SPICE help, please

"Equipment Smarter Than Operator" ;-) ...Jim Thompson

--
| James E.Thompson, CTO                            |    mens     |
| Analog Innovations, Inc.                         |     et      |
| Analog/Mixed-Signal ASIC's and Discrete Systems  |    manus    |
| Phoenix, Arizona  85048    Skype: Contacts Only  |             |
| Voice:(480)460-2350  Fax: Available upon request |  Brass Rat  |
| E-mail Icon at http://www.analog-innovations.com |    1962     |
             
I love to cook with wine.     Sometimes I even put it in the food.

Puts those nodes into the "select list". Doesn't automatically display, as in PSpice. ...Jim Thompson

--
| James E.Thompson, CTO                            |    mens     |
| Analog Innovations, Inc.                         |     et      |
| Analog/Mixed-Signal ASIC's and Discrete Systems  |    manus    |
| Phoenix, Arizona  85048    Skype: Contacts Only  |             |
| Voice:(480)460-2350  Fax: Available upon request |  Brass Rat  |
| E-mail Icon at http://www.analog-innovations.com |    1962     |
             
I love to cook with wine.     Sometimes I even put it in the food.

• U0101, U0102, U0104, U0105, U0201, U0202, U0204, U0205, U0401, U0402, U0404, U0405, U0501, U0502, U0504, and U0505 all draw about +44pA when I1 is set to 2.0nA. Likewise, U0103, U0203, U0403, U0503, U0301, U0302, U0304, and U0305 all draw about -177pA with the same drive. The net total "bypassing" of U0303 is -712pA and the current thru U0303 is about -1.3nA; adding those together gives about -2.0nA; the total I1 drive SO all is accounted for. Isn't it nice that 1+1=2?

• So, pick one of the parts in the +44pA set; what is the current path? Likewise, pick one of the parts in the -177pA set; what is the current path?

• See the subckt model which is 2 diodes back to back clearly labeled and specified as to voltage. An equivalent might be a transistor with a floating base (node 3 in the subcircuit).

• Yes; sorry about that, i had no idea that the Codatron(TM) part schematic would be so large; that was added last. And the "editing" capabilities leave a lot to be desired for separating things.

• Yep; i put them in first, then i put in the "grid" lines.

Thanks. Google did not give that on the first page. In this case, JTSTG.

So, which, out of subckt nodes 1 and 2, is C, and which E?

You have to watch for crossed wires spontaneously connecting, when dragging.

LTSpice runs fine without them. Faster,too.

Still working on it ;-)

--
"For a successful technology, reality must take precedence 
over public relations, for nature cannot be fooled."
                                       (Richard Feynman)

Aha! Undocumented feature.

More or less like an LTSpice .SAVE card.

--
"For a successful technology, reality must take precedence 
over public relations, for nature cannot be fooled."
                                       (Richard Feynman)

I've done a bit of work, redrawn a symbol that's more compact, and redrawn the matrix to reflect matrix numbering conventions - (X row column).

To make it simpler, I ditched the current source in favor of a voltage source with series R, then did an op point analysis, schematic attached.

There are sneak circuits from row 3 and column 3, apparently due to "unused" elements leaking, but not enough to worry about at this stage Worst case 1.7nA, whilst we have 500 microamps in the DUT. 430pA in more remote devices.

I think it's time to make a better device model, incorporating temp coefficients, and real leakage figures. The Berkeley Spice diode models probably don't adequately reflect the real thing.

*codatron2.asy - goes in /lib/sym/special functions. Version 4 SymbolType CELL LINE Normal -8 18 22 -2 LINE Normal 22 -2 23 30 LINE Normal -8 18 23 30 LINE Normal 0 0 6 8 LINE Normal 25 51 42 36 LINE Normal 25 51 25 51 LINE Normal 23 30 25 51 LINE Normal 42 36 23 30 LINE Normal 49 64 34 43 WINDOW 0 24 -14 Left 2 SYMATTR Prefix X SYMATTR Description Proprietary shunt regulator SYMATTR Value Codatron PIN 0 0 NONE 0 PINATTR PinName + PINATTR SpiceOrder 1 PIN 48 64 NONE 0 PINATTR PinName - PINATTR SpiceOrder 2 ********************

