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Replacement for Fluke 700013 IC (quad SPST analog switch)
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JoergR:
So the boards on my vertical layout that I had posted previously came and lo and behold - the worked perfectly - except that I mixuped up the order of the output switches  :palm: .... So I've removed that post from the thread and fortunately only one person had downloaded it... Sorry for that  :-[. Back to the drawing board and inspired by the horizontal setup posted above, I made another layout with correct switches this time. The boards came a couple of days ago. I've put sockets on the main PCB this way the daughterboards are raised high enough to be clear of all other parts. With U301-303 replaced all self tests passed!  :phew: DC voltage and current appear to work fine. Only in the low AC current range around 1mA there is a larger error - but I guess that can be fixed with calibration as I had previously erased all calibration values. I've used the DG411 and the 74AC logic chips. Only the Ohms circuit still gives me trouble. It only measures correctly on the 20k range and outputs the correct current of 1mA. So I suppose I also have to replace the remaining two 700013 ... I need to order the DG211 first, though.

If someone is still in need of replacements - I have a few PCBs to spare.

Thanks a lot again for the help I got here!
richipedia:
That mechanical design looks very nice. Good combination of THT and SMD parts to use space efficiently!
JoergR:
In hindsight, and looking at the pictures now, I feel that the switch chip should be moved over a bit to the edge of the board. The header pins don't need to be below the center of the chip. That would give the capacitors a bit more space. Oh well, ... I'm attaching the KiCad Files if someone still needs those.
I got the DG212 chips today and combined them with 74AC08 AND gates and now the meter is all up and running again.  :-DMM
That's the nice thing about richipedia's design, one can choose different chip combinations DGX12 + 08 AND or DGX11 + 00 NAND on the same board.
Kjo:
I spent a good deal of time during COVID working on the same concept and reported progress at the Fluke list over at groups.io.
I started by trying to use a PIC16F15323 to control a DG212B. It has 4 CLBs that can implement registered logic independent of the
instruction counter. Fluke timing for the 700013 is not that critical, but it wouldnt work in all 700013 positions. |O
I also tried 2 versions using 4000 series and 74HC series. Still had some issues. >:D Finally I landed on a 2-chip solution with a PLD & DG212B.
That version worked flawlessly and is only 40% bigger than the 700013 IC itself. :-+ Assembly is all SMD in SOIC packages & 4 0603 capacitors.
I put together a kit for the MK5 version for $18.95.
https://www.hollywoodcontrols.com/phpFluke/HC700013P.php

I also have a Z8611 clone I am looking at kiting. Similar to others out there. Based on U8840M.

You can also find pretty much all the ROMs that are in the wild there too.

kjo - KO3Y

Noopy:


TiN had sent me an ADG444B. I have thought about posting it in my "normal" Die-Thread but since you are talking a lot about analog switches (DG211) I will post the ADG444 here.




The die is 1,9mm x 1,7mm. You can easily spot the four switches.




The datasheet describes a ADG444A which is fabricated with an buried oxide layer to isolate the integrated transistors. The isolation prevents latch-up but probably also reduces leakage and crosstalk.




The die doesn´t look like to have this isolation layer.
In the OPA627 (https://www.richis-lab.de/Opamp22.htm) we have seen that it is possible to see an isolation layer at the side of a die.
But this is the B-version of the ADG444. No isolation to be expected.




A 1993 design.




Internal naming?




We see six mask revisions.
Nice big transistors.




Etch marker or mask alignment help.




Now that is a nice pin 1 marker!  8)




Here we see one switch built with two big transistors (PMOS and NMOS).




That is interesting:
The bulk of the upper transistor T1 is connected to Vdd. That is probably the PMOS. It´s switched with Ga.
The lower transistor T2 has to be the NMOS. It´s switched with Gb. It´s bulk is connected to Vss by a third transistor switched with Ga (NMOS). So the Vss for better isolation is only connected to T2 in the off state.
At the lower end of T2 you see the metal layer connecting the channel with the bulk. In on state the channel is conducting connecting source and bulk. The higher bulk potential gives you a lower on resistance.  :-+




ADG441 and ADG442 have an internal voltage regulator for the logic supply. That is probably the circuit in the middle of the die. In the ADG444 it´s just connected to Vdd and GND. With a small metal layer change you can connect Vl.  :-+


https://www.richis-lab.de/aswitch02.htm

 :-/O
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