12 Dec
2010
12 Dec
'10
12:05 p.m.
Brent wrote:
On 2010 Dec 10, at 2:36 AM, Christian Corti wrote:
>
> we've had a look inside our IME 122 calculator and discovered that it
> is full of SN14xx logic ICs. They are mainly from TI, but there are
> also some from Motorola and others. It seems that they have the same
> function and pinout as the SN74xx parts but there must be a difference
> since the machine has quite a lot of SN1401 (the SN7401 is a quad
> open-collector NAND), but there are no pullup resistors anywhere!
> Some of the types are SN1400, SN1401, SN1474, SN1490; the ALU is made
> up
> of SN1482 and SN1483.
> Anyone knows this series? BTW the supply voltage is 5V.
I can't find a reference for those numbers, and I
haven't seen them
before, however I have seen TI inexplicably producing series identical
or similar to more-common series, but numbered differently. For
example, the SN3900 and SN4500 series are very similar to more-common
DTL series such as the 700/800/900 series, but I have never seen a
reference for the 3900 or 4500 series in TI databooks. One suggestion
might be they were a 'consumer-grade' series, a step below the standard
commercial-grade stuff.
Remember this was the late 60's or early 70's, and the thought of 7400 as the
"super series" with variants like 74L00, 74H00, 74S00 actually being inside the
family had not quite taken over in the same sense that it did later,
even inside TI. I don't think it's so much that the
SN1400's/SN3900's/SN4500's
were a step below commercial grade, but they probably had product-specific
fanin/fanout/noise/current constraints and maybe even custom pinouts
or built-in pullup variants in their specs.
The 7400 "super series" of pin compatible parts in different
speed/current/fanout
levels organized by 74L00, 74H00, 74S00, 74LS00 with often identical pinouts
was truly genius from a marketing-meets-technology point of view.
Not too different than say the 9-pin dual triode with similar to
identical pinouts but different gain variants (e.g. 12AU7/12AT7/12AX7) and a zillion
commercial/aerospace/computer variants (e.g. 5814A, 5963, etc.)
With regards to pinouts not everyone even inside a company had the same thoughts
regarding pin locations for Vcc and gnd. TI did a pretty good job most of the time
putting
them at 7 and 14 or 8 and 16 for TTL which did simplify layout, but there are lots of
exceptions
even inside the TTL product space. And sometimes there were good reasons for the
exceptions, other times I think it was just internal squabbling :-)
You can see some of this playing out in TI's competitors logic families too, e.g.
Signetics
Utilogic with different subfamilies inside the Utilogic superfamily.
Tim.
12 Dec
12 Dec
12:29 p.m.
On 12 Dec 2010 at 15:05, Shoppa, Tim wrote:
With regards to pinouts not everyone even inside a
company had the
same thoughts regarding pin locations for Vcc and gnd. TI did a pretty
good job most of the time putting them at 7 and 14 or 8 and 16 for TTL
which did simplify layout, but there are lots of exceptions even
inside the TTL product space. And sometimes there were good reasons
for the exceptions, other times I think it was just internal
squabbling :-)
...and sometimes differing between sub-families with the same numeric
part number. (e.g. 7486 vs. 74L86).
The idea of which way the gates in package should point also seems to
be an early bone of contention (7400 vs. 7401).
And even the issue of pairing inputs with outputs or placing inputs
on the opposite side of the package for bus-related chips (e.g.
74LS373 vs. 74LS573).
--Chuck
13 Dec
13 Dec
10:59 a.m.
On 2010 Dec 12, at 12:05 PM, Shoppa, Tim wrote:
Brent wrote:
On 2010 Dec 10, at 2:36 AM, Christian Corti
wrote:
>
> we've had a look inside our IME 122 calculator and discovered that
> it
> is full of SN14xx logic ICs. They are mainly from TI, but there are
> also some from Motorola and others. It seems that they have the same
> function and pinout as the SN74xx parts but there must be a
> difference
> since the machine has quite a lot of SN1401 (the SN7401 is a quad
> open-collector NAND), but there are no pullup resistors anywhere!
> Some of the types are SN1400, SN1401, SN1474, SN1490; the ALU is
> made
> up
> of SN1482 and SN1483.
> Anyone knows this series? BTW the supply voltage is 5V.