Version 4 SHEET 1 1164 1088 WIRE 128 32 -48 32 WIRE 272 32 128 32 WIRE 432 32 272 32 WIRE 576 32 432 32 WIRE -16 64 -48 32 WIRE 144 64 128 32 WIRE 288 64 272 32 WIRE 448 64 432 32 WIRE 608 64 576 32 WIRE 64 176 32 128 WIRE 224 176 192 128 WIRE 368 176 336 128 WIRE 528 176 496 128 WIRE 688 176 656 128 WIRE 128 208 -48 208 WIRE 288 208 128 208 WIRE 416 208 288 208 WIRE 576 208 416 208 WIRE -32 240 -48 208 WIRE 144 240 128 208 WIRE 304 240 288 208 WIRE 432 240 416 208 WIRE 592 240 576 208 WIRE 368 336 368 176 WIRE 368 336 352 304 WIRE 64 352 64 176 WIRE 64 352 16 304 WIRE 224 352 224 176 WIRE 224 352 192 304 WIRE 528 368 528 176 WIRE 528 368 480 304 WIRE 688 368 688 176 WIRE 688 368 640 304 WIRE -48 400 -320 400 WIRE 128 400 -48 400 WIRE 272 400 128 400 WIRE 416 400 272 400 WIRE 576 400 416 400 WIRE -32 432 -48 400 WIRE 144 432 128 400 WIRE 288 432 272 400 WIRE 432 432 416 400 WIRE 592 432 576 400 WIRE 64 544 64 352 WIRE 64 544 16 496 WIRE 224 544 224 352 WIRE 224 544 192 496 WIRE 368 544 368 336 WIRE 368 544 336 496 WIRE 528 560 528 368 WIRE 528 560 480 496 WIRE 688 560 688 368 WIRE 688 560 640 496 WIRE 144 592 -48 592 WIRE 288 592 144 592 WIRE 432 592 288 592 WIRE 592 592 432 592 WIRE -32 624 -48 592 WIRE 160 624 144 592 WIRE 304 624 288 592 WIRE 448 624 432 592 WIRE 608 624 592 592 WIRE -320 640 -320 400 WIRE 224 704 224 544 WIRE 224 704 208 688 WIRE 368 720 368 544 WIRE 368 720 352 688 WIRE 64 736 64 544 WIRE 64 736 16 688 WIRE 528 736 528 560 WIRE 528 736 496 688 WIRE 688 736 688 560 WIRE 688 736 656 688 WIRE 144 784 -48 784 WIRE 288 784 144 784 WIRE 432 784 288 784 WIRE 592 784 432 784 WIRE -320 816 -320 720 WIRE -32 816 -48 784 WIRE 160 816 144 784 WIRE 304 816 288 784 WIRE 448 816 432 784 WIRE 608 816 592 784 WIRE 64 944 64 736 WIRE 64 944 16 880 WIRE 224 944 224 704 WIRE 224 944 208 880 WIRE 368 944 368 720 WIRE 368 944 352 880 WIRE 528 944 528 736 WIRE 528 944 496 880 WIRE 688 944 688 736 WIRE 688 944 656 880 WIRE -320 992 -320 896 WIRE 368 992 368 944 WIRE 368 992 -320 992 WIRE -320 1072 -320 992 FLAG -48 32 R1 FLAG -48 208 R2 FLAG -48 400 R3 FLAG -48 592 R4 FLAG -48 784 R5 FLAG 64 944 C1 FLAG 224 944 C2 FLAG 368 944 C3 FLAG 528 944 C4 FLAG 688 944 C5 FLAG -320 1072 0 SYMBOL SpecialFunctions\\codatron2 -16 64 R0 SYMATTR InstName U11 SYMATTR Description Codatron SYMBOL SpecialFunctions\\codatron2 144 64 R0 SYMATTR InstName U12 SYMATTR Description Codatron SYMBOL SpecialFunctions\\codatron2 288 64 R0 SYMATTR InstName U13 SYMATTR Description Codatron SYMBOL