Got annoyed at the flaky 555 models that are out there, so I rolled my
own...

http://www.analog-innovations.com/SED/MyLMC555.zip

Based on old AMI 20V CMOS device models, mostly form/fit/function with
CMOS, but some behavioral on the front-end where it doesn't matter.

Optimized and fitted to National LMC555 at 5V operation. It'll work
at other voltages but may sink/source more or less than spec at other
voltages because of ancient 5u devices :-)

Try it out and let me know.

...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 | |
| Voice480)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.

"Jim Thompson" schrieb
im Newsbeitrag ...
Got annoyed at the flaky 555 models that are out there, so I rolled my
own...

http://www.analog-innovations.com/SED/MyLMC555.zip

Based on old AMI 20V CMOS device models, mostly form/fit/function with
CMOS, but some behavioral on the front-end where it doesn't matter.

Optimized and fitted to National LMC555 at 5V operation. It'll work
at other voltages but may sink/source more or less than spec at other
voltages because of ancient 5u devices :-)

Try it out and let me know.

...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 | |
| Voice480)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.


Hello Jim,

Thanks a lot for this model.

I have made an example with your model and uploaded it to the Yahoo group.

Files Lib CMOS Timers TLC555, TLC556, LMC555 Example LMC555
http://tech.groups.yahoo.com/group/L...mple%20LMC555/

Best regards,
Helmut

"Jim Thompson" schrieb
im Newsbeitrag ...
Got annoyed at the flaky 555 models that are out there, so I rolled my
own...

http://www.analog-innovations.com/SED/MyLMC555.zip

Based on old AMI 20V CMOS device models, mostly form/fit/function with
CMOS, but some behavioral on the front-end where it doesn't matter.

Optimized and fitted to National LMC555 at 5V operation. It'll work
at other voltages but may sink/source more or less than spec at other
voltages because of ancient 5u devices :-)

Try it out and let me know.

...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 | |
| Voice480)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.


Hello Jim,

Thanks a lot for this model.

I have made an example with your model and uploaded it to the Yahoo group.

Files Lib CMOS Timers TLC555, TLC556, LMC555 Example LMC555
http://tech.groups.yahoo.com/group/L...mple%20LMC555/

Best regards,
Helmut

On Sat, 19 Mar 2011 00:52:38 +0100, "Helmut Sennewald"
wrote:

"Jim Thompson" schrieb
im Newsbeitrag ...
Got annoyed at the flaky 555 models that are out there, so I rolled my
own...

http://www.analog-innovations.com/SED/MyLMC555.zip

Based on old AMI 20V CMOS device models, mostly form/fit/function with
CMOS, but some behavioral on the front-end where it doesn't matter.

Optimized and fitted to National LMC555 at 5V operation. It'll work
at other voltages but may sink/source more or less than spec at other
voltages because of ancient 5u devices :-)

Try it out and let me know.

...Jim Thompson
[snip]


Hello Jim,

Thanks a lot for this model.

I have made an example with your model and uploaded it to the Yahoo group.

Files Lib CMOS Timers TLC555, TLC556, LMC555 Example LMC555
http://tech.groups.yahoo.com/group/L...mple%20LMC555/

Best regards,
Helmut


Thanks, Helmut!

Let me know of any complaints!

...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 | |
| Voice480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |

Remember: Once you go over the hill, you pick up speed

"Jim Thompson" schrieb
im Newsbeitrag ...
On Sat, 19 Mar 2011 00:52:38 +0100, "Helmut Sennewald"
wrote:

"Jim Thompson" schrieb
im Newsbeitrag ...
Got annoyed at the flaky 555 models that are out there, so I rolled my
own...

http://www.analog-innovations.com/SED/MyLMC555.zip

Based on old AMI 20V CMOS device models, mostly form/fit/function with
CMOS, but some behavioral on the front-end where it doesn't matter.

Optimized and fitted to National LMC555 at 5V operation. It'll work
at other voltages but may sink/source more or less than spec at other
voltages because of ancient 5u devices :-)

Try it out and let me know.

...Jim Thompson
[snip]


Hello Jim,

Thanks a lot for this model.