I can't find a reference for those numbers,
and I haven't seen them
before, however I have seen TI inexplicably producing series identical
or similar to more-common series, but numbered differently. For
example, the SN3900 and SN4500 series are very similar to more-common
DTL series such as the 700/800/900 series, but I have never seen a
reference for the 3900 or 4500 series in TI databooks. One suggestion
might be they were a 'consumer-grade' series, a step below the
standard
commercial-grade stuff.
Remember this was the late 60's or early 70's, and the thought of 7400
as the
"super series" with variants like 74L00, 74H00, 74S00 actually being
inside the
family had not quite taken over in the same sense that it did later,
even inside TI. I don't think it's so much that the
SN1400's/SN3900's/SN4500's
were a step below commercial grade, but they probably had
product-specific
fanin/fanout/noise/current constraints and maybe even custom pinouts
or built-in pullup variants in their specs. The 7400 "super series" of pin compatible
parts in different
speed/current/fanout
levels organized by 74L00, 74H00, 74S00, 74LS00 with often identical
pinouts
was truly genius from a marketing-meets-technology point of view.
Not too different than say the 9-pin dual triode with similar to
identical pinouts but different gain variants (e.g. 12AU7/12AT7/12AX7)
and a zillion
commercial/aerospace/computer variants (e.g. 5814A, 5963, etc.)
Regarding the SN1400 series though, the 74H and 74L variants are
present in the 1969 TI TTL databook, a little before or around the same
time as the noted SN1400 units. There were lots of other TTL series
being produced by other manufacturers, but the SN1400 one seems odd
coming from TI, who had established the 7400 series years earlier, and
the application in a calculator would or could be adequately covered by
the standard series.
Grading was just one line of speculation, certainly there is the
potential of other possibilities as you suggest. I find it interesting
to investigate the lesser-known IC series from the early days of ICs.
For technically purposes we can generally come to an adequate
explanation for the sake of maintenance of old equipment that uses
them, it would nonetheless be interesting to see original data to
explain just what TI or others were doing and why and how they differ
from the more-common series. Detailed information about
even the common
DTL series can be rare to come by, IME.
Just to see if anything recent was out there, I went looking on the web
for other references to the SN3900 series and found three sites: one in
another calculator examination, and two sites that were simply ripping
off (without source ref or attribution) the information presented on my
own web site.
With regards to pinouts not everyone even inside a
company had the
same thoughts
regarding pin locations for Vcc and gnd. TI did a pretty good job most
of the time putting
them at 7 and 14 or 8 and 16 for TTL which did simplify layout, but
there are lots of exceptions
even inside the TTL product space. And sometimes there were good
reasons for the
exceptions, other times I think it was just internal squabbling :-)
The 7490 was one that always bugged me, very common and one of the
first 2 or 3 IC types I ever used (pins 5/Vcc and 10/GND).
One of the oddest I've seen (relative to conventional standards) is a
small logic series produced by Sony, with power on pins 13 and 14.
(Also worth mentioning v.v. the original discussion, as it seems to
have open-collector outputs, with no pull-ups in use.
http://www.cs.ubc.ca/~hilpert/eec/ics/Sony500.html )
You can see some of this playing out in TI's
competitors logic
families too, e.g. Signetics
Utilogic with different subfamilies inside the Utilogic superfamily.
14 Dec
14 Dec
2:41 a.m.
On Mon, 13 Dec 2010, Brent Hilpert wrote:
Historically, the first SN TTL-ICs had their supply pins in the middle
because they used flat-packs (one would call them SMD today) and not DIPs
which were used later. The SN54xx series was an evolution from the
three-digit series (SN54x), i.e. an SN5400 was like an SN540 but in a
bigger package (something like four instead of three NANDs), and so on.
Christian
Regarding the SN1400 series though, the 74H and 74L
variants are present in
the 1969 TI TTL databook, a little before or around the same time as the
noted SN1400 units. There were lots of other TTL series being produced by
other manufacturers, but the SN1400 one seems odd coming from TI, who had
established the 7400 series years earlier, and the application in a
calculator would or could be adequately covered by the standard series.
Yeah, and I think that it doesn't make sense to have several manufacturers
produce (i.e. TI, Motorola, PH (whatever they are, at least neither
Philips nor Siemens)) a specialized series derived from the 54xx/74xx just
for some calculators. Maybe they used rejects from production and labelled
them differently, or maybe they used hand-picked examples.
