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

[Mike Silva]

In the past I've used both individual transistors (bipolar) and
devices like the ULN2803 to allow uC outputs drive loads in the tens
to hundreds of mA. Being mostly a software person I haven't kept up
to date with what's available now for such uses, so I thought I'd get
reaquainted. What are the common choices today for driving loads
between, say, 25 and 250 mA? Small and cheap (and available) is
always good, of course. And I'm interested in knowing about both
sinking and sourcing current. Thanks.

Mike

 

[Jamie]

Mike Silva wrote:

In the past I've used both individual transistors (bipolar) and
devices like the ULN2803 to allow uC outputs drive loads in the tens
to hundreds of mA. Being mostly a software person I haven't kept up
to date with what's available now for such uses, so I thought I'd get
reaquainted. What are the common choices today for driving loads
between, say, 25 and 250 mA? Small and cheap (and available) is
always good, of course. And I'm interested in knowing about both
sinking and sourcing current. Thanks.

Mike
Still the transistor

only today, Logic enhanced mode fets are more attractive for
low loss of power..
With these devices, the Ron ( On resistance ) in very low! Like
in the mohms. (milli ohms), something that bipolar isn't as good
at. This allows you to run higher currents with no heat sinking and
requires only voltage to turn it on.
P.S.
They tend to be slightly slower on the switching how ever compared
to bipolar. You need to shop around for a low capacitance fet and
drivers if this is an issue.


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