Chip on Stalker VERY HOT....did I destroy it?

I recently received my Seeeduino Stalker V1 (328P). I have been playing around with the RTC, SD Card, and XBee functions. So far everthing seems to work great.

However, today I had my Stalker connected to the UartSBee with nothing else connected (except for an SD Card) and I touched a small chip and burned my finger! This little chip was so hot that I couldn’t touch it for more than about 1/2 a second!

I’ve circled the chip in question in the picture below. From the schematic, I believe this is the PCA9306 which is a level shifter chip. Is this correct? If so, I have to assume that I’ve somehow destroyed the chip. Any idea how I might have done that? I don’t really understand what the chip is good for, so I’m not sure what impact it will have on my projects.

Any help you can provide would be appreciated.


I have a similar problem with my Stalker bought in December with date code 12.18.2009.
Furthermore, it is not possible to upload programs anymore. Receiving the out of sync message!
Looking forward to a reply from the Seeedstudio people.

I’m glad I’m not the only one!

This happened to me yesterday, having had no problems whatsoever in the preceding few weeks of operation. It’s been happily running functions involving the RTC, microSD, and LCD screen and temp sensors (all on USB power through UartSBv3.1 so far). Mine is also a Stalker v328 with date code 12.18.2009.

Now, whenever I switch it on (with or without anything else connected to the board), this component heats up intensely; after a few seconds it’s too hot to touch. I’m not really sure what this component does. The board appears to be functioning okay apart from that, at least until I lose my nerve and disconnect it again.

Is this board now effectively dead? Will Seeed replace it?

Looking forward to a reply.

For what it’s worth, I replaced the PCA9306 and the RTC (DS1307) and the RTC still does not work. Granted, my surface mount soldering skills are not very good, but I’m pretty sure I got them on there correctly. The good news is that the PCA9306 no longer gets hot. So what else could be wrong? I suppose it could be any number of things. If I get some time I’ll start poking around some more.

I think it’s not worth. Is it fair to start to resolder a brand new board that have a defect. More people have experienced this issue, and I have tried a couple of times to address the problem with seedstudio, but no one has bothered to answer yet.
I cannot figure out the problem, have tried most of the parameters in connection, as type of board, comm. port, speed and voltage logic (5 volt as in the datasheet) but the board still has a very hot IC and it is not possible to upload any code, receive the message, out of sync. Though for the first couple of times some test could be uploaded, as I said, I cannot figure out the problem.
There is no question, the board is defect and I believe it’s due for a replacement, which should part of a god service offer from the vendor (Seeedstudio).
I too look forward to a reply.

Mine is currently managing some operations, but not all. I can upload sketches okay. Blink works fine, and reading from the microSD works fine. However, most of the output operations seem dead - I can no longer write to microSD or LCD.

I also submitted a query to customer services a few days ago, but haven’t heard back yet (though to be fair, they have been closed for a few days over chinese new year).

Hi Guys,
We are sorry for late response.
Yes, the Chip is PCB9306 level Shifter.
Effect is:
I2C communication, short the power.
Result is:
I2C not work(cannot read the RTC…);
Dim power LED;
Cannot upload sketch…

This Problem appeared in our test, but just a few of them(5/300);
But now, it seems a big and serious problem.
We have check the schematic and PCA9306 datasheet, and found out the problem maybe the UartSB voltage which is direct come from USB port.
If the USB port Voltage is more than 5V, it will burn this chip, and it will not come back to work anymore.

Here has a solution to avoid the USB power, power the Stalker V1 from EXT JST power Jack, and toggle the UartSB power switch to 3.3V side.
As the EXT power has a Diode in Series, the supply just 4.6~4.8V, it is safe for PCB9306.

For the burned customer,
Please contact our Product Engineer kevin.hai{at} for a replacement.

Much sorry for the bothering.


Thanks for your reply. I have contacted your engineer as you mentioned.

I haven’t been able to test your alternative method fully yet, as I don’t have an external power supply to hand just now. Using a 9V battery powered up the board okay, but the 5V rail is only hitting 3-4V - not enough to run my LCD screen. Although I guess it’s not a fair test when the board has a damaged component.

Out of interest, does the stalker v2 use the same component?



Maybe the 9V battery cannot drive up the LCD back light.
Actually, we have redesign the Stalker, replace the Level Shifter IC to a Dual-N-MOS(AN97055:;
As Chinese new year vacation, our Product Engineer is not back, yet. Please wait a while.