TC1025 comparator spice model

Johan Smit · Dec 21, 2004

Hi,
Can anybody help me with a spice model that will closely simulate the
TC1025 dual comparator please?
Thank you
Johan Smit

Jim Thompson · Dec 22, 2004

On Tue, 21 Dec 2004 05:54:31 +0200, Johan Smit
<smitjsno@spamlantic.net> wrote:

Hi,
Can anybody help me with a spice model that will closely simulate the
TC1025 dual comparator please?
Thank you
Johan Smit

480)460-2350 | |
| E-mail Address at Website Fax

Johan Smit · Dec 23, 2004

On Wed, 22 Dec 2004 08:55:43 -0700, Jim Thompson
<thegreatone@example.com> wrote:

On Tue, 21 Dec 2004 05:54:31 +0200, Johan Smit
smitjsno@spamlantic.net> wrote:

Which simulator are you using?

Hi Jim,

I normally use Swcad3, because it can use the original Spice ascii
libs, which I had from DOS days.
I have others, depending on which lib I can get.
The TC1025 appears nice, rail to rail, and I would like to use it in a
circuit to replace LM393, which has no active pull-up.
If I cannot get a spice model for the TC1025, could you perhaps
recommend a replacement comparator, for low power (battery) use?
Thank you
Johan Smit

Mike Engelhardt · Dec 26, 2004

Jim,

Johan, I have a configurable comparator model, but it uses "tanh" in
the transfer function. Can Swcad3 handle "tanh"?

Of course LTspice does tanh().

--Mike

Johan Smit · Dec 28, 2004

On Sun, 26 Dec 2004 10:21:42 -0700, Jim Thompson
<thegreatone@example.com> wrote:

On Thu, 23 Dec 2004 05:48:54 +0200, Johan Smit
smitjsno@spamlantic.net> wrote:

Hi Jim,

Johan, I have a configurable comparator model, but it uses "tanh" in
the transfer function. Can Swcad3 handle "tanh"?

From the Swcad3 help file:

"LTspice is the circuit simulation engine for the SwitcherCAD III."
and as Mike said, LT Spice can do it.
So I must conclude that Swcad3 can handle tanh.
Looking forward to your module.
Thanks for all the replies.
Regards
Johan Smit

Johan Smit · Dec 31, 2004

On Thu, 30 Dec 2004 08:19:34 -0700, Jim Thompson
<thegreatone@example.com> wrote:

Hi Great One Jim,

Looks fine. Now add power supply CURRENTS ;-)

Thank you.

Could you show me how to do that please?
Best Regards
Johan Smit

Jim Thompson · Dec 26, 2004

On Thu, 23 Dec 2004 05:48:54 +0200, Johan Smit
<smitjsno@spamlantic.net> wrote:

On Wed, 22 Dec 2004 08:55:43 -0700, Jim Thompson
thegreatone@example.com> wrote:

On Tue, 21 Dec 2004 05:54:31 +0200, Johan Smit
smitjsno@spamlantic.net> wrote:

Which simulator are you using?

Hi Jim,
I normally use Swcad3, because it can use the original Spice ascii
libs, which I had from DOS days.
I have others, depending on which lib I can get.
The TC1025 appears nice, rail to rail, and I would like to use it in a
circuit to replace LM393, which has no active pull-up.
If I cannot get a spice model for the TC1025, could you perhaps
recommend a replacement comparator, for low power (battery) use?
Thank you
Johan Smit

480)460-2350 | |
| E-mail Address at Website Fax

Jim Thompson · Dec 26, 2004

On Sun, 26 Dec 2004 17:32:00 GMT, "Mike Engelhardt" <nospam@spam.org>
wrote:

Jim,

Johan, I have a configurable comparator model, but it uses "tanh" in
the transfer function. Can Swcad3 handle "tanh"?

Of course LTspice does tanh().