I have made an example with your model and uploaded it to the Yahoo group.

Files Lib CMOS Timers TLC555, TLC556, LMC555 Example LMC555
http://tech.groups.yahoo.com/group/L...mple%20LMC555/

Best regards,
Helmut


Thanks, Helmut!

Let me know of any complaints!

...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 | |
| Voice480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |

Remember: Once you go over the hill, you pick up speed

Hello Jim,

I have to use ".ic V(timing_cap)=0" to get the simulation quickly started.

Best regards,
Helmut

"Jim Thompson" schrieb
im Newsbeitrag ...
On Sat, 19 Mar 2011 00:52:38 +0100, "Helmut Sennewald"
wrote:

"Jim Thompson" schrieb
im Newsbeitrag ...
Got annoyed at the flaky 555 models that are out there, so I rolled my
own...

http://www.analog-innovations.com/SED/MyLMC555.zip

Based on old AMI 20V CMOS device models, mostly form/fit/function with
CMOS, but some behavioral on the front-end where it doesn't matter.

Optimized and fitted to National LMC555 at 5V operation. It'll work
at other voltages but may sink/source more or less than spec at other
voltages because of ancient 5u devices :-)

Try it out and let me know.

...Jim Thompson
[snip]


Hello Jim,

Thanks a lot for this model.

I have made an example with your model and uploaded it to the Yahoo group.

Files Lib CMOS Timers TLC555, TLC556, LMC555 Example LMC555
http://tech.groups.yahoo.com/group/L...mple%20LMC555/

Best regards,
Helmut


Thanks, Helmut!

Let me know of any complaints!

...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 | |
| Voice480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |

Remember: Once you go over the hill, you pick up speed

Hello Jim,

I have to use ".ic V(timing_cap)=0" to get the simulation quickly started.

Best regards,
Helmut

On Sat, 19 Mar 2011 01:15:23 +0100, "Helmut Sennewald"
wrote:


"Jim Thompson" schrieb
im Newsbeitrag ...
On Sat, 19 Mar 2011 00:52:38 +0100, "Helmut Sennewald"
wrote:

"Jim Thompson" schrieb
im Newsbeitrag ...
Got annoyed at the flaky 555 models that are out there, so I rolled my
own...

http://www.analog-innovations.com/SED/MyLMC555.zip

Based on old AMI 20V CMOS device models, mostly form/fit/function with
CMOS, but some behavioral on the front-end where it doesn't matter.

Optimized and fitted to National LMC555 at 5V operation. It'll work
at other voltages but may sink/source more or less than spec at other
voltages because of ancient 5u devices :-)

Try it out and let me know.

...Jim Thompson
[snip]


Hello Jim,

Thanks a lot for this model.

I have made an example with your model and uploaded it to the Yahoo group.

Files Lib CMOS Timers TLC555, TLC556, LMC555 Example LMC555
http://tech.groups.yahoo.com/group/L...mple%20LMC555/

Best regards,
Helmut


Thanks, Helmut!

Let me know of any complaints!

...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 | |
| Voice480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |

Remember: Once you go over the hill, you pick up speed

Hello Jim,

I have to use ".ic V(timing_cap)=0" to get the simulation quickly started.

Best regards,
Helmut


Same here. Otherwise the latch doesn't know "high" from "low" ;-)

Or just RESETbar to initialize.

...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 | |
| Voice480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |

Remember: Once you go over the hill, you pick up speed

On 3/18/2011 7:13 PM, Jim Thompson wrote:
Got annoyed at the flaky 555 models that are out there, so I rolled my
own...

http://www.analog-innovations.com/SED/MyLMC555.zip

Based on old AMI 20V CMOS device models, mostly form/fit/function with
CMOS, but some behavioral on the front-end where it doesn't matter.

Optimized and fitted to National LMC555 at 5V operation. It'll work
at other voltages but may sink/source more or less than spec at other
voltages because of ancient 5u devices :-)

Try it out and let me know.

