ULN2803A help

[jeeep]

Hello,
I am running 4 LEDs per output on a ULN2803. Each segment of 4 LEDs is pulling 30mA @ 12vDC. So 30mA x 8 outputs = 240mA => 240mA/500mA (max ULN2803 output) = 48%.

Here is the datasheet (99kb): http://www.datasheetcatalog.org/datasheet/SGSThomsonMicroelectronics/mXysuw.pdf

Will this be fine? Does Figure 12 prove this? Thanks for any help.

 

[(*steve*)]

Figure 12 tells you that you can drive all 8 outputs at 120mA *each* at 50C.

It sounds like you are only driving them at 30mA (the LEDs are in series, right?) so you are a long way below the max spec of the device, unless you're going to be operating it at ambient temperatures above about 100C

 

[jeeep]

lol, thank you. It's clear I have not yet developed the skills necessary to decode simple chart diagrams. I was just looking for a chart to confirm that the 240mA would be fine over 8 outputs.

 

[(*steve*)]

Better safe than sorry