--Mike

480)460-2350 | |
| E-mail Address at Website Fax

Mike Engelhardt · Dec 26, 2004

Jim,

Johan, I have a configurable comparator model, but it
uses "tanh" in the transfer function. Can Swcad3
handle "tanh"?

Of course LTspice does tanh().

--Mike

I figured it did. What is the syntax?

You can just use PSpice syntax in LTspice. If
you're interested, LTspice's native syntax is
documented in the help section (F1 Key)=>
LTspice=>Circuit Elements=>B. Arbitrary
behavioral voltage or current sources.

But it runs PSpice macromodel syntax flawlessly.

--Mike

Jim Thompson · Dec 29, 2004

On Tue, 28 Dec 2004 08:36:12 +0200, Johan Smit
<smitjsno@spamlantic.net> wrote:

On Sun, 26 Dec 2004 10:21:42 -0700, Jim Thompson
thegreatone@example.com> wrote:

On Thu, 23 Dec 2004 05:48:54 +0200, Johan Smit
smitjsno@spamlantic.net> wrote:

Hi Jim,

Johan, I have a configurable comparator model, but it uses "tanh" in
the transfer function. Can Swcad3 handle "tanh"?

From the Swcad3 help file:
"LTspice is the circuit simulation engine for the SwitcherCAD III."
and as Mike said, LT Spice can do it.
So I must conclude that Swcad3 can handle tanh.
Looking forward to your module.
Thanks for all the replies.
Regards
Johan Smit

Hi Johan, I think the following is correct... I had to re-write it in
subcircuit format... it is from some of my old stuff where I used to
place everything inside the symbol. Give it a whirl. If it balks,
let me know.

..SUBCKT CompBeh INP INN OUT PARAMS: HIGH=5 LOW=0 DELTA=5m T=10n
** HIGH = High Output Level (Volts)
** LOW = Low Output Level (Volts)
** DELTA = Transition Width (Input, Volts)
** T = Delay
R1 int1 0 1G
R2 int1 int2 {SQRT(T/0.693147)}
C1 int2 0 {SQRT(T/0.693147)}
E2 OUT 0 VALUE = {V(int2,0)*(HIGH-LOW)+LOW}
E1 int1 0 VALUE = {(tanh(A*V(INP,INN))+1)/2}
..PARAM A = 2.197774/DELTA
..ENDS CompBeh

...Jim Thompson
--
| James E.Thompson, P.E. | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona Voice

480)460-2350 | |
| E-mail Address at Website Fax

Johan Smit · Dec 30, 2004

On Wed, 29 Dec 2004 14:04:26 -0700, Jim Thompson
<thegreatone@example.com> wrote:

Hi Johan, I think the following is correct... I had to re-write it in
subcircuit format... it is from some of my old stuff where I used to
place everything inside the symbol. Give it a whirl. If it balks,
let me know.

Hi Great One Jim,
I changed a few things to add the supply connections.
Here is the .Lib file :

..SUBCKT CompCMOS 1 2 3 4 5 PARAMS: DELTA=5m T=10n
** DELTA = Transition Width (Input, Volts)
** T = Delay
R1 int1 4 1G
R2 int1 int2 {SQRT(T/0.693147)}
C1 int2 4 {SQRT(T/0.693147)}
E2 5 4 VALUE = {V(int2,4)*V(3,4)+V(4)}
E1 int1 4 VALUE = {(tanh(A*V(1,2))+1)/2}
..PARAM A = 2.197774/DELTA
..ENDS CompCMOS

and the little capacity controlled oscillator

VS1025.CIR
..LIB CompCMOS.LIB
Vsupply Vs 0 3v
R1 2 5 1MEG
R2 5 7 470K
R3 6 7 220K
R4 1 2 220K
R5 7 0 100K ;load
C1 2 6 100PF ;CX
C2 2 0 200PF ;stray
C3 6 0 200PF ;stray
C4 Vs 0 100NF ;decoupling
XCOMP1 5 6 Vs 0 7 CompCMOS
XCOMP2 6 7 Vs 0 1 CompCMOS
..IC V(2)=1v
..tran 0.1u 1m 0 0
..probe

