[Libre-silicon-devel] Analog Try-out "triple-5"

ludwig jaffe ludwig.jaffe at gmail.com
Mon Mar 4 05:10:17 CET 2019

Hi Hagen,
we could make a combo chip:
NE555, some LM741, and some CD4066 (transfer gate)
UC3845, UC3843 (simple PWM chip for switch mode power supply)
So geeks could combine the chips using transfer gates :-)

Or lets think about a simple analog geeky chip, that contains:
saw tooth generator, comparator, rs latch, error-amps (UC3845)
while the the saw tooth generator is replaced with a NE555 (transfer gate,
or just fitting the ne 555 instead of the internal uc3845 saw tooth
The Op-Amp in the UC3845 may be replaced with a 741 or similar simple op

So we have an universal circuit containing:
-OPAMPS (741, LM324 or similar)
-universal SAWTOOTH-Generators (NE555)
-RS-Latch (NE555 also has a latch) for use in fake UC3845
-the rest used in UC3845

the transfer gates are used as pin mux so we can access internal stuff
of the modified UC3845 and split it into, OP-AMPS, NE555 and so on.

So having a programable simple analog circuit would be cool.
Also a TL431 programable z-diode woud be cool as well as
TAA 761 open collector op-amp.
So here we could combine TL431 with TAA761 open collector
op amp.

We would have an analog "fpga"

What do you think?



On Sun, Mar 3, 2019 at 2:13 PM Hagen SANKOWSKI <hsank at posteo.de> wrote:

> Hello List.
> Today in our weekly Mumble Session we talked about a smaller chip, which
> could be realized before the Northpoint.
> The Reason is mostly, that the Northpoint (as an small MCU) - beside the
> Standard Cells - also has some challenging Analog Stuff (like the ADC,
> Pad-Cells) which set the hurdle a little bit high.
> We need some physical haptic fancy / shiny silicon before which gives us
> also a realistic way to verify our simulation after model measurement we
> do with PearlRiver. Something we could hand over to other people and
> which blinks..
> Well, we came across the well-known "triple-5 chip". The original NE555
> [0] was developed by the Swiss electronics engineer Hans Camenzind [1]
> and get cloned by nearly all silicon firms on the market in this era.
> Great starting points for our CMOS-based clone are the wikipedia site
> and the free eBook [2] of the original author. I strongly recommend
> everybody to read this great book!
> Mostly the 555 chips are in the -55 to +125 C temperature range - the
> same we assume for our technology. And the voltage supply goes up to +18
> Volt, I already saw 555 which worked with higher voltage. If we like, we
> could using our BiCMOS feature for the output driver - driving the same
> current with less power consumption.
> The 555 chip has a legendary status between electronic engineers, radio
> amateurs and tinkers. And some of them writing obeisance on hackaday.com
> still in 2018 [3]. Many variations of the chip are still in production.
> Short - the 555 would be a great try-out for LibreSilicon! And I am
> proud to announce that Ferenc will be our Lead for the "LS 555"
> (LibreSilicon triple-5). Thanks Ferenc for your commitment!
> Regards,
> Hagen.
> [0] https://en.wikipedia.org/wiki/555_timer_IC
> [1] https://en.wikipedia.org/wiki/Hans_Camenzind
> [2] http://www.designinganalogchips.com/
> [3] https://hackaday.com/2018/10/10/the-555-and-how-it-got-that-way/
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> Libre-silicon-devel at list.libresilicon.com
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