SpecialFunctions\\codatron2 448 64 R0 SYMATTR InstName U14 SYMATTR Description Codatron SYMBOL SpecialFunctions\\codatron2 608 64 R0 SYMATTR InstName U15 SYMATTR Description Codatron SYMBOL SpecialFunctions\\codatron2 -32 240 R0 SYMATTR InstName U21 SYMATTR Description Codatron SYMBOL SpecialFunctions\\codatron2 144 240 R0 SYMATTR InstName U22 SYMATTR Description Codatron SYMBOL SpecialFunctions\\codatron2 304 240 R0 SYMATTR InstName U23 SYMATTR Description Codatron SYMBOL SpecialFunctions\\codatron2 432 240 R0 SYMATTR InstName U24 SYMATTR Description Codatron SYMBOL SpecialFunctions\\codatron2 592 240 R0 SYMATTR InstName U25 SYMATTR Description Codatron SYMBOL SpecialFunctions\\codatron2 -32 432 R0 SYMATTR InstName U31 SYMATTR Description Codatron SYMBOL SpecialFunctions\\codatron2 144 432 R0 SYMATTR InstName U32 SYMATTR Description Codatron SYMBOL SpecialFunctions\\codatron2 288 432 R0 SYMATTR InstName U33 SYMATTR Description Codatron SYMBOL SpecialFunctions\\codatron2 432 432 R0 SYMATTR InstName U34 SYMATTR Description Codatron SYMBOL SpecialFunctions\\codatron2 592 432 R0 SYMATTR InstName U35 SYMATTR Description Codatron SYMBOL SpecialFunctions\\codatron2 -32 624 R0 SYMATTR InstName U41 SYMATTR Description Codatron SYMBOL SpecialFunctions\\codatron2 160 624 R0 SYMATTR InstName U42 SYMATTR Description Codatron SYMBOL SpecialFunctions\\codatron2 304 624 R0 SYMATTR InstName U43 SYMATTR Description Codatron SYMBOL SpecialFunctions\\codatron2 448 624 R0 SYMATTR InstName U44 SYMATTR Description Codatron SYMBOL SpecialFunctions\\codatron2 608 624 R0 SYMATTR InstName U45 SYMATTR Description Codatron SYMBOL SpecialFunctions\\codatron2 -32 816 R0 SYMATTR InstName U51 SYMATTR Description Codatron SYMBOL SpecialFunctions\\codatron2 160 816 R0 SYMATTR InstName U52 SYMATTR Description Codatron SYMBOL SpecialFunctions\\codatron2 304 816 R0 SYMATTR InstName U53 SYMATTR Description Codatron SYMBOL SpecialFunctions\\codatron2 448 816 R0 SYMATTR InstName U54 SYMATTR Description Codatron SYMBOL SpecialFunctions\\codatron2 608 816 R0 SYMATTR InstName U55 SYMATTR Description Codatron SYMBOL voltage -320 800 R0 WINDOW 123 0 0 Left 2 WINDOW 39 0 0 Left 2 SYMATTR InstName V1 SYMATTR Value 4000 SYMBOL res -336 624 R0 SYMATTR InstName R1 SYMATTR Value 300k TEXT 712 16 Left 2 !.MODEL DMOD1 D (BV=398)\n.MODEL DMOD2 D (BV=3840)\n.SUBCKT Codatron 1 2 ; HT-400\n DZ1 1 3 DMOD1\n DZ2 2 3 DMOD2\n.ENDS Codatron TEXT 744 264 Left 2 !.op TEXT 728 320 Left 2 ;View Spice error log to see device voltages and currents