...Jim Thompson

Hi Jim,

Thanks for taking the time to create this model. I was doing some
experimenting with it and comparing it to the standard bipolar 555
model, and noticed that the CMOS model seems to have significantly
greater shoot-through current than the bipolar model. I haven't used a
CMOS 555 or measured those currents "in real life", so I'm curious if
that is a real difference, or perhaps the bipolar 555 models don't model
it effectively?

On 3/18/2011 7:13 PM, Jim Thompson wrote:
Got annoyed at the flaky 555 models that are out there, so I rolled my
own...

http://www.analog-innovations.com/SED/MyLMC555.zip

Based on old AMI 20V CMOS device models, mostly form/fit/function with
CMOS, but some behavioral on the front-end where it doesn't matter.

Optimized and fitted to National LMC555 at 5V operation. It'll work
at other voltages but may sink/source more or less than spec at other
voltages because of ancient 5u devices :-)

Try it out and let me know.

...Jim Thompson

Hi Jim,

Thanks for taking the time to create this model. I was doing some
experimenting with it and comparing it to the standard bipolar 555
model, and noticed that the CMOS model seems to have significantly
greater shoot-through current than the bipolar model. I haven't used a
CMOS 555 or measured those currents "in real life", so I'm curious if
that is a real difference, or perhaps the bipolar 555 models don't model
it effectively?

On 03/18/2011 09:46 PM, Bitrex wrote:


Thanks for taking the time to create this model. I was doing some
experimenting with it and comparing it to the standard bipolar 555
model, and noticed that the CMOS model seems to have significantly
greater shoot-through current than the bipolar model. I haven't used a
CMOS 555 or measured those currents "in real life", so I'm curious if
that is a real difference, or perhaps the bipolar 555 models don't model
it effectively?

Can't say about this specific family, but we had a HORRIBLE experience
last year with a recent 5 V single-gate part, in the 74LVC1G family.
We had a pair of analog comparators and a gate and FF from this family
in each channel of a circuit, packing 32 channels per 6-layer board. We
tried all SORTS of schemes to isolate the triggering of one channel from
others. Eventually, I thought to try measuring the shoot-through pulses
of the parts. I measured them as a complete channel, so it was one gate
PLUS one FF. I was able to estimate the shoot-through current at 2 A
for about 2 ns! Yikes, 2 AMPS!!! No WONDER it was crapping up the
analog section.

So, I started scanning data sheets for low equivalent switching
capacitance, and found some 3.3 V parts that showed much lower equiv
capacitance. That was the 74AUP1G family. I had to use 3 parts to get
the gating configuration I needed, and re-design the whole board to run
off 3.3 V instead of 5 V, but in the end it was a much cleaner board, as
well as fixing the inter-channel interference problem. These chips are
so quiet I can't really measure the shoot-through pulse. With the
others, I observed a substantial Voltage dip in the local decoupling caps.

I kind of think the 74LVC1G parts had some really crummy design, and
made no effort whatsoever to control the turn-on and turn-off times of
the output stage transistors, just had one driver stage feeding both P-
and N-channel devices. My guess is that the 74AUP1G parts have separate
drivers for the P- and N-channel output transistors and have some R-C
tweaking via sizing the drivers so that they can tune the turn-on and
turn-off precisely to get rid of shoot-through.

I was astounded at 2 A shoot-throughs, and can imagine this could bite
even a purely digital design, even if only in the EMI compliance area.
Man, a 2 A pulse at some clock frequency could really turn into a major
transmitter!

Jon

On Fri, 18 Mar 2011 22:46:48 -0400, Bitrex
wrote:

On 3/18/2011 7:13 PM, Jim Thompson wrote:
Got annoyed at the flaky 555 models that are out there, so I rolled my
own...

http://www.analog-innovations.com/SED/MyLMC555.zip

Based on old AMI 20V CMOS device models, mostly form/fit/function with
CMOS, but some behavioral on the front-end where it doesn't matter.

Optimized and fitted to National LMC555 at 5V operation. It'll work
at other voltages but may sink/source more or less than spec at other
voltages because of ancient 5u devices :-)

Try it out and let me know.

