L
Lostgallifreyan
Guest
Hello. I found a model for the CA3140 on a web archive of this group, from an
old post (2003) and not found any other examples, so I guess people have been
happy with it, but it won't work for me.
I usually ended up using something else aimed at a specific task, but the
thing still bothers me enough to want to know what to do to make it work. I
always see it start spicing with the iterations in LTspice that I know so
nothing about, except that if a circuit does too much of that it usually
means I'm doing somethign wrong that makes it chew some intractable problem I
ought not to be forcing it into...
So I try the very simplest task an op-amp can ever be asked to do: supply it
with power, make it a voltage follwer, fed by a divider made from two 1K
resistors across the supply. Surely it ought to run in very short order,
outputting half the supply plus its input voltage offset. But it won't, as
ever, it chews intractably, and if I force the simulation to end it puts up
an error:
Time step too small; initial timepoint: trouble with u1:md3-instance d:u1:d3
If anyone wants it I can follow up this post with the log content but not
right now, this post is already big enough..
My model file has only one mod from the copy now all over the web (other
than the .subckt name to match my symbol). This is to put a single line
(commented out) for the CA3140A variant because apart from that line, the
models are identical, and I preferred to reduce the original to half, for
now.
The model is as follows, and if anyone else gets the same failure in LTspice
when testing this for a simple follower (or any other task, apparently),
please let me know, and if possible, how to make it work. I have little if
any trouble gettign several other things to work, so I think there's
somethign wrong with this file.
*$ model description: "awbca3140"
*a Device model created by analog_uprev for ca3140 on Thu Mar 1 18:48:14 IST
2001
* CONNECTIONS: NON-INVERTING INPUT
* | INVERTING INPUT
* | | POSITIVE POWER SUPPLY
* | | | NEGATIVE POWER SUPPLY
* | | | | OUTPUT
* | | | | |
..subckt CA3140 1 36 15 20 12
*START OF DECK
* +IN -IN OUT +VSS -VSS
*NODE: 1 36 15 20 12
*------INPUT STAGE-------
VOSBAL 7 29 3.00000000E-03
EU1 8 1 20 12 0.0001
EU2 8 7 5 12 -1
RB1 12 10 1 TC= 1.991040E-03 (-1.244400E-04)
IB4 10 12 1.000000E-06
RB3 12 5 8743.17 TC= 1.60000000E-03 (0.00000000E+00)
*IB3 for CA3140, and CA3140A
IB3 12 5 5.718750E-07
*IB3 12 5 2.287500E-07
G1 12 1 10 12 1.025000E-05
G2 12 36 10 12 9.750000E-06
RDM 36 29 1.500000E+12
RCM 31 13 1.500000E+12
CDM 36 29 4.000000E-12
G5 31 13 36 31 6.66667E-13
G6 31 13 1 31 6.66667E-13
*------INTERMEDIATE STAGE-------
GDM 31 16 29 36 1
GCM 31 16 13 31 -1.58113883E-05
R1 31 16 3.16358380E+02
C1 31 16 6.45457E-11
VCP 23 31 100
VCM 24 31 -100
DD1 16 23 MD2
..MODEL MD2 D XTI=1.000000P
* SPECTRE: + IMAX=1000
DD2 24 16 MD2
G3 31 6 16 31 -1.07249255E-06
R2 31 6 100000
C2 11 6 1.2E-11
RP1 31 20 3750
RP2 31 12 3750
*------OUTPUT STAGE-------
G4 31 11 6 31 -5.10867719E+01
ROUT 31 11 60
DD3 11 9 MD3
..MODEL MD3 D IS=10.0F XTI=1.0P N= 3.612647E-01
* SPECTRE: + IMAX=1000
DD4 9 11 MD4
..MODEL MD4 D IS=10.0F XTI=1.0P N= 8.028126E-01
* SPECTRE: + IMAX=1000
EU6 9 31 2 31 1
RO1 11 26 20
FF1 31 28 VFF1 1
VFF1 26 2 0.0
FF2 31 20 VFF2 -1
VFF2 33 31 0.0
FF3 12 31 VFF3 -1
VFF3 31 27 0.0
DD8 27 28 MID
DD7 28 33 MID
..MODEL MID D XTI=1.000000F N=1 IS=10.000000F
* SPECTRE: + IMAX=1000
VP 20 22 -29.2613
VM 21 12 -29.3113
DD5 25 22 MID
DD6 21 17 MID
VP1 20 30 2.7501
VM1 32 12 .859456
DD9 2 30 MD9
DD10 32 15 MD9
..MODEL MD9 D XTI=1.000000F N=1 IS=10.000000F
* SPECTRE: + IMAX=1000
HH1 25 2 POLY(2) VIC2 VIC1 0 1960 0 1540 0 0 0 0 0 0
HH2 2 17 POLY(2) VIC3 VIC1 0 -1960 0 -1540 0 0 0 0 0 0
VIC1 37 3 0.0
VIC2 2 14 0.0
VIC3 14 15 0.0
VPP 37 0 1
RPP 3 0 100.0K
RO3 15 20 200.0MEG
RO2 15 12 200.0MEG
..ends
*$ end model description: "awbca3140"
old post (2003) and not found any other examples, so I guess people have been
happy with it, but it won't work for me.
