EngIP 31 Posted May 27, 2011 Share Posted May 27, 2011 As the title suggest, I'm wondering if the valueline chips outputs are current limited? I've seen a graph in the datasheet showing output voltage drop Vs output current, and somehow I've read this to mean that the output current is limited. I've left a G2211 driving an LED for hours to see if it caught fire, and it never, so I'm sure the current is limited, but I'd like to see if anyone could refer me to some official documentation to either confirm or deny. Many thanks Guy Quote Link to post Share on other sites
NatureTM 100 Posted May 27, 2011 Share Posted May 27, 2011 The other day I was driving some transistors, and I forgot to put a resistor between the base of the transistor and the MSP430 pin -- effectively a short. It took awhile, but I ended up frying the port. I could run and upload code and stop at breakpoints, but toggling pins didn't have an effect on the output. When I realized my mistake, I touched the MSP and it was pretty warm. I don't know if this really answers your question, but it seemed worth mentioning. EngIP 1 Quote Link to post Share on other sites
cde 334 Posted May 27, 2011 Share Posted May 27, 2011 Current is practically limited by it's voltage drop. At 6ma (Per pin, 48ma per port), the valueline chips drop 0.3v. Too much current draw, and the voltage drops enough to make the pin useless. Current is not physically limited by the chip. Always use resistors. EngIP, SouLSLayeR, jsolarski and 2 others 5 Quote Link to post Share on other sites
zeke 693 Posted May 27, 2011 Share Posted May 27, 2011 Yeah, I smoked a port pin on a g2231 recently when I tried to make it pull down a 5V line - active low style. It wasn't happy. It got real hot. I had to replace it then redesign the circuit. If you try to pull a pin above 4.3V then the protection diode will get damaged. That's 3.6V + 0.7V for reference. RobG and EngIP 2 Quote Link to post Share on other sites
EngIP 31 Posted May 27, 2011 Author Share Posted May 27, 2011 Question answered - Thank you! Quote Link to post Share on other sites
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