Works like a charm, but please check if I had not made a fool of
myself somewhere. I have done it before.
Thanks very much
Best Regards
Johan Smit

Jim Thompson · Dec 30, 2004

On Thu, 30 Dec 2004 16:09:35 +0200, Johan Smit
<smitjsno@spamlantic.net> wrote:

On Wed, 29 Dec 2004 14:04:26 -0700, Jim Thompson
thegreatone@example.com> wrote:

Hi Johan, I think the following is correct... I had to re-write it in
subcircuit format... it is from some of my old stuff where I used to
place everything inside the symbol. Give it a whirl. If it balks,
let me know.

Hi Great One Jim,
I changed a few things to add the supply connections.
Here is the .Lib file :

.SUBCKT CompCMOS 1 2 3 4 5 PARAMS: DELTA=5m T=10n
** DELTA = Transition Width (Input, Volts)
** T = Delay
R1 int1 4 1G
R2 int1 int2 {SQRT(T/0.693147)}
C1 int2 4 {SQRT(T/0.693147)}
E2 5 4 VALUE = {V(int2,4)*V(3,4)+V(4)}
E1 int1 4 VALUE = {(tanh(A*V(1,2))+1)/2}
.PARAM A = 2.197774/DELTA
.ENDS CompCMOS

and the little capacity controlled oscillator

VS1025.CIR
.LIB CompCMOS.LIB
Vsupply Vs 0 3v
R1 2 5 1MEG
R2 5 7 470K
R3 6 7 220K
R4 1 2 220K
R5 7 0 100K ;load
C1 2 6 100PF ;CX
C2 2 0 200PF ;stray
C3 6 0 200PF ;stray
C4 Vs 0 100NF ;decoupling
XCOMP1 5 6 Vs 0 7 CompCMOS
XCOMP2 6 7 Vs 0 1 CompCMOS
.IC V(2)=1v
.tran 0.1u 1m 0 0
.probe

Works like a charm, but please check if I had not made a fool of
myself somewhere. I have done it before.
Thanks very much
Best Regards
Johan Smit

480)460-2350 | |
| E-mail Address at Website Fax

Mike Engelhardt · Dec 31, 2004

Johan,

Hi Great One Jim,

Looks fine. Now add power supply CURRENTS ;-)

Thank you.
Could you show me how to do that please?

You might just use the LTspice device "1pole".
It's a behavioral opamp with a tanh() xfer
function. Using the rail-to-rail opamp without
feedback approximates a comparator. The 1pole
does steer current from the supplies to the
output. Also, the 1pole uses the tanh() xfer
function that's part of an intrinsic SPICE
device that knows how to help the solver find
the solution with higher than just the 1st
order information that's usually available to
the solver's Newton iteration. The behavioral
modeling like Jim's is using can't do that.

--Mike

Johan Smit · Dec 31, 2004

On Fri, 31 Dec 2004 06:24:41 GMT, "Mike Engelhardt" <nospam@spam.org>
wrote:

You might just use the LTspice device "1pole".
It's a behavioral opamp with a tanh() xfer
function. Using the rail-to-rail opamp without
feedback approximates a comparator. The 1pole
does steer current from the supplies to the
output. Also, the 1pole uses the tanh() xfer
function that's part of an intrinsic SPICE
device that knows how to help the solver find
the solution with higher than just the 1st
order information that's usually available to
the solver's Newton iteration. The behavioral
modeling like Jim's is using can't do that.

