speedy little buggers

[Jim Thompson]

;-)

Now why in the world would they make a nice chip like this:

http://www.onsemi.com/pub/Collateral/NLSF595-D.PDF

(especially nice in the 3mm x 3mm QFN-16 leadless package)

...with EIGHT manly 25mA+/7V sorta-open-drain outputs and then limit
the GND pin to a sissified 75mA maximum?

Best regards,
Spehro Pefhany

Spehro, You're mixing up MAXIMUM ratings (probably a device size
limitation) with normal operation... 12mA per output.

...Jim Thompson

 

[John Larkin]

;-)

Now why in the world would they make a nice chip like this:

http://www.onsemi.com/pub/Collateral/NLSF595-D.PDF

(especially nice in the 3mm x 3mm QFN-16 leadless package)

...with EIGHT manly 25mA+/7V sorta-open-drain outputs and then limit
the GND pin to a sissified 75mA maximum?

Because they expect that Real Men ignore abs max ratings?

Nice part, although you could usually just use an HC164 or something
like that to drive LEDs, and maybe save some money. Hey, that allows
you to drive half the LEDs as pullups and half as pulldowns.

John

 

[John Devereux]

Another thing, why call this rather general purpose device an
"tri-color LED driver"? It could do all kinds of other things.. it's
like a low-output-current version of this part:

http://focus.ti.com/lit/ds/symlink/tpic6c595.pdf

.. which is called a "power shift register".

Hey, thank's for that link, it looks a neat little chip. It's like the
combination of HC595 and ULN2803A that I use all the time, in one chip
(though a bit less output current of course). $0.39.

Actually I see there is a family of these things:

<http://www.scanti.ru/docs/html/tables/powerplus_logic_1.html>

Output currents up to 350mA.

 

[Jonathan Kirwan]

Actually I see there is a family of these things:

<http://www.scanti.ru/docs/html/tables/powerplus_logic_1.html>

Or just:

http://focus.ti.com/docs/search/paramsearch.jhtml?tfsection=param_table&templateId=5255&familyId=356

for the TI page, I think.

Jon

 

[Spehro Pefhany]

Hey, thank's for that link, it looks a neat little chip. It's like the
combination of HC595 and ULN2803A that I use all the time, in one chip
(though a bit less output current of course). $0.39.

Actually I see there is a family of these things:

<http://www.scanti.ru/docs/html/tables/powerplus_logic_1.html>

Output currents up to 350mA.

Yup. The higher current ones have a different package but a similar
part number (20 pins). A good ground layout is essential at those
currents.

Best regards,
Spehro Pefhany