP. Assuming 0603 caps, the user should be able to fit a total of 60 caps — 30 for the core supply<br />
and 30 for the I/O supply. These caps need to be close (no more than 1.25 cm maximum distance) to the DSP<br />
to be effective. Physically smaller caps are better, such as 0402, but the size needs to be evaluated from a<br />
yield/manufacturing point-of-view. Parasitic inductance limits the effectiveness of the decoupling capacitors,<br />
therefore physically smaller capacitors should be used while maintaining the largest available capacitance<br />
value. As with the selection of any component, verification of capacitor availability over the product’s production<br />
lifetime needs to be considered.<br />
94 POST OFFICE BOX 1443 • HOUSTON, TEXAS 77251−1443