Is a DM13A capable of running 32 Amber LED's, 2 per pin. I looked at the datasheet but honestly I can't make head nor tail of it.
In theory, yes, I think so.
In practice I'm not sure how well it would work in an Arduino circuit.
How are you planning to connect the LEDs? What is the forward voltage of the LEDs?
If you connect pairs of LEDs in parallel, there's no guarantee they will share the current equally, which could lead to unequal brightness and the early failure of one of the pair. If you use LEDs from the same batch (made by the same factory on the same day) that should minimise that risk.
If you connect pairs of LEDs in series, and the forward voltage of each led is, say, 2.2V, then 5V supply might not be enough, because it's only 0.6V above the combined forward voltage of the pair of LEDs, which feels too close to the minimum. But if you supply more than 5V, such as 6V, it would be 1.6V above the combined led forward voltage, which should be fine. But then the 5V data signals from the Arduino might not be high enough, because a HIGH input signal must be at least 0.8 of the supply voltage which is 4.8V. That's only 0.2V below the Arduino signal voltage, which may make the circuit unreliable.
I have not used this chip, but I'll take a SWAG (Scientific Wild-Assumed Guess) based on my experience with similar devices from years ago.
I think it should work well for your application. It functions as a constant current sink, meaning the LEDs are not powered directly by the chip but by an external voltage source. The chip just controls the current. This design allows you to use any voltage within the chip's specifications (up to about 17V max). The chip regulates the current by controlling how much current it sinks, and this value can be set as needed.
Make sure the grounds for the LED power supply, the chip, and the Arduino are all connected. You can use combinations of both parallel and series LEDs. When connecting LEDs in parallel, you need to place a resistor in series with each LED string to balance the current. You can also create parallel-series strings if needed.
Please post the datasheet for the LED you plan to use.
Which Arduino are you using?
Which DM13A package do you plan to use (there are 4 types)?
What is the power source for the LEDs?
I don't have a datasheet for the LEDs, they came as part of a package, I'm using a Mega 2560 R3 and the the IC is DM13A code on it is B22052213G. The power source for the LEDs is a 5v 10A PSU and 5v from Arduino for the DM13As.
I don't think I need a resistor for the LEDs as the DM13A has a REXT pin for the current limiting resistor.
Then we have no way of knowing if it will work or not.
Do you know the maximum forward voltage and current at that voltage?
If not then you will just have to try and see.
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