I searched the forum but didn't find this. Can someone clear this up for me. I've always taken the maximum current of the darlington drivers as used in the project boards as 500mA maximum total current and that's what I've always understood, but if you read the datasheet it's a bit confusing.
From Picaxe website - 18m2 project board:
Quote:
The board is supplied with all essential PCB components including IC and download sockets plus a ULN2803A Darlington driver buffer chip that enables you to connect higher power output devices (such as motors, solenoids, relays) directly to the board (current up to 500mA).
From datasheet for darlington driver:
Quote:
The ULN2801A-ULN2805A each contain eight darlington transistors with common emitters and integral suppression diodes for inductive loads. Each darlington features a peak load current rating of 600mA (500mA continuous) and can withstand at least 50V in the off state. Outputs may be paralleled for higher current capability.
It's confusing as to what they mean by 'Darlington' as both the whole component and the individual transistors inside are being called 'Darlingtons'. If each individual darlington transistor of the 8 total can have a peak load of 500mA and two can be linked together for higher current draw, that would suggest a total maximum load of 4 Amps but I'm assuming that's not right as that's not what the graphs show.
But in that case what do they mean by "Outputs may be paralleled for higher current capability"?
I assume you can spread the 500mA over 1 output or 8 as long as you don't exceed the maximum.