I usually ended up using something else aimed at a specific task, but the
thing still bothers me enough to want to know what to do to make it work. I
always see it start spicing with the iterations in LTspice that I know so
nothing about, except that if a circuit does too much of that it usually
means I'm doing somethign wrong that makes it chew some intractable problem I
ought not to be forcing it into...
So I try the very simplest task an op-amp can ever be asked to do: supply it
with power, make it a voltage follwer, fed by a divider made from two 1K
resistors across the supply. Surely it ought to run in very short order,
outputting half the supply plus its input voltage offset. But it won't, as
ever, it chews intractably, and if I force the simulation to end it puts up
an error:
Time step too small; initial timepoint: trouble with u1:md3-instance d:u1:d3
If anyone wants it I can follow up this post with the log content but not
right now, this post is already big enough..
My model file has only one mod from the copy now all over the web (other
than the .subckt name to match my symbol). This is to put a single line
(commented out) for the CA3140A variant because apart from that line, the
models are identical, and I preferred to reduce the original to half, for
now.
The model is as follows, and if anyone else gets the same failure in LTspice
when testing this for a simple follower (or any other task, apparently),
please let me know, and if possible, how to make it work. I have little if
any trouble gettign several other things to work, so I think there's
somethign wrong with this file.
*$ model description: "awbca3140"
*a Device model created by analog_uprev for ca3140 on Thu Mar 1 18:48:14 IST
2001
* CONNECTIONS: NON-INVERTING INPUT
* | INVERTING INPUT
* | | POSITIVE POWER SUPPLY
* | | | NEGATIVE POWER SUPPLY
* | | | | OUTPUT
* | | | | |
..subckt CA3140 1 36 15 20 12
*START OF DECK
* +IN -IN OUT +VSS -VSS
*NODE: 1 36 15 20 12
*------INPUT STAGE-------
VOSBAL 7 29 3.00000000E-03
EU1 8 1 20 12 0.0001
EU2 8 7 5 12 -1
RB1 12 10 1 TC= 1.991040E-03 (-1.244400E-04)
IB4 10 12 1.000000E-06
RB3 12 5 8743.17 TC= 1.60000000E-03 (0.00000000E+00)
*IB3 for CA3140, and CA3140A
IB3 12 5 5.718750E-07
*IB3 12 5 2.287500E-07
G1 12 1 10 12 1.025000E-05
G2 12 36 10 12 9.750000E-06
RDM 36 29 1.500000E+12
RCM 31 13 1.500000E+12
CDM 36 29 4.000000E-12
G5 31 13 36 31 6.66667E-13
G6 31 13 1 31 6.66667E-13
*------INTERMEDIATE STAGE-------
GDM 31 16 29 36 1
GCM 31 16 13 31 -1.58113883E-05
R1 31 16 3.16358380E+02
C1 31 16 6.45457E-11
VCP 23 31 100
VCM 24 31 -100
DD1 16 23 MD2
..MODEL MD2 D XTI=1.000000P
* SPECTRE: + IMAX=1000
DD2 24 16 MD2
G3 31 6 16 31 -1.07249255E-06
R2 31 6 100000
C2 11 6 1.2E-11
RP1 31 20 3750
RP2 31 12 3750
*------OUTPUT STAGE-------
G4 31 11 6 31 -5.10867719E+01
ROUT 31 11 60
DD3 11 9 MD3
..MODEL MD3 D IS=10.0F XTI=1.0P N= 3.612647E-01
* SPECTRE: + IMAX=1000
DD4 9 11 MD4
..MODEL MD4 D IS=10.0F XTI=1.0P N= 8.028126E-01
* SPECTRE: + IMAX=1000
EU6 9 31 2 31 1
RO1 11 26 20
FF1 31 28 VFF1 1
VFF1 26 2 0.0
FF2 31 20 VFF2 -1
VFF2 33 31 0.0
FF3 12 31 VFF3 -1
VFF3 31 27 0.0
DD8 27 28 MID
DD7 28 33 MID
..MODEL MID D XTI=1.000000F N=1 IS=10.000000F
* SPECTRE: + IMAX=1000
VP 20 22 -29.2613
VM 21 12 -29.3113
DD5 25 22 MID
DD6 21 17 MID
VP1 20 30 2.7501
VM1 32 12 .859456
DD9 2 30 MD9
DD10 32 15 MD9
..MODEL MD9 D XTI=1.000000F N=1 IS=10.000000F
* SPECTRE: + IMAX=1000
HH1 25 2 POLY(2) VIC2 VIC1 0 1960 0 1540 0 0 0 0 0 0
HH2 2 17 POLY(2) VIC3 VIC1 0 -1960 0 -1540 0 0 0 0 0 0
VIC1 37 3 0.0
VIC2 2 14 0.0
VIC3 14 15 0.0
VPP 37 0 1
RPP 3 0 100.0K
RO3 15 20 200.0MEG
RO2 15 12 200.0MEG
..ends
*$ end model description: "awbca3140"
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