LM1117 model

Feb 28, 2017 5 Replies

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If I download the "LM1117 Adjustable Unencrypted PSpice Transient Model", how do I use that in LT Spice? If I plop the file in the current sim folder, and .LIB name it on the schematic, how do I create a corresponding schematic symbol?



I want to see how it behaves with various load capacitors, like a polymer aluminum in parallel with a lot of ceramic bypasses.



I suppose I could breadboard it.



John Larkin Highland Technology, Inc picosecond timing precision measurement jlarkin att highlandtechnology dott com http://www.highlandtechnology.com

Search the LTSpice help for adding a model. It's not difficult, but I always wind up re-reading the help to set it up.

Just plop the Model as Text in the schematic and configure the parameters on the symbol. Or you can add it via the LIB file.

Cheers

Where do I get the schematic symbol from? The LT SPice HELP often isn't very helpful.

There is a native LT1117 in LT Spice, but I'm not sure it behaves the same as the LM1117. Neither is very specific about load impedances.

The LT1117 isn't happy with a polymer cap load; the ESR is too low.

John Larkin Highland Technology, Inc lunatic fringe electronics

Here's a 5 minute video:

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More expeditiously, you can automagically create a generic 'box' symbol as in this link

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  1. Open the netlist file that contains the subcircuit definitions in LTspice (File > Open or drag file into LTspice)
  2. Right-click the line containing the name of the subcircuit, and select Create Symbol:
Best regards, Spehro Pefhany

Change could, to should.

Thanks, - Win

Yep. I wouldn't count on it properly modeling capacitive loading. ...Jim Thompson

-- | James E.Thompson | mens | | Analog Innovations | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | STV, Queen Creek, AZ 85142 Skype: skypeanalog | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at

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