Everyone,
I am trying to simulate a circuit (using LTSpice) with a OPA349 from Burr-Brown: 1 microamp Iq, 70kHz GBW, CMOS rail-rail I/O, 1.8V-5.5 opamp. According to the datasheet
The OPA349 appears to misbehave in my circuit simulations, so I created a simple test circuit consisting of a simple unity gain inverter with 1 Meg input, feedback and load resistors.
With a 1 MEG load the opamp seems to go out of closed-loop at Vin
"Tom (at tomsweb.net)" schrieb im Newsbeitrag news: snipped-for-privacy@o13g2000cwo.googlegroups.com...
Hello Tom, I tried the model with LTspice and see the same problem as you have described. I recommend you write a letter to AD.
Best regards, Helmut
"Helmut Sennewald" schrieb im Newsbeitrag news:dacf1r$uuv$03$ snipped-for-privacy@news.t-online.com...
Sorry, it's TI and not AD, Helmut
TI just confirmed that their model is crap (actually I would prefer them not offering a model at all in that case!).
--snip-- You were requesting the information about OPA349 Spice macro model. Our OPA349 macromodel is not a very good one. It was written 5 years ago and I've found that it does have some problems (Especially Low Voltage problems,less than 3Volts) .Sorry for the inconvenience caused.
You might want to consider using the TLV2401 device and the specifications are almost similar to OPA349. The TLV2401 device has a Spice model and it can be downloaded from TI website
--snip--
I'm now simulating with the TLV2401 model, which works. However, the real circuit will use a OPA349, because my supply is less than 2.5V (the minimum for TLV2401).
greetings, Tom
They (and others :) are not willing to spend the money it takes to derive a good model.
But that provokes a question to you... Would you PAY for a good model?
...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:(480)460-2142 | Brass Rat |
| http://www.analog-innovations.com | 1962 |
I love to cook with wine. Sometimes I even put it in the food.
I was inquiring to see if it were worthwhile to add model creation to my repertoire... they would not be of "unknown quality" ;-)
But I doubt anyone would pay.
I have had occasional RFQ's from AD, but they always go with the low bidder ;-)
...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:(480)460-2142 | Brass Rat |
| http://www.analog-innovations.com | 1962 |
I love to cook with wine. Sometimes I even put it in the food.
I would (and have, with lots of lost time making and vetting my own, that is). But before laying out my cash I'd want to see some documentation that it was good enough for my needs - sort of a spice- model datasheet with specs and plots.
I wouldn't want to pay thousdands of dollars.
--
Thanks,
- Win
"Tom (at tomsweb.net)" schrieb im Newsbeitrag news: snipped-for-privacy@o13g2000cwo.googlegroups.com...
Hello Tom,
thanks for this information. I will keep this message in my folder.
It sounds like TI will not spend any money/time to correct this model. What a bad service to their customers when I assume that they eventually know since 5 years that the model is wrong.
Best regards, Helmut
"Jim Thompson" schrieb im Newsbeitrag news: snipped-for-privacy@4ax.com...
Hello Jim,
I expect for standard parts that the manufacturer provides the model. If not then I would firstly try to make my own model before I spend money for unknown quality.
Best regards, Helmut
ElectronDepot website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.