What are the modern options for current-boosting uC outputs?

The ULN2803 isn't gone, you know. Digi-key has them in DIP for $0.77, and the small-outline packages are even cheaper.

Cheers! Rich

=A0And

Yep, I noticed they're still available and cheap, so that's a good sign. I'm just trying to update myself on what else is out there, both individual drivers and (quad/hex/octal) packs, so I can make informed decisions rather than "I used these in 1983" decisions. :-) One sub-question I have is what would one use for an individual switch. Used to be an NPN (for sinking) or a PNP (for sourcing). I'm guessing FETs are the devices of choice now, but what types/families are plug-and-play with micro outputs?

Mike

Using a mosfet is more common now than it used to be. Make sure the gate cannot "float" to the wrong level during power on reset. There are also things like opto-fets which can provide simple isolated switching up to 1A or so (sink or source, ac or dc). I like these when I need a "universal" output, when you don't really know what the customer is going to use it for.

Also of course I still ye olde ULN2803!

Mike,

First off, you design any circuit usage as a function of the microprocessor output specs and the full loading specs.

There's a reason some parts are still being manufactured after 30 years or so. It's not likely they'll be going away soon, either.

As to modern devices, go to the tried and true sources and see what recommended replacement parts are listed. Almost every manufacturer has them for parts that have been superceded. You know the major players. Go to their pages and see what's on offer.

-- Ray

On a sunny day (Sat, 29 Dec 2007 11:01:16 -0800 (PST)) it happened Mike Silva wrote in :

Use an IRLZ34N MOSFET, it will switch several amps.

A dinky SOT-23 logic-level mosfet can be handy, like the FDV301. They cost about a nickel, saturate nicely all the way to ground, and you can plop them individually wherever needed.

There are similar p-channel parts, too.

John