Hi Mike,

Thank you. I must admit that my knowledge is lacking.
I have changed to the following:
VS1025A.CIR
..LIB CompCMOS.Lib
Vsupply Vs 0 3v
R1 2 5 1MEG
R2 5 7 470K
R3 6 7 220K
R4 1 2 220K
R5 7 0 100K ;load
C1 2 6 100PF ;CX
C2 2 0 200PF ;stray
C3 6 0 200PF ;stray
C4 Vs 0 100NF ;decoupling
XCOMP1 5 6 Vs 0 7 1pole
XCOMP2 6 7 Vs 0 1 1pole
..IC V(2)=1v
..tran 0.1u 1m 0 0
..probe
..ends VS1025A
*-------------------------------------------------------
..subckt 1pole 1 2 3 4 5
S1 5 3 N002 5 Q
S2 4 5 5 N002 Q
A1 2 1 0 0 0 0 N002 0 OTA G={Avol/Rout} ref={Vos} Iout={slew*Cout}
Cout={Cout} en={en} enk={enk} in={in} ink={ink} Vhigh=1e308
Vlow=-1e308
C3 5 4 1p
C4 3 5 1p
S3 N002 0 4 N002 C
S4 0 N002 N002 3 C
R2 N002 4 {2*Rout} noiseless
R1 3 N002 {2*Rout} noiseless
R3 3 1 1G noiseless
R4 3 2 1G noiseless
R5 2 4 1G noiseless
R6 1 4 1G noiseless
..model C SW(Ron=100 Roff=1T Vt=0 Vh=-1 noiseless)
..param Rout=100Meg
..param Cout={Avol/GBW/2/pi/Rout}
..model Q SW(Ron=10 Roff=10Meg Vt=0 Vh=-.1 Vser={Rail} ilimit={Ilimit}
noiseless)
..param Avol=1Meg GBW=10Meg Slew=10Meg ilimit=25m rail=0 Vos=0
..param en=0 enk=0 in=0 ink=0
..ends 1pole

The currents are now shown.
Now how to adjust the delay and the transition window to the specs?
Thank you
Regards
Johan Smit

Mike Engelhardt · Dec 31, 2004

Johan ,

You might just use the LTspice device "1pole".
It's a behavioral opamp with a tanh() xfer
function. Using the rail-to-rail opamp without
feedback approximates a comparator. The 1pole
does steer current from the supplies to the
output. Also, the 1pole uses the tanh() xfer
function that's part of an intrinsic SPICE
device that knows how to help the solver find
the solution with higher than just the 1st
order information that's usually available to
the solver's Newton iteration. The behavioral
modeling like Jim's is using can't do that.

Hi Mike,
Thank you. I must admit that my knowledge is lacking.
I have changed to the following:
VS1025A.CIR
.LIB CompCMOS.Lib
Vsupply Vs 0 3v
R1 2 5 1MEG
R2 5 7 470K
R3 6 7 220K
R4 1 2 220K
R5 7 0 100K ;load
C1 2 6 100PF ;CX
C2 2 0 200PF ;stray
C3 6 0 200PF ;stray
C4 Vs 0 100NF ;decoupling
XCOMP1 5 6 Vs 0 7 1pole
XCOMP2 6 7 Vs 0 1 1pole
.IC V(2)=1v
.tran 0.1u 1m 0 0
.probe
.ends VS1025A
*-------------------------------------------------------
.subckt 1pole 1 2 3 4 5
S1 5 3 N002 5 Q
S2 4 5 5 N002 Q
A1 2 1 0 0 0 0 N002 0 OTA G={Avol/Rout} ref={Vos} Iout={slew*Cout}
Cout={Cout} en={en} enk={enk} in={in} ink={ink} Vhigh=1e308
Vlow=-1e308
C3 5 4 1p
C4 3 5 1p
S3 N002 0 4 N002 C
S4 0 N002 N002 3 C
R2 N002 4 {2*Rout} noiseless
R1 3 N002 {2*Rout} noiseless
R3 3 1 1G noiseless
R4 3 2 1G noiseless
R5 2 4 1G noiseless
R6 1 4 1G noiseless
.model C SW(Ron=100 Roff=1T Vt=0 Vh=-1 noiseless)
.param Rout=100Meg
.param Cout={Avol/GBW/2/pi/Rout}
.model Q SW(Ron=10 Roff=10Meg Vt=0 Vh=-.1 Vser={Rail} ilimit={Ilimit}
noiseless)
.param Avol=1Meg GBW=10Meg Slew=10Meg ilimit=25m rail=0 Vos=0
.param en=0 enk=0 in=0 ink=0
.ends 1pole

The currents are now shown.
Now how to adjust the delay and the transition window to the specs?

