I'm looking for the smallest unreasonably possible way of building a
small circuit.
The following "spec" is too vague and broad to allow a certain answer
but people may well have ideas based on the following.
I haven't looked yet at the raw silicon size  limitations - which it
will probably come down to.
eg how large is a raw 10F204?


The devices job is to look at the output of two VERY small coils and
report what it sees by means TBD. Various ideas occur but best
solution yet unknown.
It's doable, but a challenge.
The "other part", not mentioned here, is as challenging :-)

Probably 1 IC - just maybe discretes only.
If an IC it may be a microcontroller.

Desired outer dimensions of complete assembled circuit are say 2mm x  < 2mm=
 .
Slightly more than 2mm in one dimension MAY be acceptable.
Thickness ideally around 1mm. 1.5mm max.
ie really wants to slide inside a thin wall 2mm OD tube. MAY be able
to be 2mm abs max.

To fit a rectangle of width w and height h inside a circle of diameter d th=
en

             w <=3D sqrt (d^2 - h^2)
and
             h <=3D sqrt (d^2 - w^2)

eg for d =3D 2mm, h=3D1mm

    w <=3D sqrt(2^2 - 1^2) =3D~ 1.7mm

etc
______________


No battery.

Smallest packages off the shelf look too large.
Presumably something like COB and an ASIC may be in order.

As an indication:

PIC10F204 comes in 8-VFDFN exposed pads =3D

            2mm x 3mm x 0.8mm tall nominal (1 mm max)

Oddly, by taking careful and allowable liberties with the SOT23-6
version you could reduce the overall size - say

          1.8 x 2.7 x 1  - which just doesn't fit in a 2mm circle.
A bit more massaging and it would. 1.55 is the im[possible to meet
lower minimum typical width.


Max 9610, LiIon battery precision current sense amp.
Micro DFN6. http://datasheets.maxim-ic.com/en/ds/MAX9610.pdf

           1.45 mm x 0.95 mm x 0.8 max tall


Diodes Inc AP7021 LDO
DFN2018-6 (USP 6B)
2 x 1.8 x 0.6


Thoughts?



    R
--=20
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