Digital pin - current figure?

24 Nov 2009

Can someone please confirm the source and sink capability of the digital I/O pins. Your technical reference page for the LPC1678 says 40mA (400mA total), however the manufacturers datasheet states 4mA minimum (ref Table 6: static Characteristics) but no maximum figure.

How confident are we that driving a 40mA load with one pin won't cause any damage???



ps. Anyone got any figures for the drive capability of AnalogOut?

24 Nov 2009

Hi Chris,

I just checked out this document :

Page 40, Table 6, under "Standard port pins" states that you can source upto 45mA and sink upto 50mA under short crcuit conditions. I've certainly drived LEDs with series resistors to about 30mA with no problems.

Page 38, Table 4, states that the maximum current is 100mA per pin for both the supply and the ground, as there are 4 VSS/VDD pins, the maximum is 400mA.

Page 63. Table 19 Has all the DAC output data.

Hope that helps.