[Libre-silicon-devel] sea of gates and open analog

Éger Ferenc eegerferenc at gmail.com
Fri Feb 8 22:27:26 CET 2019

Hello All,

Just some thoughts on the topic:

- The architecture of Lattice PAC is very purpose-specific, tailored for
control-loop, monitoring and power management tasks. It is in no way a
general-purpose analog platform.

- Triad VCA is a better approach on the technical side. However, it has its
own drawbacks:
1. It is explicitly stated that the platform is patented, so using it
easily results in vendor lock-in with a single source.
2. They seem to use "usual" fabs behind the set and don't seem to be
interested in the "custom IC in single quantities for realistic end-user
price" business (as free software can be recompiled by the user, free Si
shall be re-tape-out-able by the end user)
3. The concerns mentioned by David also hold (hidden circuitry in pads, ...)

- If a IC project exists that is analog and open-source and useful
simultaneously: I don't think so. Analog designs are inseparable from the
PDK and technology they were made for: a design made for an university or
research process lacks the manufacturing capability that would be needed to
be used for real-life volumes, while a design tainted by the PDK of a
commercial process would be born secret (if everyone knows that
R=Rsq*(L/W), and Rsq is secret, then any R,W,L triplets for that Rsq would
also be secret).


On Wed, Feb 6, 2019 at 8:28 AM ludwig jaffe <ludwig.jaffe at gmail.com> wrote:

> Hi all,
> also lattice has programable analog which is an ic containing opamps,
> switched capacitor filters bandgap references and some analog muxes which
> are transfer gates I guess, and some programable resistors (mux and
> resistor on chip) and capacitors.
> They are called PAC, iirc.
> Just look it up.
> If we want such we can start with a bandgap some op amps like lm324 and a
> lot of transfer gates like cd4066.
> With a lot of pins we can connect external components and we may have on
> chip resistors and  matched pair transistors
> in bipolar and junction fets .
> Cheers
> Ludwig
> On Tuesday, February 5, 2019, Staf Verhaegen <staf at fibraservi.eu> wrote:
> > Luke Kenneth Casson Leighton schreef op di 05-02-2019 om 07:34 [+0000]:
> >
> > On Tuesday, February 5, 2019, Luke Kenneth Casson Leighton <
> lkcl at lkcl.net> wrote:
> >
> > Hi best place to ask,
> > Have forgotten the name of a company that has a sea of gates high end
> ASIC, you get to do only the one mask, the via layer. Does anyone know the
> company? It is apparently supported by libre design tools.
> >
> >
> > So sorry, um I found it:
> https://www.easic.com/products/28-nm-easic-nextreme-3/
> >
> > They are now Intel and not interested in low to medium volume.
> >
> > Second, somewhere in this talk https://youtu.be/zXwy65d_tu8 is
> mentioned an open analog design project, does anyone know what that project
> is?
> >
> > Haven't found this one yet
> >
> > The VIA programmable analog company I know of is Triad Semiconductor
> with their configurable IC Technology.
> > greets,
> > Staf.
> >
> --
> Send from mobile phone with autocorrection / autofill. Blame my phone for
> typos.
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