...Jim Thompson

Hi Jim,

Thanks for taking the time to create this model. I was doing some
experimenting with it and comparing it to the standard bipolar 555
model, and noticed that the CMOS model seems to have significantly
greater shoot-through current than the bipolar model. I haven't used a
CMOS 555 or measured those currents "in real life", so I'm curious if
that is a real difference, or perhaps the bipolar 555 models don't model
it effectively?

---
Notice that the shoot-through current for an ICM7555, in real life, as
indicated on page 6 of:

http://datasheets.maxim-ic.com/en/ds...55-ICM7556.pdf

is very small compared to that from the bipolar 555, so there's either
something wrong with Jim's model, or you're making an error of some
kind.

---
JF

On Tue, 22 Mar 2011 17:01:45 -0500, John Fields
wrote:

On Fri, 18 Mar 2011 22:46:48 -0400, Bitrex
wrote:

On 3/18/2011 7:13 PM, Jim Thompson wrote:
Got annoyed at the flaky 555 models that are out there, so I rolled my
own...

http://www.analog-innovations.com/SED/MyLMC555.zip

Based on old AMI 20V CMOS device models, mostly form/fit/function with
CMOS, but some behavioral on the front-end where it doesn't matter.

Optimized and fitted to National LMC555 at 5V operation. It'll work
at other voltages but may sink/source more or less than spec at other
voltages because of ancient 5u devices :-)

Try it out and let me know.

...Jim Thompson

Hi Jim,

Thanks for taking the time to create this model. I was doing some
experimenting with it and comparing it to the standard bipolar 555
model, and noticed that the CMOS model seems to have significantly
greater shoot-through current than the bipolar model. I haven't used a
CMOS 555 or measured those currents "in real life", so I'm curious if
that is a real difference, or perhaps the bipolar 555 models don't model
it effectively?

---
Notice that the shoot-through current for an ICM7555, in real life, as
indicated on page 6 of:

http://datasheets.maxim-ic.com/en/ds...55-ICM7556.pdf

is very small compared to that from the bipolar 555, so there's either
something wrong with Jim's model, or you're making an error of some
kind.

---
JF

I sized my CMOS devices based on source and sink current of the output
at VCC=+5V for the _LMC555_ chip... Intersil datasheet was used only
for structural ideas.

I simulate 7-8mA "shoot-thru" depending on direction of transition.
Which, for CMOS with considerable source sink capability, seems pretty
normal to me. Width at the 50% point of overlap current is 8.5ns,
TF/TR at output ~ 7.3ns

What does "...significantly greater shoot-through current than the
bipolar model" mean?

...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 | |
| Voice480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |

Remember: Once you go over the hill, you pick up speed

On 3/22/2011 7:01 PM, Jim Thompson wrote:
On Tue, 22 Mar 2011 17:01:45 -0500, John Fields
wrote:

On Fri, 18 Mar 2011 22:46:48 -0400, Bitrex
wrote:

On 3/18/2011 7:13 PM, Jim Thompson wrote:
Got annoyed at the flaky 555 models that are out there, so I rolled my
own...

http://www.analog-innovations.com/SED/MyLMC555.zip

Based on old AMI 20V CMOS device models, mostly form/fit/function with
CMOS, but some behavioral on the front-end where it doesn't matter.

Optimized and fitted to National LMC555 at 5V operation. It'll work
at other voltages but may sink/source more or less than spec at other
voltages because of ancient 5u devices :-)

Try it out and let me know.

...Jim Thompson

Hi Jim,

Thanks for taking the time to create this model. I was doing some
experimenting with it and comparing it to the standard bipolar 555
model, and noticed that the CMOS model seems to have significantly
greater shoot-through current than the bipolar model. I haven't used a
CMOS 555 or measured those currents "in real life", so I'm curious if
that is a real difference, or perhaps the bipolar 555 models don't model
it effectively?

---
Notice that the shoot-through current for an ICM7555, in real life, as
indicated on page 6 of:

http://datasheets.maxim-ic.com/en/ds...55-ICM7556.pdf

is very small compared to that from the bipolar 555, so there's either
something wrong with Jim's model, or you're making an error of some
kind.

