Followup: Re: [sdiy] MPQ2907 Quad Transistor Info?

[Scott Stites]

Hi Jim (and Synth-DIY gang),

I've been on the road a lot lately, and I finally have a chance to post the
follow-up to this email - Hosfelt had advertised the MPQ2907 transistor
package for pretty cheap.  I placed an order for 10 of them plus some other
stuff, but the order arrived a couple of weeks ago sans the chips - out of
stock, discontinued.  So, that pretty much nips the investigation of the
matching in the bud - for the price these chips go for at other sites, I'll
hand match my PNP's =0).

Take care,
Scott


----- Original Message -----
From: "Scott Stites" <scottnoanh at peoplepc.com>
To: <synth-diy at dropmix.xs4all.nl>; "James Patchell" <patchell at cox.net>
Sent: Monday, October 20, 2003 8:02 PM
Subject: Re: [sdiy] MPQ2907 Quad Transistor Info?


> Thanks, Jim!  It never occurred to me that they would actually not be on
the
> same substrate, but they sure look worth a try, and the thermal tracking
> would be a plus.
>
> They're certainly cheap enough (29 cents apiece at Hosfelt).
>
> Cheers,
> Scott
>
> ----- Original Message -----
> From: "James Patchell" <patchell at cox.net>
> To: "Scott Stites" <scottnoanh at peoplepc.com>;
<synth-diy at dropmix.xs4all.nl>
> Sent: Monday, October 20, 2003 6:13 PM
> Subject: Re: [sdiy] MPQ2907 Quad Transistor Info?
>
>
> > The MPQ2n2907 might be useful...but, the transistors are not on the same
> > substrate (they are individual die), and so you cannot guarantee any
sort
> > of matching at all....however...you would probably find that they are
> > matched more than good enough.  Most likely, the die all came from the
> same
> > wafer (but you cannot count on that), so, they are probably better
matched
> > than you would think.  Even when I purchase 2n3906's and set about to
> match
> > them...I am amazed at how often a batch of 20 or so will all be within
> > about 2 mV or so.  So, if they are cheap (like maybe 20 cents a dip, or
in
> > that range), give them a try.  Even though they are not on the same
> > substrate, they are in the same package and will probably thermal track
> > good enough.  However, they are not cheap (say $2 a dip)...I would say
> > forget it...and look into transistor arrays from THAT corporation...
> >
> > At 07:54 PM 10/20/2003 -0700, Scott Stites wrote:
> > >Hi list,
> > >
> > >I received my most recent Hosfelt catalog and ran across the quad PNP
> > >package MPQ2907N.  Since apparently the transistors are on the same
> > >substrate, could I assume they're reasonably matched?  I couldn't
really
> > >find much information on them on the web.  Any info would be
appreciated.
> > >
> > >Thanks,
> > >Scott
> >
> >          -Jim
> > ***************************************************
> > I'm a man
> > But I can change
> > If I have to
> > I guess.
> >
> > Man's Prayer
> > Red Green
> >
> > ***************************************************
> > http://www.oldcrows.net/~patchell
> >
> > http://members.cox.net/patchell
> >
> > ***************************************************
> >
> >
> >
>
>