ZX81 and 6116

[Richard Erlacher]

There were several makers that sported an xx15 type where the normal 16Kx1
dram was an xx16.  What these were, generally but not in all cases, were
products of a die shrink that resulted in a shorter refresh interval.  That
was certainly the case with the MOSTEK 4115's.  Those worked famously well in
applications like the Apple][ which was a big seller at the time.

more below ...

Dick

----- Original Message -----
From: "Pete Turnbull" <pete at dunnington.u-net.com>
To: <classiccmp at classiccmp.org>
Sent: Saturday, March 23, 2002 2:21 AM
Subject: Re: ZX81 and 6116


> On Mar 22, 22:43, Richard Erlacher wrote:
> > I guess I'm having a "senior moment" but I don't remember the 4118 at
> all,
> > though I definitely remember that there was such a thing.  Mostek made a
> > couple of pseudo-static RAM parts that were on a ~2716-compatible pinout.
>  Was
> > that one of them?  I've got some 1K- and 2K- byte parts from those days
> but I
> > don't remember the numbers right offhand.
> >
> > Perhaps someone could refresh my recollection.
>
> 4118 is the same pinout as a 2716 except that pin 21 is the /WR line
> instead of Vpp, and pin 19 is NC instead of A10.  It's a genuine static
> part, 1K x 8.  A 6116 is similar, but 2K x 8, with A10 on pin 19.  There
> are also low-power CMOS versions of the 6116.  Zilog made a "quasi-static
> RAM" 4K x 8, called Z8132, but it's 28-pin.  They also, confusingly, made
> 16-pin dynamic RAMs 8K x 1 and 16K x 1 called Z6115 and Z6116, similar to
> the more common 4116 DRAM.
>
Yep ... they were an oddity all right.  I don't remember using them, but the
number certainly does ring a bell, as an oddity, of course.  It wasn't unusual
to look at such oddities as opportunity to save some dough on components,
since they often became "distress" merchandise on the surplus market.
>
> Pete Peter Turnbull
> Network Manager
> University of York
>
>