LT1028 works, but LT1028N, the one that brings out the comp pin, doesn't.
--
John Larkin Highland Technology Inc
Precision electronic instrumentation Picosecond-resolution Digital Delay and Pulse generators Custom timing and laser controllers Photonics and fiberoptic TTL data links VME analog, thermocouple, LVDT, synchro, tachometer Multichannel arbitrary waveform generators
I have LTspice v4.19s, which I think is the latest.
Searching the directory structure, I find neither an assembly (.ASY) or a model (.SUB, .LIB, or .MOD) for LT1028N. ...Jim Thompson
-- | James E.Thompson | mens | | Analog Innovations | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | San Tan Valley, AZ 85142 Skype: Contacts Only | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at
Checked sync release, now up to 4.19u, no LT1028N. ...Jim Thompson
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| James E.Thompson | mens |
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I love to cook with wine. Sometimes I even put it in the food.
It's in this library....
From the date of the library... is it an obsolete part? ...Jim Thompson
-- | James E.Thompson | mens | | Analog Innovations | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | San Tan Valley, AZ 85142 Skype: Contacts Only | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at
where have you found LT1028N? I can't find it int the latest version, and when looking at the linear site it doesn't even exist
-Lasse
Found it in this old library...
It's not in the latest version of ASY symbols. ...Jim Thompson
--
| James E.Thompson | mens |
| Analog Innovations | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
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| Voice:(480)460-2350 Fax: Available upon request | Brass Rat |
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I love to cook with wine. Sometimes I even put it in the food.
And the symbol here...
...Jim Thompson
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| James E.Thompson | mens |
| Analog Innovations | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
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| 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.
LT1028N symbol calls LTC.lib, but LT1028N isn't in there, only LT1028.
It's not in any of the other .lib files, either, according to grep.
Looks like they slipped up.
--
"Design is the reverse of analysis"
(R.D. Middlebrook)
Where did you find an LT1028N symbol? My v4.19u doesn't have it.
Methinks it's been dropped. Haven't found a datasheet. ...Jim Thompson
--
| James E.Thompson | mens |
| Analog Innovations | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| San Tan Valley, AZ 85142 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.
And searching the Linear website for LT1028N only returns LT1028. ...Jim Thompson
-- | James E.Thompson | mens | | Analog Innovations | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | San Tan Valley, AZ 85142 Skype: Contacts Only | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at
Found an old library file in my backup directory, with an LT1028 subcircuit. Looks like it's obsolete. D'you want the subcircuit?
--
"Design is the reverse of analysis"
(R.D. Middlebrook)
Probably the same way as me. I never sync versions, but install over the top. That way it doesn't screw up your existing, customized files, and backs up the ones that it does overwrite.
--
"Design is the reverse of analysis"
(R.D. Middlebrook)
I posted a link earlier.
Digging into the fine print of the LT1028 data sheet, an overcompensation pin (5 on the 8-pin packages), plus a couple graphs and some vague comments. Also two pins for VOS adjust.
Maybe _all_ LT1028's have the over-comp available? ...Jim Thompson
--
| James E.Thompson | mens |
| Analog Innovations | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| San Tan Valley, AZ 85142 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.
I meant to say that I have the original N-suffix subcircuit available.
--
"Design is the reverse of analysis"
(R.D. Middlebrook)
LT1028N Comp is pin 6
*CCM Tue May 19 15:37:45 1998 .SUBCKT LT1028N 1 2 3 4 5 6
--
"Design is the reverse of analysis"
(R.D. Middlebrook)
Mike tells me that the 1028N model wasn't accurate, so he deleted it. Part of the 1028N stuff was apparently still in my lib files, and in the opamp selection list. He suggested a resync, which didn't change things, so I did a full remove/reinstall, which *did* delete it.
The new 1028 model is supposed to be better, but it doesn't bring out the overcomp pin, which the 1028N model did, and I'd like to use.
I'd like to use the 1028 as a follower, and it's not stable that way. I figured I could tune the overcomp cap to make it stable and to make it really gain/phase flat to to a MHz or two, but I can't sim that now.
Most opamps, as followers, have a small gain peak before they roll off. Adding a RC lowpass downstream can tune that, at the expense of output impedance and one more part.
Life sucks.
-- John Larkin Highland Technology Inc www.highlandtechnology.com jlarkin at highlandtechnology dot com Precision electronic instrumentation Picosecond-resolution Digital Delay and Pulse generators Custom timing and laser controllers Photonics and fiberoptic TTL data links VME analog, thermocouple, LVDT, synchro, tachometer Multichannel arbitrary waveform generators
The 1028N model was a version of the 1028 model that brought out the overcomp pin. All physical LT1028s have that pin, but Spice doesn't support it any more.
-- John Larkin Highland Technology Inc www.highlandtechnology.com jlarkin at highlandtechnology dot com Precision electronic instrumentation Picosecond-resolution Digital Delay and Pulse generators Custom timing and laser controllers Photonics and fiberoptic TTL data links VME analog, thermocouple, LVDT, synchro, tachometer Multichannel arbitrary waveform generators
The LT1028 isn't the best option for a low noise op amp these days, except for special cases. It has a nasty noise and compensation whoopdedoo around 300 kHz that the data sheet doesn't come clean about (at least the one I have doesn't). How about a nice well behaved ADA4898 or ADA4899?
Cheers
Phil Hobbs
-- Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC Optics, Electro-optics, Photonics, Analog Electronics 160 North State Road #203 Briarcliff Manor NY 10510 USA +1 845 480 2058 hobbs at electrooptical dot net http://electrooptical.net
OK, thanks, I'll look at those.
-- John Larkin Highland Technology Inc www.highlandtechnology.com jlarkin at highlandtechnology dot com Precision electronic instrumentation Picosecond-resolution Digital Delay and Pulse generators Custom timing and laser controllers Photonics and fiberoptic TTL data links VME analog, thermocouple, LVDT, synchro, tachometer Multichannel arbitrary waveform generators
Comparing the datasheet, and the models, I find that the pinouts don't match, output on the wrong pin (5), should be 6.
Small signal transient response of the LT1028 model shows far too much overshoot, compared with datasheet waveform photograph, under stated conditions, and looks much more like LT1128.
Both using 10ns risetime test pulse.
I assume that the datasheet is authoritative. The real device looks much nicer than the model predicts.
Not what we've come to expect from LTC. At least they came clean.
--
"Design is the reverse of analysis"
(R.D. Middlebrook)
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