---
JF

I sized my CMOS devices based on source and sink current of the output
at VCC=+5V for the _LMC555_ chip... Intersil datasheet was used only
for structural ideas.

I simulate 7-8mA "shoot-thru" depending on direction of transition.
Which, for CMOS with considerable source sink capability, seems pretty
normal to me. Width at the 50% point of overlap current is 8.5ns,
TF/TR at output ~ 7.3ns

What does "...significantly greater shoot-through current than the
bipolar model" mean?

...Jim Thompson

Sorry for the delay in my reply, I didn't realize the thread was still
active. Here's what I get using LTSpice with the test circuit:

http://i227.photobucket.com/albums/d...ex2007/555.jpg

The pulses appear to be about 100 ns wide. It probably is really better
than the bipolar 555, because looking at the graph on the Maxim
datasheet I don't believe the bipolar 555 model included with LTSpice is
modeling the supply spikes accurately.

On 3/24/2011 12:33 PM, Bitrex wrote:
On 3/22/2011 7:01 PM, Jim Thompson wrote:
On Tue, 22 Mar 2011 17:01:45 -0500, John Fields
wrote:

On Fri, 18 Mar 2011 22:46:48 -0400, Bitrex
wrote:

On 3/18/2011 7:13 PM, Jim Thompson wrote:
Got annoyed at the flaky 555 models that are out there, so I rolled my
own...

http://www.analog-innovations.com/SED/MyLMC555.zip

Based on old AMI 20V CMOS device models, mostly form/fit/function with
CMOS, but some behavioral on the front-end where it doesn't matter.

Optimized and fitted to National LMC555 at 5V operation. It'll work
at other voltages but may sink/source more or less than spec at other
voltages because of ancient 5u devices :-)

Try it out and let me know.

...Jim Thompson

Hi Jim,

Thanks for taking the time to create this model. I was doing some
experimenting with it and comparing it to the standard bipolar 555
model, and noticed that the CMOS model seems to have significantly
greater shoot-through current than the bipolar model. I haven't used a
CMOS 555 or measured those currents "in real life", so I'm curious if
that is a real difference, or perhaps the bipolar 555 models don't
model
it effectively?

---
Notice that the shoot-through current for an ICM7555, in real life, as
indicated on page 6 of:

http://datasheets.maxim-ic.com/en/ds...55-ICM7556.pdf

is very small compared to that from the bipolar 555, so there's either
something wrong with Jim's model, or you're making an error of some
kind.

---
JF

I sized my CMOS devices based on source and sink current of the output
at VCC=+5V for the _LMC555_ chip... Intersil datasheet was used only
for structural ideas.

I simulate 7-8mA "shoot-thru" depending on direction of transition.
Which, for CMOS with considerable source sink capability, seems pretty
normal to me. Width at the 50% point of overlap current is 8.5ns,
TF/TR at output ~ 7.3ns

What does "...significantly greater shoot-through current than the
bipolar model" mean?

...Jim Thompson

Sorry for the delay in my reply, I didn't realize the thread was still
active. Here's what I get using LTSpice with the test circuit:

http://i227.photobucket.com/albums/d...ex2007/555.jpg

The pulses appear to be about 100 ns wide. It probably is really better
than the bipolar 555, because looking at the graph on the Maxim
datasheet I don't believe the bipolar 555 model included with LTSpice is
modeling the supply spikes accurately.

My mistake, I think the pulses are shorter than that. It's a little
tricky measuring them in LTSpice.

On Thu, 24 Mar 2011 12:33:07 -0400, Bitrex
wrote:

..
..
..

I don't believe the bipolar 555 model included with LTSpice is
modeling the supply spikes accurately.

