My chip is burned down, need your help!

[welton]

Hi all,
My chip is burned down, it was burned after a long operation during tests. It's a 1A charger IC. I have tested several tens chips, but 2 were damaged. I saw Supply current is current limited by my setting(2A), VBAT current is ~30mA, and then chip was burned down.
1) Could you help me to figure out what're the causes in your experience?
2) Will latch-up result in this condition? When the circuit might cause latch-up condition, will all chips fabricated latched-up?
3) When lath-up condition happens in some chip, will this chip be damaged and never be powered up or never works?
Thanks for your help.

 

[fragment]

1. Check layout of your pcb-board. Improper layout can lead to voltage or current spikes.
2. Check inductor for saturation.
3. Check temperature of chip and other components
4. Find latch-up current for every pin of your chip. It must be at least 100 mA
5. Ask your foundry results of OLT (operation life test) for every element of technology

 

[welton]

Hi fragment,
I am sorry I didn't describe in detail.
The situation is, when I was doing short circuit TESTs, the IC is biased at trickle condition.
1) VIN=+5V, VBAT=0V(in trickle charge condition), TEMP=1.5V(normal condtion).
2) I used a metal wire to short VBAT and TEMP, there is a large current(2A, current limited by 1.5V supply) flow into E-load. This should be normal condition because E-load should sink the current.
3) When I try to touch on and off the metal wire(to let the VBAT and TEMP switch between short and open condition), IC was burned down. I de-cap the IC and found the damaged place is near the Source of the power PMOS.
I have no idea why it happened because during normal operations, the current is more then 1A, and the chip works well.
Please help me.
Thank you very much!

 

[FvM]

I don't see, how the issue can be discussed seriously without knowing the device circuit and the test setup.