Forum Discussion
Altera_Forum
Honored Contributor
17 years agoMax 2 IC occasionally gets destroyed
In my hardware environment, a "Max 2" IC occasionally gets destroyed - it pulls down the 3.3 V power supply. What can be the cause for this? Can it be anything else than electrostatic discharge? The inputs of the IC have a voltage between 0 and 3.3 V (so this should do no harm).
14 Replies
- Altera_Forum
Honored Contributor
--- Quote Start --- Did you find solution to this problem? --- Quote End --- No, I did not. - Altera_Forum
Honored Contributor
--- Quote Start --- In my hardware environment, a "Max 2" IC occasionally gets destroyed - it pulls down the 3.3 V power supply. What can be the cause for this? Can it be anything else than electrostatic discharge? The inputs of the IC have a voltage between 0 and 3.3 V (so this should do no harm). --- Quote End --- I have the same problem on max V CPLD. All the power supply pins are short-ciruited to GND pin. I suspect te GND loop but it looks like it's not really repeatable, so far 3 CPLD have been burned during programming. Did you find solution to this problem? - Altera_Forum
Honored Contributor
- Altera_Forum
Honored Contributor
Hi,
Can you please draw a diagram and attach it to this disucssion? Thanks - Altera_Forum
Honored Contributor
--- Quote Start --- do you connect 0V or 3.3V first when you apply the power. --- Quote End --- I think that the potentials 0 V and 3.3 V only have a meaning if there is a voltage from one to another (or to a third potential in the device). So I don't understand the question and its aim. --- Quote Start --- What kind of voltage regulator do you have on the board? --- Quote End --- It is a low-dropout regulator: ADP3338. It is on a different board. --- Quote Start --- What is the source of all the inputs to the board? --- Quote End --- At present, there are only a bus (adresses, data, control signals - from a bus transceiver IC), 5 V (from a mains adapter) and 3.3 V (from the power regulator). - Altera_Forum
Honored Contributor
Oskar,
You say the MAXII device dies when the power is applied, do you connect 0V or 3.3V first when you apply the power. What kind of voltage regulator do you have on the board? What is the source of all the inputs to the board? Thanks - Altera_Forum
Honored Contributor
Thank you for your advice about ground loops.
--- Quote Start --- do you have boards that still survive ? --- Quote End --- Yes, I am working currently with a board which has obviously survived. --- Quote Start --- what is unclear now is, when will your maxII be destroyed. it can be destroyed during or after programming. --- Quote End --- I don't know exactly when it is destroyed. There are only few examples of this failure. Maybe it happend always when the boards were not in use for some time. Maybe the storage place for the boards is not quite ESD proof. I will have to keep observing this issue. --- Quote Start --- you say your maxII occasionally gets destroid. is it realy dead ? --- Quote End --- The current which flows through the destroyed board is more than 500 mA (even more than 2 A in the first moment after power-up). The voltage drops to 0.43 V within a few seconds. (The power supply can't provide enough power.) The Quartus programmer tells me: "Error: Can't access JTAG chain" Therefore I would say it's dead. - Altera_Forum
Honored Contributor
if there is a loop break it or make it as smal as possible.
if your designs get unstable with such loops then look at it again. whenever possible just connect everything to one pc and connect all devices on your setup to only one ac source. avoid a setup where pc with blaster is on ac phase 1 and scope on ac phase 2. i have seen currents on such gnd loops. this should not happen as you live in zürich and your equiment needs to meet certification procedures. what is unclear now is, when will your maxII be destroyed. it can be destroyed during or after programming. do you have boards that still survive ? i knew that cyclone III are more sensitive to the powersupply than cyclone II was. you say your maxII occasionally gets destroid. is it realy dead ? a had been seeking very long for the reason why some maxII epm570 devices do not work properly out of a production pcb set and with mysupport at the end it was a quartus setting and now ALL boards work fine. - Altera_Forum
Honored Contributor
--- Quote Start --- and for the last point, do you have some kind of GND Loop ? PC -> Blaster -> JTAG -> PCB -> any-Interface -> PC or via some kind of measurement device like scope ? --- Quote End --- The Byte Blaster is not connected most of the time, but there may be a ground loop sometimes, e.g. because of an emulator cable. Should I disconnect the emulator cable or the scope when the Byte Blaster is connected? I would find it rather awkward. Is there a more convenient method to avoid ground loops? - Altera_Forum
Honored Contributor
regarding power connection, it seems to be okay from schematic view, your pcb is another part how it is layouted from an SI oder EMI view.
regarding the io pins, they are fine from my side. and for the last point, do you have some kind of GND Loop ? PC -> Blaster -> JTAG -> PCB -> any-Interface -> PC or via some kind of measurement device like scope ? the GND potential of your scope is normaly PE what is GND on your PC (Blaster)