--
"For a successful technology, reality must take precedence 
over public relations, for nature cannot be fooled."
                                       (Richard Feynman)

• Tell me. I have re-drawn everything, including the Codatron(TM).

ALL re-done here,with some analysis.

• Array5x5.ASC: Version 4 SHEET 1 1564 808 WIRE -176 -480 -256 -480 WIRE -16 -480 -176 -480 WIRE 80 -480 -16 -480 WIRE 176 -480 80 -480 WIRE 272 -480 176 -480 WIRE 368 -480 272 -480 WIRE 656 -480 368 -480 WIRE -256 -448 -256 -480 WIRE -176 -368 -176 -480 WIRE -48 -368 -96 -368 WIRE 48 -368 -48 -368 WIRE 144 -368 48 -368 WIRE 240 -368 144 -368 WIRE 336 -368 240 -368 WIRE 656 -368 336 -368 WIRE -16 -336 -16 -400 WIRE 80 -336 80 -400 WIRE 176 -336 176 -400 WIRE 272 -336 272 -400 WIRE 368 -336 368 -400 WIRE -176 -272 -176 -368 WIRE -48 -272 -96 -272 WIRE 48 -272 -48 -272 WIRE 144 -272 48 -272 WIRE 240 -272 144 -272 WIRE 336 -272 240 -272 WIRE 656 -272 336 -272 WIRE -16 -240 -16 -336 WIRE 80 -240 80 -336 WIRE 176 -240 176 -336 WIRE 272 -240 272 -336 WIRE 368 -240 368 -336 WIRE -176 -176 -176 -272 WIRE -48 -176 -96 -176 WIRE 48 -176 -48 -176 WIRE 144 -176 48 -176 WIRE 240 -176 144 -176 WIRE 336 -176 240 -176 WIRE 528 -176 336 -176 WIRE 656 -176 528 -176 WIRE -16 -144 -16 -240 WIRE 80 -144 80 -240 WIRE 176 -144 176 -240 WIRE 272 -144 272 -240 WIRE 368 -144 368 -240 WIRE 528 -128 528 -176 WIRE 976 -128 528 -128 WIRE -176 -80 -176 -176 WIRE -48 -80 -96 -80 WIRE 48 -80 -48 -80 WIRE 144 -80 48 -80 WIRE 240 -80 144 -80 WIRE 336 -80 240 -80 WIRE 656 -80 336 -80 WIRE -16 -48 -16 -144 WIRE 80 -48 80 -144 WIRE 176 -48 176 -144 WIRE 272 -48 272 -144 WIRE 368 -48 368 -144 WIRE -176 16 -176 -80 WIRE -48 16 -96 16 WIRE 48 16 -48 16 WIRE 144 16 48 16 WIRE 240 16 144 16 WIRE 336 16 240 16 WIRE 656 16 336 16 WIRE -16 48 -16 -48 WIRE 80 48 80 -48 WIRE 176 48 176 -48 WIRE 272 48 272 -48 WIRE 368 48 368 -48 WIRE 976 272 976 -128 WIRE 976 432 976 352 WIRE 976 432 848 432 WIRE 1024 432 976 432 WIRE 848 448 848 432 WIRE 976 528 976 432 WIRE -176 560 -176 16 WIRE 176 608 176 48 WIRE 224 608 176 608 WIRE 736 608 688 608 WIRE 848 608 848 528 WIRE 848 608 816 608 WIRE 976 608 848 608 WIRE -16 688 -16 48 WIRE 80 688 80 48 WIRE 176 688 176 608 WIRE 272 688 272 48 WIRE 368 688 368 48 WIRE 848 688 848 608 WIRE 224 768 224 608 WIRE 688 768 688 608 WIRE 688 768 224 768 FLAG -256 -448 0 FLAG 80 688 102 FLAG 272 688 104 FLAG 368 688 105 FLAG 176 688 103 FLAG 848 688 0 FLAG -16 688 101 FLAG 1024 432 FRC FLAG 656 -368 201 FLAG 656 -272 202 FLAG 656 -176 203 FLAG 656 -80 204 FLAG 656 16 205 SYMBOL res -80 0 R90 WINDOW 0 0 56 VBottom 2 WINDOW 3 32 56 VTop 2 SYMATTR InstName R205 SYMATTR Value 10E20 SYMBOL res 64 -496 R0 SYMATTR InstName R102 SYMATTR Value 10E20 SYMBOL res 256 -496 R0 SYMATTR InstName R104 SYMATTR Value 10E20 SYMBOL res 352 -496 R0 SYMATTR InstName R105 SYMATTR Value 10E20 SYMBOL res 960 256 R0 SYMATTR InstName R99 SYMATTR Value 20K SYMBOL res -32 -496 R0 SYMATTR InstName R101 SYMATTR Value 10E20 SYMBOL current 976 528 R0 WINDOW 123 0 0 Left 2 WINDOW 39 0 0 Left 2 SYMATTR InstName I1 SYMATTR Value 0 SYMBOL res 832 432 R0 SYMATTR InstName R98 SYMATTR Value 10E20 SYMBOL res 160 -496 R0 SYMATTR InstName R103 SYMATTR Value 10E20 SYMBOL res 832 592 R90 