Utilogic II (was these RTL or what?)

Brent Hilpert hilpert at cs.ubc.ca
Tue Oct 2 14:37:08 CDT 2007

"Roy J. Tellason" wrote:
> On Tuesday 02 October 2007 04:38, Al Kossow wrote:
> > >> I ran across some data in the pile of what I've been collecting, and
> > >> there's some stuff there apparently by Signetics (?) referring to what
> > >> they're calling "Utilogic II" -- is this stuff RTL or what?  It doesn't
> > >> say.  Dates are in the late 1960s,  and it looks like it,  but I figured
> > >> I'd ask in here...
> >  >
> >  > Goggle finds only a few hits for utilogic,and is mostly a odd chip for
> >  > sale.
> >
> >  > I suspect more TTL rather than DTL. Ben.
> >
> > look under http://bitsavers.org/pdf/signetics/_dataBooks/
> I don't recall where I picked them up,  but what I am referring to is indeed a
> couple of databooks...  I might have gotten them there,  even.  Maybe I just
> need to dig into them further.

"UtilLogicII_Handbook_1968.pdf" from Al's bitsavers presents some internal schematics.
Kind of interesting in that the family is a mixture of technologies: AND gate
inputs are current-*sinking* multi-emitter TTL style, N/OR gates inputs are
current-*sourcing* like RTL with a common limiting resistor but referred to in
the text as DTL with the diodes replaced with transistors. N/OR outputs are
totem-pole so they'll both source and sink current. AND gate outputs only have
a high-side transistor so they'll only source. If one stuck to AND-OR-NOT
combinatorics it was probably OK to design with.

I came across a small pile of unknown 60s-era SSI gold-ceramic ICs recently
(SG 2xx series) and popped the lid off one just for fun to see if I could
figure out what it was under a microscope (looks like a dual 4-input TTL or
DTL gate), then later found some mention of them in the cross-refs of an early
TI TTL databook.

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