I think you can adjust the transition well enough
with the DC gain(Avol). The GBW and slew will
adjust the delay but not independently of the
rise and fall times. You'd have to try different
values and see if you can get the behavior as you
like. The basic thought to this is that as a
comparator can be used as an opamp, an opamp can
be used as a comparator. You might be able to
adjust the delay a bit by using the level 3b of the
UniversalOpamp. It has delay line implemented in
a few pi sections. The amount of delay is specified
by the phase margin.

--Mike

Jim Thompson · Dec 31, 2004

On Fri, 31 Dec 2004 06:24:41 GMT, "Mike Engelhardt" <nospam@spam.org>
wrote:

Johan,

Hi Great One Jim,

Looks fine. Now add power supply CURRENTS ;-)

Thank you.
Could you show me how to do that please?

You might just use the LTspice device "1pole".
It's a behavioral opamp with a tanh() xfer
function. Using the rail-to-rail opamp without
feedback approximates a comparator. The 1pole
does steer current from the supplies to the
output. Also, the 1pole uses the tanh() xfer
function that's part of an intrinsic SPICE
device that knows how to help the solver find
the solution with higher than just the 1st
order information that's usually available to
the solver's Newton iteration. The behavioral
modeling like Jim's is using can't do that.

--Mike

480)460-2350 | |
| E-mail Address at Website Fax

Mike Engelhardt · Dec 31, 2004

Jim,

Hi Great One Jim,

Looks fine. Now add power supply CURRENTS ;-)

Thank you.
Could you show me how to do that please?

You might just use the LTspice device "1pole".
It's a behavioral opamp with a tanh() xfer
function. Using the rail-to-rail opamp without
feedback approximates a comparator. The 1pole
does steer current from the supplies to the
output. Also, the 1pole uses the tanh() xfer
function that's part of an intrinsic SPICE
device that knows how to help the solver find
the solution with higher than just the 1st
order information that's usually available to
the solver's Newton iteration. The behavioral
modeling like Jim's is using can't do that.

Tanh works just ducky in PSpice, or anywhere
else for that matter...it allows bounding
without discontinuities.

Yes, it can run "just ducky" in simple
simulations. But as the complexity increases,
especially if the behavioral devices are
found in feedback loops, you've have a
progressively more difficult time with
convergence problems when using a function
like atanh() as a behavioral expression
as contrasted with using it as part of a
properly written intrinsic SPICE device.

There's a difference between using a
transcendental like tanh() in an intrinsic
device and using it in a behavioral expression.
When implemented in an intrinsic device; almost
any SPICE, at least both PSpice and LTspice; is
aware of how to fix problems that arise in the
Newton iteration method. Newton-Raphson is a
1st order method that can run into trouble
finding the solution of multi-dimensional non-
inear systems like circuits. The types of
techniques used in intrinsic SPICE devices like
semiconductors can't be applied to general
behavioral expressions using atanh().

--Mike

Jim Thompson · Dec 31, 2004

On Fri, 31 Dec 2004 20:06:58 GMT, "Mike Engelhardt" <nospam@spam.org>
wrote:

Jim,

Hi Great One Jim,

Looks fine. Now add power supply CURRENTS ;-)

Thank you.
Could you show me how to do that please?

You might just use the LTspice device "1pole".
It's a behavioral opamp with a tanh() xfer
function. Using the rail-to-rail opamp without
feedback approximates a comparator. The 1pole
does steer current from the supplies to the
output. Also, the 1pole uses the tanh() xfer
function that's part of an intrinsic SPICE
device that knows how to help the solver find
the solution with higher than just the 1st
order information that's usually available to
the solver's Newton iteration. The behavioral
modeling like Jim's is using can't do that.