WINDOW 0 0 56 VBottom 2 WINDOW 3 32 56 VTop 2 SYMATTR InstName R97 SYMATTR Value 1 SYMBOL Codatron -48 32 R0 WINDOW 0 26 43 Right 2 WINDOW 3 2 -29 Invisible 2 SYMATTR InstName U0501 SYMBOL Codatron 48 32 R0 WINDOW 0 27 42 Right 2 WINDOW 3 2 -29 Invisible 2 SYMATTR InstName U0502 SYMBOL Codatron 144 32 R0 WINDOW 0 24 39 Right 2 WINDOW 3 2 -29 Invisible 2 SYMATTR InstName U0503 SYMBOL Codatron 240 32 R0 WINDOW 0 26 42 Right 2 WINDOW 3 2 -29 Invisible 2 SYMATTR InstName U0504 SYMBOL Codatron 336 32 R0 WINDOW 0 24 44 Right 2 WINDOW 3 2 -29 Invisible 2 SYMATTR InstName U0505 SYMBOL res -80 -96 R90 WINDOW 0 0 56 VBottom 2 WINDOW 3 32 56 VTop 2 SYMATTR InstName R1 SYMATTR Value 10E20 SYMBOL Codatron -48 -64 R0 WINDOW 0 26 43 Right 2 WINDOW 3 2 -29 Invisible 2 SYMATTR InstName U0401 SYMBOL Codatron 48 -64 R0 WINDOW 0 27 42 Right 2 WINDOW 3 2 -29 Invisible 2 SYMATTR InstName U0402 SYMBOL Codatron 144 -64 R0 WINDOW 0 24 39 Right 2 WINDOW 3 2 -29 Invisible 2 SYMATTR InstName U0403 SYMBOL Codatron 240 -64 R0 WINDOW 0 26 42 Right 2 WINDOW 3 2 -29 Invisible 2 SYMATTR InstName U0404 SYMBOL Codatron 336 -64 R0 WINDOW 0 24 44 Right 2 WINDOW 3 2 -29 Invisible 2 SYMATTR InstName U0405 SYMBOL res -80 -192 R90 WINDOW 0 0 56 VBottom 2 WINDOW 3 32 56 VTop 2 SYMATTR InstName R2 SYMATTR Value 10E20 SYMBOL Codatron -48 -160 R0 WINDOW 0 26 43 Right 2 WINDOW 3 2 -29 Invisible 2 SYMATTR InstName U0301 SYMBOL Codatron 48 -160 R0 WINDOW 0 27 42 Right 2 WINDOW 3 2 -29 Invisible 2 SYMATTR InstName U0302 SYMBOL Codatron 144 -160 R0 WINDOW 0 24 39 Right 2 WINDOW 3 2 -29 Invisible 2 SYMATTR InstName U0303 SYMBOL Codatron 240 -160 R0 WINDOW 0 26 42 Right 2 WINDOW 3 2 -29 Invisible 2 SYMATTR InstName U0304 SYMBOL Codatron 336 -160 R0 WINDOW 0 24 44 Right 2 WINDOW 3 2 -29 Invisible 2 SYMATTR InstName U0305 SYMBOL res -80 -288 R90 WINDOW 0 0 56 VBottom 2 WINDOW 3 32 56 VTop 2 SYMATTR InstName R3 SYMATTR Value 10E20 SYMBOL Codatron -48 -256 R0 WINDOW 0 26 43 Right 2 WINDOW 3 2 -29 Invisible 2 SYMATTR InstName U0201 SYMBOL Codatron 48 -256 R0 WINDOW 0 27 42 Right 2 WINDOW 3 2 -29 Invisible 2 SYMATTR InstName U0202 SYMBOL Codatron 144 -256 R0 WINDOW 0 24 39 Right 2 WINDOW 3 2 -29 Invisible 2 SYMATTR InstName U0203 SYMBOL Codatron 240 -256 R0 WINDOW 0 26 42 Right 2 WINDOW 3 2 -29 Invisible 2 SYMATTR InstName U0204 SYMBOL Codatron 336 -256 R0 WINDOW 0 24 44 Right 2 WINDOW 3 2 -29 Invisible 2 SYMATTR InstName U0205 SYMBOL res -80 -384 R90 WINDOW 0 0 56 VBottom 2 WINDOW 3 32 56 VTop 2 SYMATTR InstName R4 SYMATTR Value 10E20 SYMBOL Codatron -48 -352 R0 WINDOW 0 26 43 Right 2 WINDOW 3 2 -29 Invisible 2 SYMATTR InstName U0101 SYMBOL Codatron 48 -352 R0 WINDOW 0 27 42 Right 2 WINDOW 3 2 -29 Invisible 2 SYMATTR InstName U0102 SYMBOL Codatron 144 -352 R0 WINDOW 0 24 39 Right 2 WINDOW 3 2 -29 Invisible 2 SYMATTR InstName U0103 SYMBOL Codatron 240 -352 R0 WINDOW 0 26 42 Right 2 WINDOW 3 2 -29 Invisible 2 SYMATTR InstName U0104 SYMBOL Codatron 336 -352 R0 WINDOW 0 24 44 Right 2 WINDOW 3 2 -29 Invisible 2 SYMATTR InstName U0105 TEXT -192 792 Left 2 !.dc I1 0 1.5n 0.1n TEXT 32 784 Left 2 !.option noopiter TEXT -552 -264 Left 2 !.MODEL DMOD1 D (BV=398)\n.MODEL DMOD2 D (BV=3840)\n.SUBCKT Codatron 1 2 ; HT-400\n DZ1 1 3 DMOD1\n DZ2 2 3 DMOD2\n.ENDS Codatron

