# can this led be powered off arduino digital pin?

can this led be powered off an arduino digital pin? http://www.vishay.com/docs/81009/tsal6100.pdf

think its max forward current is 100ma and has a forward voltage of 1.5. Not sure what its forward current is though Tanks for any help Tom

Sure, see figure 4. Pick a current limit resistor to keep current ~ 20mA to keep with Atmega328P limits. (5V - 1.2V Vf)/.02A = 190 ohm 5V could be as low as 4.2V, measure & see what your device is putting out, adjust the resistor value accordingly, could be as low as: (4.2V - 1.2V)/.02A = 150 ohm

think its max forward current is 100ma

You could power it off an I/O pin, up to the pin's absolute maximum current of 40mA, but it wouldn't be as bright as it could be.

Awesome guys thanks for the advice!

Awol is correct but he forgot to add up to 40 ma with current limiting or you will kill your pin.

cjdelphi: Awol is correct but he forgot to add up to 40 ma with current limiting or you will kill your pin.

No, he didn't forget - that's what "up to the pin's absolute maximum current of 40mA" means - the current limit is implicit.

AWOL:

cjdelphi: Awol is correct but he forgot to add up to 40 ma with current limiting or you will kill your pin.

No, he didn't forget - that's what "up to the pin's absolute maximum current of 40mA" means - the current limit is implicit.

The pin will max out and supply possibly higher current than that for a while.

And the Titanic was afloat for a while.

cjdelphi:

AWOL:

cjdelphi: Awol is correct but he forgot to add up to 40 ma with current limiting or you will kill your pin.

No, he didn't forget - that's what "up to the pin's absolute maximum current of 40mA" means - the current limit is implicit.

The pin will max out and supply possibly higher current than that for a while.

And there was me, thinking that "up to" excluded "greater than".

Above 20mA, 4.2V out is not guaranteed, so choice of resistor value will have to be determined experimentally:

1. Although each I/O port can source more than the test conditions (20mA at VCC = 5V, 10mA at VCC = 3V) under steady state conditions (non-transient), the following must be observed: If IOH exceeds the test condition, VOH may exceed the related specification. Pins are not guaranteed to source current greater than the listed test condition.

VOH, Output High Voltage, with IOH = -20mA, VCC =5V : 4.2V min