---
Here's the circuit I'm using to test Linear's NE555 model:

Version 4
SHEET 1 880 748
WIRE 224 192 -128 192
WIRE 544 192 448 192
WIRE -128 256 -128 192
WIRE -80 256 -128 256
WIRE 32 256 0 256
WIRE 64 256 32 256
WIRE 224 256 144 256
WIRE 512 256 448 256
WIRE 32 320 32 256
WIRE 176 320 32 320
WIRE 224 320 176 320
WIRE 608 320 448 320
WIRE 480 384 448 384
WIRE 608 416 608 320
WIRE 176 480 176 320
WIRE 512 480 512 256
WIRE 512 480 176 480
WIRE 544 496 544 192
WIRE -128 512 -128 256
WIRE 480 512 480 384
WIRE 480 512 -128 512
WIRE -128 528 -128 512
WIRE 176 544 176 480
WIRE -128 624 -128 608
WIRE 176 624 176 608
WIRE 176 624 -128 624
WIRE 544 624 544 576
WIRE 544 624 176 624
WIRE 608 624 608 496
WIRE 608 624 544 624
WIRE -128 688 -128 624
FLAG -128 688 0
SYMBOL Misc\\NE555 336 288 M0
SYMATTR InstName U1
SYMBOL voltage -128 512 M0
WINDOW 123 0 0 Left 0
WINDOW 39 0 0 Left 0
SYMATTR InstName V1
SYMATTR Value 5
SYMBOL res -96 240 M90
WINDOW 0 0 56 VBottom 0
WINDOW 3 32 58 VTop 0
SYMATTR InstName R1
SYMATTR Value 40k
SYMBOL res 48 240 M90
WINDOW 0 0 56 VBottom 0
WINDOW 3 32 56 VTop 0
SYMATTR InstName R2
SYMATTR Value 19.8k
SYMBOL res 624 400 M0
WINDOW 0 -45 40 Left 0
WINDOW 3 -59 71 Left 0
SYMATTR InstName R3
SYMATTR Value 1000
SYMBOL cap 192 544 M0
WINDOW 0 -33 32 Left 0
WINDOW 3 -39 58 Left 0
SYMATTR InstName C1
SYMATTR Value 1e-7
SYMBOL res 528 480 R0
SYMATTR InstName R4
SYMATTR Value 1
TEXT 88 656 Right 0 !.tran .1 startup uic
TEXT 456 176 Left 0 ;1
TEXT 456 240 Left 0 ;2
TEXT 456 304 Left 0 ;3
TEXT 456 360 Left 0 ;4
TEXT 200 368 Left 0 ;5
TEXT 200 304 Left 0 ;6
TEXT 200 240 Left 0 ;7
TEXT 200 176 Left 0 ;8


I've just posted a query to:

http://groups.yahoo.com/group/LTspice/

for clarification re. the accuracy of the model, and I'll post what
comes back as soon as I get it.

Maybe Helmut will post here first.

--
JF

On Thu, 24 Mar 2011 16:06:23 -0500, John Fields
wrote:

On Thu, 24 Mar 2011 12:33:07 -0400, Bitrex
wrote:

.
.
.

I don't believe the bipolar 555 model included with LTSpice is
modeling the supply spikes accurately.

---
Here's the circuit I'm using to test Linear's NE555 model:

Version 4
SHEET 1 880 748
WIRE 224 192 -128 192
WIRE 544 192 448 192
WIRE -128 256 -128 192
WIRE -80 256 -128 256
WIRE 32 256 0 256
WIRE 64 256 32 256
WIRE 224 256 144 256
WIRE 512 256 448 256
WIRE 32 320 32 256
WIRE 176 320 32 320
WIRE 224 320 176 320
WIRE 608 320 448 320
WIRE 480 384 448 384
WIRE 608 416 608 320
WIRE 176 480 176 320
WIRE 512 480 512 256
WIRE 512 480 176 480
WIRE 544 496 544 192
WIRE -128 512 -128 256
WIRE 480 512 480 384
WIRE 480 512 -128 512
WIRE -128 528 -128 512
WIRE 176 544 176 480
WIRE -128 624 -128 608
WIRE 176 624 176 608
WIRE 176 624 -128 624
WIRE 544 624 544 576
WIRE 544 624 176 624
WIRE 608 624 608 496
WIRE 608 624 544 624
WIRE -128 688 -128 624
FLAG -128 688 0
SYMBOL Misc\\NE555 336 288 M0
SYMATTR InstName U1
SYMBOL voltage -128 512 M0
WINDOW 123 0 0 Left 0
WINDOW 39 0 0 Left 0
SYMATTR InstName V1
SYMATTR Value 5
SYMBOL res -96 240 M90
WINDOW 0 0 56 VBottom 0
WINDOW 3 32 58 VTop 0
SYMATTR InstName R1
SYMATTR Value 40k
SYMBOL res 48 240 M90
WINDOW 0 0 56 VBottom 0
WINDOW 3 32 56 VTop 0
SYMATTR InstName R2
SYMATTR Value 19.8k
SYMBOL res 624 400 M0
WINDOW 0 -45 40 Left 0
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I've just posted a query to:

