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Topic: Quick Q about discrete transistor vs. arrays (Read 543 times) previous topic - next topic

Chris L

Feb 27, 2009, 01:16 pm Last Edit: Feb 27, 2009, 01:19 pm by csl Reason: 1
Hi folks,

I'm currently using a small TIP102 Darlington transistor for my needs, but will need to scale this up 13x, so I thought I'd probably be better of with a couple of 8-way Darlington arrays instead. Please can you advise me on whether this is correct:

I'm using this chip (probably overkill for my needs, current-wise, not to mention expensive) -- could I substitute this array for a bunch of TIP102? Using them to switch 12v solenoids on.

halley

#1
Feb 27, 2009, 01:34 pm Last Edit: Feb 27, 2009, 01:36 pm by halley Reason: 1
Read your datasheet, not just for the current rating of each pin, but the current rating of all pins combined (usually less than you think), and also for the heat dissipation.  If you're clacking one solenoid at a time for bursts, it might serve well.  If you're clacking them all at random or for sustained periods, you'll probably need to use individual transistors, and maybe even with a heatsink.

I made a board that will talk i2c to control eight hexfet transistors for solenoid driving.  It's still in testing now.

Chris L

Thanks Ed -- it's just be for 12ms bursts, so I'm hoping I should be okay with a relatively lightweight array. :) Not enough time for much of a heat build-up. Shall pore over some datasheets!

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