Searching \ for '[EE] 3.3v Octal Relay Driver, preferably through-h' in subject line. ()
Make payments with PayPal - it's fast, free and secure! Help us get a faster server
FAQ page: massmind.org/techref/io/motors.htm?key=relay
Search entire site for: '3.3v Octal Relay Driver, preferably through-h'.

Exact match. Not showing close matches.
PICList Thread
'[EE] 3.3v Octal Relay Driver, preferably through-h'
2009\06\04@040846 by Forrest W Christian

flavicon
face
I'm needing to drive 4 latching relays with 3.3V (8 total coils).  
Low-side switching is ok.  The relay I'm looking at is rated for 66.7mA
of operating current.

It looks like the ULN280x series could be used at 3.3V, except that the
Vce(sat) is over a volt, and the relay has a minimum voltage rating of
2.25V.

What I'd really like to find is the equivalent of eight 2n7000's with
integral snubber diodes in a DIP package.

Cheap is always good :)

And no, I don't have 5V available.

-forrest


2009\06\04@080452 by Isaac Marino Bavaresco

flavicon
face
Forrest W Christian escreveu:
> I'm needing to drive 4 latching relays with 3.3V (8 total coils).  
> Low-side switching is ok.  The relay I'm looking at is rated for 66.7mA
> of operating current.
>
> It looks like the ULN280x series could be used at 3.3V, except that the
> Vce(sat) is over a volt, and the relay has a minimum voltage rating of
> 2.25V.
>
> What I'd really like to find is the equivalent of eight 2n7000's with
> integral snubber diodes in a DIP package.
>
> Cheap is always good :)
>
> And no, I don't have 5V available.
>
> -forrest
>  

Usually the data-sheet shows the worst case Vce(sat) with a high
current. The Vce(sat) for smaller currents are generally much less than
what is in the data-sheet. Good data-sheets show a graphic of Vce(sat) x
Ic x Ib.

Regards,

Isaac

__________________________________________________
Faça ligações para outros computadores com o novo Yahoo! Messenger
http://br.beta.messenger.yahoo.com/

2009\06\04@144259 by Dwayne Reid

flavicon
face
At 06:04 AM 6/4/2009, Isaac Marino Bavaresco wrote:

>Forrest W Christian escreveu:
> > I'm needing to drive 4 latching relays with 3.3V (8 total coils).
> > Low-side switching is ok.  The relay I'm looking at is rated for 66.7mA
> > of operating current.
>
>Usually the data-sheet shows the worst case Vce(sat) with a high
>current. The Vce(sat) for smaller currents are generally much less than
>what is in the data-sheet. Good data-sheets show a graphic of Vce(sat) x
>Ic x Ib.

Yeah - but the uln280x are darlington transistors.  You just ain't
gonna get much less than 1V saturation.

Forrest - I know that you asked for drivers, but how about an SPI
part with integrated DMOS output transistors?  We use the TPIC family
a LOT here - TPIC6595 and TPIC6C595.  Avoid the TPIC6B595 - we've had
nothing but grief with them.

TPIC6C595 is in a 16 pin DIP package and is good for 100mA continuous
per output.  TPIC6595 is in a 20 pin package and is good for 250mA
continuous per output.  You also don't need clamp diodes on the relay
coils - the devices are rated for inductive use and contain circuitry
to cause avalanche at about 60V peak.

We've used many thousands of these with no problems.  We often drive
them from a tiny PIC - each of the 3 SPI control lines can be shared
with switches or an analog input or two.

Hope this helps!

dwayne

--
Dwayne Reid   <spam_OUTdwaynerTakeThisOuTspamplanet.eon.net>
Trinity Electronics Systems Ltd    Edmonton, AB, CANADA
(780) 489-3199 voice          (780) 487-6397 fax
http://www.trinity-electronics.com
Custom Electronics Design and Manufacturing

More... (looser matching)
- Last day of these posts
- In 2009 , 2010 only
- Today
- New search...