• Codatron.ASY: Version 4 SymbolType CELL LINE Normal 0 -16 0 0 LINE Normal 0 0 0 0 LINE Normal 0 0 0 0 LINE Normal 12 -5 0 0 LINE Normal 12 4 12 -5 LINE Normal 0 0 12 4 LINE Normal 20 0 0 0 LINE Normal 17 12 22 16 LINE Normal 17 16 22 16 LINE Normal 17 20 22 16 LINE Normal 17 12 17 20 LINE Normal 18 8 20 0 LINE Normal 17 16 8 16 LINE Normal 32 16 22 16 LINE Normal 8 8 18 8 LINE Normal 8 16 8 8 WINDOW 0 -34 0 Right 2 WINDOW 3 2 -29 Right 2 SYMATTR Value Codatron SYMATTR Prefix X SYMATTR Description Bipolar NPN transistor, open base PIN 32 16 NONE 0 PINATTR PinName Cathode PINATTR SpiceOrder 2 PIN 0 -16 NONE 8 PINATTR PinName Anode PINATTR SpiceOrder 1

** Prelim analysis: Follow a "typical" path, line 103 ("ground), up thru U0203, left (line 202) then thru U0201, down the 101 line to and left thru U0301, up and to the right (line 203) to I1 source. Three other paths from U0203 are via U0202, U0204 and U0205. Those four currents eventually get combined online 203. Likewise, there are four currents via U0101, U0201, U0401 and U0501. There are 16 devices that have about 44pA going "backwards" subtracting from 8 devices that have about 177pA going "forwards" adding to the major (desired) current thru U0303.

That is as far as i am now; not too bad preliminary. The fun starts: 1) ways to decrease or prevent most if not all of those "sneak" current flows, and 2) see if there is a simple non-switching way to do that, especially at all temperatures up to 204C.

I don't think there *is* a way.

In view of the fact that, whichever device is chosen to test, the results are the same (try it), does it matter about currents in the offline devices that are better than four orders of magnitude below the DUT current? Your test point voltage will be the same for all devices, except bad ones. I'd say the method is proved.

Why the current source, rather than a voltage source? Voltage sources are easier to implement.

The 10e20 resistors aren't necessary. the simulation will run without.

an .op analysis will show where all the currents are, and their relative magnitudes in one stroke.

Are you sure that the device model accurately represents the behavior of a real device? It's relying heavily on the default parameters of the Berkeley Spice diode model (there are two possible diode device models in LTSpice), see the manual.

If you want to do temperature sweeps, you need some temperature parameters in the device model, they are set at zero, unless you specify.

Here's what I get from my .op analysis, using a 4000V 300K source, the DUT is U33 (d:u33:z1 and d:u33:z2).

The matrix goes as:

11 12 13 14 15 21 22 23 24 25 31 32 33 34 35 41 42 43 44 45 51 52 53 54 55

Circuit: * H:\Spice\Codatron_matrix.asc

Direct Newton iteration for .op point succeeded. Semiconductor Device Operating Points: --- Diodes --- Name: d:u55:z2 d:u54:z2 d:u53:z2 d:u52:z2 d:u51:z2 Model: dmod2 dmod2 dmod2 dmod2 dmod2 Id: 4.30e-10 4.30e-10 -1.72e-09 4.30e-10 4.30e-10 Vd: 2.76e-01 2.76e-01 -1.72e+03 2.76e-01 2.76e-01 Req: 6.01e+07 6.01e+07 1.00e+12 6.01e+07 6.01e+07 CAP: 0.00e+00 0.00e+00 0.00e+00 0.00e+00 0.00e+00

Name: d:u45:z2 d:u44:z2 d:u43:z2 d:u42:z2 d:u41:z2 Model: dmod2 dmod2 dmod2 dmod2 dmod2 Id: 4.30e-10 4.30e-10 -1.72e-09 4.30e-10 4.30e-10 Vd: 2.76e-01 2.76e-01 -1.72e+03 2.76e-01 2.76e-01 Req: 6.01e+07 6.01e+07 1.00e+12 6.01e+07 6.01e+07 CAP: 0.00e+00 0.00e+00 0.00e+00 0.00e+00 0.00e+00