Just to see if anything recent was out there, I went
looking on the web for
other references to the SN3900 series and found three sites: one in another
The Canon Canola 1210 for example uses the SN3900 and SN4500 series, IIRC.
And they don't look like TTL at all. I think that I have some pictures
from that machine.
them at 7 and
14 or 8 and 16 for TTL which did simplify layout, but there
are lots of exceptions
even inside the TTL product space. And sometimes there were good reasons
for the
exceptions, other times I think it was just internal squabbling :-)
The 7490 was one that always bugged me, very common and one of the first 2 or
3 IC types I ever used (pins 5/Vcc and 10/GND).
11:11 a.m.
On 2010 Dec 14, at 2:41 AM, Christian Corti wrote:
Historically, the first SN TTL-ICs had their supply pins in the middle
because they used flat-packs (one would call them SMD today) and not
DIPs which were used later. The SN54xx series was an evolution from
the three-digit series (SN54x), i.e. an SN5400 was like an SN540 but
in a bigger package (something like four instead of three NANDs), and
so on.
We've had this discussion before. TI's earliest RTL/DTL series were
3-digit (e.g. SN53x, SN51x), but I have never seen evidence that the
5400/7400 series began as 540/740. TI docs I have indicate the series
began as 4-digit SN54xx. They were in 14-pin flat-paks, but as you say
with power on the center pins, and very different pinouts from the
later DIPs.
Fairchild claimed to have developed the DIP, most of their early
TTL/DTL stuff had power on the corner pins (there are exceptions, and
some of their other series such as CTL used other pins). It may be that
TI adopted the Fairchild pinouts when TI moved to DIPs.
(The weird thing about the 7490 is power is on neither the corner pins
(7,14) nor the center pins (4,11).
On Mon, 13 Dec 2010, Brent Hilpert wrote:
The 3900, 4500 are definitely DTL. I did obtain a single page
containing pinouts and internal schematic for 3900/4500 ICs with one
calculator that uses them. I just mentioned those series as another
example of TI producing 'oddball' series.
Regarding the SN1400 series though, the 74H and
74L variants are
present in the 1969 TI TTL databook, a little before or around the
same time as the noted SN1400 units. There were lots of other TTL
series being produced by other manufacturers, but the SN1400 one
seems odd coming from TI, who had established the 7400 series years
earlier, and the application in a calculator would or could be
adequately covered by the standard series.
Yeah, and I think that it doesn't make sense to have several
manufacturers produce (i.e. TI, Motorola, PH (whatever they are, at
least neither Philips nor Siemens)) a specialized series derived from
the 54xx/74xx just for some calculators. Maybe they used rejects from
production and labelled them differently, or maybe they used
hand-picked examples.
Just to see if anything recent was out there, I
went looking on the
web for other references to the SN3900 series and found three sites:
one in another
The Canon Canola 1210 for example uses the SN3900 and SN4500 series,
IIRC. And they don't look like TTL at all. I think that I have some
pictures from that machine. them at 7 and 14 or 8 and 16 for TTL which did
simplify layout, but
there are lots of exceptions
even inside the TTL product space. And sometimes there were good
reasons for the
exceptions, other times I think it was just internal squabbling :-)
The 7490 was one that always bugged me, very common and one of the
first 2 or 3 IC types I ever used (pins 5/Vcc and 10/GND).
11:28 a.m.
On 14 Dec 2010 at 11:11, Brent Hilpert wrote:
Fairchild claimed to have developed the DIP, most of
their early
TTL/DTL stuff had power on the corner pins (there are exceptions, and
some of their other series such as CTL used other pins). It may be
that TI adopted the Fairchild pinouts when TI moved to DIPs.
(The weird thing about the 7490 is power is on neither the corner pins
(7,14) nor the center pins (4,11).
Motorola used power pins as 4 and 10 on their 14-pin DIPs for the
MTTL I and II series.MTTL III changed that to 7 and 14 (corners).
MRTL in plastic DIL appeared to used 4 and 11.
--Chuck
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cc＠informatik.uni-stuttgart.de -
cclist＠sydex.com -
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tshoppa＠wmata.com