powering spartan IIe

[Goran]

Hi,
I'm building a simple board with Spartan IIE ( XC2S100E), and
wondering is it OK to derive power for VCCINT (1.8V) and VCCO (3.3V)
from something simple, such as LM317. I know it can source enough
current during start-up, but I'm not sure about voltage ramp, power
sequencing etc. Any hints are welcome.
Thanks in advance,
Goran

 

[Austin Lesea]

Goran,

If you place a 470uF, 680uF or a 1000 uF on the output of the LM317, you
should have enough stored charge to start up the Spartyan IIE.

Check out the app notes 450 and 451 which detail start up tricks.

Austin

Goran wrote:

Hi,
I'm building a simple board with Spartan IIE ( XC2S100E), and
wondering is it OK to derive power for VCCINT (1.8V) and VCCO (3.3V)
from something simple, such as LM317. I know it can source enough
current during start-up, but I'm not sure about voltage ramp, power
sequencing etc. Any hints are welcome.
Thanks in advance,
Goran