Name: d:u35:z2 d:u34:z2 d:u33:z2 d:u32:z2 d:u31:z2 Model: dmod2 dmod2 dmod2 dmod2 dmod2 Id: -1.72e-09 -1.72e-09 -5.30e-04 -1.72e-09 -1.72e-09 Vd: -1.72e+03 -1.72e+03 -3.84e+03 -1.72e+03 -1.72e+03 Req: 1.00e+12 1.00e+12 4.88e+01 1.00e+12 1.00e+12 CAP: 0.00e+00 0.00e+00 0.00e+00 0.00e+00 0.00e+00

Name: d:u25:z2 d:u24:z2 d:u23:z2 d:u22:z2 d:u21:z2 Model: dmod2 dmod2 dmod2 dmod2 dmod2 Id: 4.30e-10 4.30e-10 -1.72e-09 4.30e-10 4.30e-10 Vd: 2.76e-01 2.76e-01 -1.72e+03 2.76e-01 2.76e-01 Req: 6.01e+07 6.01e+07 1.00e+12 6.01e+07 6.01e+07 CAP: 0.00e+00 0.00e+00 0.00e+00 0.00e+00 0.00e+00

Name: d:u15:z2 d:u14:z2 d:u13:z2 d:u12:z2 d:u11:z2 Model: dmod2 dmod2 dmod2 dmod2 dmod2 Id: 4.30e-10 4.30e-10 -1.72e-09 4.30e-10 4.30e-10 Vd: 2.76e-01 2.76e-01 -1.72e+03 2.76e-01 2.76e-01 Req: 6.01e+07 6.01e+07 1.00e+12 6.01e+07 6.01e+07 CAP: 0.00e+00 0.00e+00 0.00e+00 0.00e+00 0.00e+00

Name: d:u55:z1 d:u54:z1 d:u53:z1 d:u52:z1 d:u51:z1 Model: dmod1 dmod1 dmod1 dmod1 dmod1 Id: -4.30e-10 -4.30e-10 1.72e-09 -4.30e-10 -4.30e-10 Vd: -3.98e+02 -3.98e+02 3.12e-01 -3.98e+02 -3.98e+02 Req: 8.00e+08 8.00e+08 1.50e+07 8.00e+08 8.00e+08 CAP: 0.00e+00 0.00e+00 0.00e+00 0.00e+00 0.00e+00

Name: d:u45:z1 d:u44:z1 d:u43:z1 d:u42:z1 d:u41:z1 Model: dmod1 dmod1 dmod1 dmod1 dmod1 Id: -4.30e-10 -4.30e-10 1.72e-09 -4.30e-10 -4.30e-10 Vd: -3.98e+02 -3.98e+02 3.12e-01 -3.98e+02 -3.98e+02 Req: 8.00e+08 8.00e+08 1.50e+07 8.00e+08 8.00e+08 CAP: 0.00e+00 0.00e+00 0.00e+00 0.00e+00 0.00e+00

Name: d:u35:z1 d:u34:z1 d:u33:z1 d:u32:z1 d:u31:z1 Model: dmod1 dmod1 dmod1 dmod1 dmod1 Id: 1.72e-09 1.72e-09 5.30e-04 1.72e-09 1.72e-09 Vd: 3.12e-01 3.12e-01 6.39e-01 3.12e-01 3.12e-01 Req: 1.50e+07 1.50e+07 4.88e+01 1.50e+07 1.50e+07 CAP: 0.00e+00 0.00e+00 0.00e+00 0.00e+00 0.00e+00

Name: d:u25:z1 d:u24:z1 d:u23:z1 d:u22:z1 d:u21:z1 Model: dmod1 dmod1 dmod1 dmod1 dmod1 Id: -4.30e-10 -4.30e-10 1.72e-09 -4.30e-10 -4.30e-10 Vd: -3.98e+02 -3.98e+02 3.12e-01 -3.98e+02 -3.98e+02 Req: 8.00e+08 8.00e+08 1.50e+07 8.00e+08 8.00e+08 CAP: 0.00e+00 0.00e+00 0.00e+00 0.00e+00 0.00e+00

