spartan3 kit voltage problem

Hello,
I am doing a FPGA kit using Xilinx XC3s200PQ208.
When VCCO0~7 are connected to 3.3v,the current is about 2.5A and voltage drop from 3.3v to 1.4v.
VCCAUX is 2.5v @ 170mA.
VCCINT is 1.2v @ 35mA, which I think are normal.
I checked the power pins they are all connected correctly.
And the other pins are all unconnected except configuration pins.
The resistance between VCCIO and GND is 12K when no power connected but when connected to 3.3V it seems to be 1.4V/2.5V<1ohm.
So where am I wrong? Any one could give me some suggestions?
best regards

hi there

your fpga is probably overloading,
the fpga is like a short to the gnd....
and that's why the voltage drop down and the current goes higher (ohm's law)
and the only thing limits the current is the interal impedance of your p.s....

all you need to do is to replace the fpga chip, that will probably solve it...
UNLESS you have few more chips connected to the voltage supply line
so you will need to disconnect them one by one and check if there is still
0 ohm on your VCC pins................

good luck...

Added after 1 minutes:

hi there

your fpga is probably overloading,
the fpga is like a short to the gnd....
and that's why the voltage drop down and the current goes higher (ohm's law)
and the only thing limits the current is the interal impedance of your p.s....

all you need to do is to replace the fpga chip, that will probably solve it...
UNLESS you have few more chips connected to the voltage supply line
so you will need to disconnect them one by one and check if there is still
0 ohm on your VCC pins................

good luck...

Added after 7 minutes:

hi there

your fpga is probably overloading,
the fpga is like a short to the gnd....
and that's why the voltage drop down and the current goes higher (ohm's law)
and the only thing limits the current is the interal impedance of your p.s....

all you need to do is to replace the fpga chip, that will probably solve it...
UNLESS you have few more chips connected to the voltage supply line
so you will need to disconnect them one by one and check if there is still
0 ohm on your VCC pins................

good luck...

I am assuming that you have a Spartan 3 Starter Kit from DigilentInc (or from Xilinx via an indirect order)..

please clarify a few things...

1. Was it working previously? has it ever worked?

2. are the jumpers connected properly? do you know where which jumper goes?

3. do you know how to use the kit? what exactly does the problem appear like? PC (Impact) not detecting the kit? or what?

hi zeeshanzia84
i am doing my own kit not the startkit provided by xilinx.thanks for your help.
i just wonder is fpga chip are so easy to demage if the voltage are out of range a little while .

yes, FPGA chips is easy to danage, if do your own board, I would recomend first put all power supplies, so you can debug them, without damaging hard to solder expensive IC, and when you absolutlly sure, all of your power supply, are capable of providing requred current, able to start witin limits of start up time and sequence, than you can start puting ICs

god lack, and I think you need to replace your Xilinx

hi

you can design for the next time some voltage regulator or LDO
that will be able to provide all your needed voltages by single chip.

go to TI website / power supplies , they have Simple Voltage regulator
that provide all the voltages you need.........


best regards.

Added after 1 minutes:

hi

you can design for the next time some voltage regulator or LDO
that will be able to provide all your needed voltages by single chip.

go to TI website / power supplies , they have Simple Voltage regulator
that provide all the voltages you need.........


best regards.

Added after 3 minutes:

hi

you can design for the next time some voltage regulator or LDO
that will be able to provide all your needed voltages by single chip.

go to TI website / power supplies , they have Simple Voltage regulator
that provide all the voltages you need.........


best regards.

hi bmwcoupe,
thanks, i check it the power supply they are all right when no xilinx chip on it.
(LM1086cs-3.3 for 3.3v ,LM1086cs-2.5 for 2.5v, TPS78601 for 1.22v),when i put the chip the probelm happened.Is it any thing ralated with configuration part?