Tanh works just ducky in PSpice, or anywhere
else for that matter...it allows bounding
without discontinuities.

Yes, it can run "just ducky" in simple
simulations. But as the complexity increases,
especially if the behavioral devices are
found in feedback loops, you've have a
progressively more difficult time with
convergence problems when using a function
like atanh() as a behavioral expression
as contrasted with using it as part of a
properly written intrinsic SPICE device.

There's a difference between using a
transcendental like tanh() in an intrinsic
device and using it in a behavioral expression.
When implemented in an intrinsic device; almost
any SPICE, at least both PSpice and LTspice; is
aware of how to fix problems that arise in the
Newton iteration method. Newton-Raphson is a
1st order method that can run into trouble
finding the solution of multi-dimensional non-
inear systems like circuits. The types of
techniques used in intrinsic SPICE devices like
semiconductors can't be applied to general
behavioral expressions using atanh().

--Mike

480)460-2350 | |
| E-mail Address at Website Fax

Mike Engelhardt · Dec 31, 2004

Jim,

Hi Great One Jim,

Looks fine. Now add power supply CURRENTS ;-)

Thank you.
Could you show me how to do that please?

You might just use the LTspice device "1pole".
It's a behavioral opamp with a tanh() xfer
function. Using the rail-to-rail opamp without
feedback approximates a comparator. The 1pole
does steer current from the supplies to the
output. Also, the 1pole uses the tanh() xfer
function that's part of an intrinsic SPICE
device that knows how to help the solver find
the solution with higher than just the 1st
order information that's usually available to
the solver's Newton iteration. The behavioral
modeling like Jim's is using can't do that.

Tanh works just ducky in PSpice, or anywhere
else for that matter...it allows bounding
without discontinuities.

Yes, it can run "just ducky" in simple
simulations. But as the complexity increases,
especially if the behavioral devices are
found in feedback loops, you've have a
progressively more difficult time with
convergence problems when using a function
like atanh() as a behavioral expression
as contrasted with using it as part of a
properly written intrinsic SPICE device.

There's a difference between using a
transcendental like tanh() in an intrinsic
device and using it in a behavioral expression.
When implemented in an intrinsic device; almost
any SPICE, at least both PSpice and LTspice; is
aware of how to fix problems that arise in the
Newton iteration method. Newton-Raphson is a
1st order method that can run into trouble
finding the solution of multi-dimensional non-
inear systems like circuits. The types of
techniques used in intrinsic SPICE devices like
semiconductors can't be applied to general
behavioral expressions using atanh().

--Mike

I didn't say "atanh", I said "tanh"

I *did* say tanh(), but also mistyped it
as atanh(). My point applies for all
transcendentals. There's an advantage
to using intrinsic SPICE devices over
behavioral sources for SPICE machines
designed with knowledge over 1st
order in the transcendental functions
used to describe the device.

--Mike

Johan Smit · Jan 1, 2005

On Fri, 31 Dec 2004 16:00:48 GMT, "Mike Engelhardt" <nospam@spam.org>
wrote:

I think you can adjust the transition well enough
with the DC gain(Avol). The GBW and slew will
adjust the delay but not independently of the
rise and fall times. You'd have to try different
values and see if you can get the behavior as you
like. The basic thought to this is that as a
comparator can be used as an opamp, an opamp can
be used as a comparator. You might be able to
adjust the delay a bit by using the level 3b of the
UniversalOpamp. It has delay line implemented in
a few pi sections. The amount of delay is specified
by the phase margin.

Hi Mike and Jim,

Thank you both very much.
I have learnt from you both and am richer in having at least two nice
additional methods to call.
Thank you.
Best Regards
Johan Smit

TC1025 comparator spice model

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