"Real" SPICE model for sync buck chip anywhere?

Write your own ?:-)

I presume you're using an LT device? Where are you going to get device-level models for the output?

I do that sort of thing... for a fee ;-) ...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  |             |
| 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 might (have to) do that. I have designed semi-discrete switch mode converters, meaning sans commercial PWM chip. But they contain logic chips used in an unorthodox fashion for which there are no models. So I'd have to make models for those. Not exactly a fun job.

It doesn't matter. It's just a theoretical experiment, not for a client or something.

Some models (older Unitrode chips etc.) are 100% device-level so that would work. Except that even the timing stuff is device-level and then sim runs take forever. Because upon each time step it has to also slosh through 15-20 transistors in the RS flip flop, and another few hundred in housekeeping circuits. Big waste. Those sims made the office temp rise by several degrees. To my surprise one of our Labradors likes that and curls up by the PC like a giant cat.

I know :-)

Could pay in buckeye balls. But they are dwindling fast ...

--
Regards, Joerg

http://www.analogconsultants.com/

Let's narrow it down... you simply want a "buck core model" that you add pass device and flyback diode?? Synchronized? ...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  |             |
| 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.

Not synchronized but synchronous. Meaning a bottom FET instead of the diode. I think I am just going to start wit the LTC3810. It requires external FETs, one can get at the internally regulated voltage and I know its behoir because I've used it in real life. So I'd (hopefully) be able to concoct some sort of spoiler up front of the FB pin if needed.

--
Regards, Joerg

http://www.analogconsultants.com/

Whoops, I meant behavior. Maybe the 9 volts of the Belgian style ale yesterday was too much :-)

The fun starts at 2:30min.

--
Regards, Joerg

http://www.analogconsultants.com/

[snip]

Encrypted :-(

You don't like LT's model ?:-) ...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 | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at

| 1962 | I love to cook with wine. Sometimes I even put it in the food.

They all are :-(

Not really but one has to use what's there. It's largely behavioral. But I can crochet some stuff around it to make it less so.

--
Regards, Joerg

http://www.analogconsultants.com/

I bet they don't model this:

ftp://jjlarkin.lmi.net/SwitcherRise.JPG

This is the switch node of a National LM3102 synchronous switcher chip. It's a beautiful, classical step-recovery diode waveform, probably faster than my 500 MHz scope suggests. This freaked out opamps all over the board.

John