http://groups.yahoo.com/group/LTspice/

for clarification re. the accuracy of the model, and I'll post what
comes back as soon as I get it.

Maybe Helmut will post here first.

The NE555 model in LTspice is virtually all behavioral modeling. Just
a quick observation of the switches (6 Ohms) suggest a whopping spike
;-)

...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 | |
| Voice480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |

Remember: Once you go over the hill, you pick up speed

"John Fields" schrieb im Newsbeitrag
...
On Thu, 24 Mar 2011 12:33:07 -0400, Bitrex
wrote:
I don't believe the bipolar 555 model included with LTSpice is
modeling the supply spikes accurately.
....
I've just posted a query to:
http://groups.yahoo.com/group/LTspice/
for clarification re. the accuracy of the model, and I'll post what
comes back as soon as I get it.
Maybe Helmut will post here first.
--
JF


Hello John,

The NE555 in the Misc-folder of LTspice may be just a gift from Mike.
I guess he made it because so many people asked for a 555.
LTC doesn't have a 555. So we can't expect that Mike spends
time to tweak the model for shoot-through current.

I tried a little bit with a capacitive load. Adding 100pF
to the output has given a significant current peak in the
power supply (V-source). Maybe this is a reasonable workaround
if somebody wants it more realistic..

Best regards,
Helmut

On Thu, 24 Mar 2011 23:24:52 +0100, "Helmut Sennewald"
wrote:

"John Fields" schrieb im Newsbeitrag
.. .
On Thu, 24 Mar 2011 12:33:07 -0400, Bitrex
wrote:
I don't believe the bipolar 555 model included with LTSpice is
modeling the supply spikes accurately.
....
I've just posted a query to:
http://groups.yahoo.com/group/LTspice/
for clarification re. the accuracy of the model, and I'll post what
comes back as soon as I get it.
Maybe Helmut will post here first.
--
JF


Hello John,

The NE555 in the Misc-folder of LTspice may be just a gift from Mike.
I guess he made it because so many people asked for a 555.
LTC doesn't have a 555. So we can't expect that Mike spends
time to tweak the model for shoot-through current.

I tried a little bit with a capacitive load. Adding 100pF
to the output has given a significant current peak in the
power supply (V-source). Maybe this is a reasonable workaround
if somebody wants it more realistic..

Best regards,
Helmut

---
Hello Helmut,

As always, with you, reason prevails. :-)

Thank you for your advice.

--
JF

On Thu, 24 Mar 2011 23:24:52 +0100, "Helmut Sennewald"
wrote:

"John Fields" schrieb im Newsbeitrag
.. .
On Thu, 24 Mar 2011 12:33:07 -0400, Bitrex
wrote:
I don't believe the bipolar 555 model included with LTSpice is
modeling the supply spikes accurately.
....
I've just posted a query to:
http://groups.yahoo.com/group/LTspice/
for clarification re. the accuracy of the model, and I'll post what
comes back as soon as I get it.
Maybe Helmut will post here first.
--
JF


Hello John,

The NE555 in the Misc-folder of LTspice may be just a gift from Mike.
I guess he made it because so many people asked for a 555.
LTC doesn't have a 555. So we can't expect that Mike spends
time to tweak the model for shoot-through current.

I tried a little bit with a capacitive load. Adding 100pF
to the output has given a significant current peak in the
power supply (V-source). Maybe this is a reasonable workaround
if somebody wants it more realistic..

Best regards,
Helmut

---
Hello Helmut,

Thanks. :-)

--
JF