Name: d:u15:z1 d:u14:z1 d:u13:z1 d:u12:z1 d:u11:z1 Model: dmod1 dmod1 dmod1 dmod1 dmod1 Id: -4.30e-10 -4.30e-10 1.72e-09 -4.30e-10 -4.30e-10 Vd: -3.98e+02 -3.98e+02 3.12e-01 -3.98e+02 -3.98e+02 Req: 8.00e+08 8.00e+08 1.50e+07 8.00e+08 8.00e+08 CAP: 0.00e+00 0.00e+00 0.00e+00 0.00e+00 0.00e+00

Date: Tue Dec 20 12:09:32 2011 Total elapsed time: 0.112 seconds.

tnom = 27 temp = 27 method = trap totiter = 36 traniter = 0 tranpoints = 0 accept = 0 rejected = 0 matrix size = 36 fillins = 52 solver = Normal Matrix Compiler1: off Matrix Compiler2: off

--
"For a successful technology, reality must take precedence 
over public relations, for nature cannot be fooled."
                                       (Richard Feynman)

• Most likely; have some ideas to try.

• Yep; I knw that it does not matter which device to choose, all of the other paths ("on the line" and "off the line") act the same.

• Ahh...that is the problem! What if there is a bad device - it can give an out-of spec reading for good ones - resulting in a lot of down time especially if testing is done at (say) 185C. The idea is to have something "close" to mass production / testing due to large quantities, and at minimal cost (hence the matrix idea).

• This is a zener and it is impossible to test one at specified currents if a voltage source is used; the zener voltage can be programmed (hence the pun in the device tradename) from 50V to 2500V and was designed as a solid-state replacement to the Victoreen Corotron (a gas-filled glass envelope shunt regulator nominally used with photomultipliers). See our datasheet:

Nope; it is extended to use up to 2Gbytes.

Not too bad; but 4KV with 300K limiting can give 13mA short circuit current; also note * that d:u33:z1 is incorrect; i flagged d:u33:z2 as being reasonable.

I'm not suggesting that that is what to use in practice. It's just convenient as proof-of-concept.

d:u33:z1 and d:u33:z2 are in series, they're each half of the Codatron subcircuit u33. They *must* carry the same current,

Subcircuits get fully expanded in a Spice .op listing.

I see no anomaly.

--
"For a successful technology, reality must take precedence 
over public relations, for nature cannot be fooled."
                                       (Richard Feynman)

Try it, I did, one bad device has no perceptible effect on input current, unless it's the DUT itself, short circuit, open circuit, bad parameters, it doesn't matter.

I figured that.

WHAT??? I do it with a curve tracer all the time.

the zener voltage can be programmed (hence

I thought it might be shaped like a fish, to go downhole easily ;-)

I've read your literature, and prov. pat. app.

I *still* think the device model is inadequate, Read the manual section on diode models.

Better still, do some measurements on a real device, plot some curves, and make a behavioral model that reflects those measurements.

--
"For a successful technology, reality must take precedence 
over public relations, for nature cannot be fooled."
                                       (Richard Feynman)

• For an array 10x14 the sneak currents are huge at 204C and problems with bad devices can create an undesirable reading at the DUT. Problem devices can 1) be effectively shorted (bad results), 2) be very intermittent or arc (again bad), or 3) be effectively open (OK).

• The reference to using a curve tracer is, in a sense, not relevant. One slowly increases the applied voltage to the Izt or specified current point and reads the voltage. In effect, this is what i do by forcing a known current and reading the voltage; works perfectly with devices programmed (so far) from 400V to 2000V. I test at 20uA, 25uA, 30uA, 100uA, 200uA and 500uA; accuracy and repeatability seems to be in the region of 0.1% Typical test temperatures are 20C, 100C and 185C, but -70C, -30C, 0C,

25C, 55C (for the zero TC units that Sandia wanted) and 200C, 204C, 210C have also been used on occasion.

• For this preliminary "matrix" testing scheme it did not matter much. Found too much interaction, so am going "back" to "each on its own" testing, reducing the PCB array from 10Hx14V to 9Hx11V. That means 99 red Teflon wires plus one black Teflon wire from inside the oven going thru / past the door to the outside world where there will be a connector array for the test plug. ((anyone want the "excess" black wire?))

The datasheet shows the curve of real devices. The knee is rather sharp even in the nanoamp region, and there is no negative resistance or oscillations or other zener-like funny-business all the way up to beyond the max spec pulse current rating.

Do not know how to make a model based on (the) data.

Look at the BV specs of the two diodes..