[sdiy] Modelling the LM13700 bias input in LTSpice

Tim Stinchcombe tim102 at timstinchcombe.co.uk
Sun Aug 13 19:38:27 CEST 2017

Hi Tom,
	There are two decent-ish SPICE models for the LM13700 out there - the original National Instruments one should be this one from TI linked here (I've not unzipped it to check):


There is also a component-level model by the guy intimately related with the chip (the designer?):


However in both cases you will need to know how to import a standard SPICE sub-circuit into LTspice, and then create and associate a circuit symbol with it!

In both cases the voltage at the Iabc should look like two diode drops above the negative rail.

Tim Stinchcombe 

Cheltenham, Glos, UK
email: tim102 at timstinchcombe.co.uk

> -----Original Message-----
> From: Synth-diy [mailto:synth-diy-bounces at synth-diy.org] On Behalf Of Tom
> Wiltshire
> Sent: 13 August 2017 11:29
> To: SYNTH DIY <Synth-diy at synth-diy.org>
> Subject: [sdiy] Modelling the LM13700 bias input in LTSpice
> Hi All,
> If I want to do some experiments in simulation, using different current sources to
> feed the pin1/16 bias input of the LM13700, how should I model the 13700’s input?
> I don’t particularly need to model the whole chip, but I need the input to respond
> realistically. If modelling the whole chip is the best way, where do I find a good
> LM!34700 model? I’ve read various places that the input is two diode drops above
> the negative power rail, and other places that it’s a diode drop above ground. And
> what about its impedance? What does that look like?
> Thanks,
> Tom
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