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

[James Patchell]

Too bad about them being out of stock.  So goes the give and take with surplus.

At 11:18 AM 11/15/2003 -0800, Scott Stites wrote:
>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
> > >
> > > ***************************************************
> > >
> > >
> > >
> >
> >

         -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

***************************************************