LINEAR LTspice IV User's Manual and Quick Reference Guide (1)

What’s New with LTspice IV? Gabino Alonso

Follow @LTspice on Twitter for

up-to-date information on models, demo circuits, events and user tips: www.twitter.com/LTspice

NEW HOW-TO VIDEOS Adding Third-Party Models to LTspice IV • LTM8047: 3.1V to 32V isolated µModule video.linear.com/97

Using Transformers in LTspice® IV DC/DC converter www.linear.com/8047

LTspice IV includes models for many dis-

video.linear.com/93

Switching Regulators

crete components, such as transistors and

Transformers and coupled inductors

• LTC3765: Active clamp forward controller

MOSFETs, but many component manufac-

are key components in many switch-

and gate driver www.linear.com/3765

turers make additional models that you

ing regulator designs, including flyback,

can add to your LTspice IV circuit simula- • LTC3766: High efficiency, second-

forward and SEPIC converters. Although

tions. These third-party SPICE models are ary-side synchronous forward

it is possible to make a dedicated subcir-

described in .MODEL and .SUBCKT state- controller www.linear.com/3766

cuit for a specific transformer, it is often

ments. This video provides an overview of

better in LTspice IV to define a separate • LT®3759: Wide input voltage range

how to add a third-party .MODEL state-

inductor for each transformer winding, boost/SEPIC/inverting controller

ment for an intrinsic SPICE device and

and then couple them all together mag- www.linear.com/3759

how to add and create a symbol for

netically via a single mutual inductance

• LTC3536: 1A low noise, buck-boost

a third party .SUBCKT statement.

(K) statement. This video shows how to

DC/DC converter www.linear.com/3536

define a transformer using inductors and

NEW LTspice DEVICE

• LT3507A: Triple monolithic step-down reg-

specify the mutual inductance via a single MACRO MODELS

ulator with LDO www.linear.com/3507A

K statement in your LTspice IV simulations. To update your installation of

LTspice IV with the latest models, choose Linear Regulators

Two new LTspice IV how-to videos are now available

Sync Release from the Tools menu. You • LT3015: 1.5A, low noise, nega-

Transformers

can review the changelog.txt after Sync tive linear regulator with precision Release for the complete list of new mod- current limit www.linear.com/3015

3rd-Party Models els. Here is a list of some new models:

Amplifiers & Comparators µModule Regulators • LT6108: High side current sense What is LTspice IV? • LTM8048: 3.1V to 32V input isolated amplifier with reference and µModule DC/DC converter with LDO post comparator www.linear.com/6108

LTspice® IV is a high performance SPICE

regulator www.linear.com/8048

simulator, schematic capture and waveform • LTC6360: Very low noise single-

viewer specifically designed to speed up the

ended SAR ADC driver with true zero

process of power supply design. LTspice IV

output www.linear.com/6360

adds enhancements and models to SPICE, significantly reducing simulation time compared to typical SPICE simulators, allowing one to view waveforms for most switching regulators

in minutes compared to hours for other SPICE simulators.

SW1 SW2 VOUT

VIN VOUT 3.3V

LTspice IV is available free from Linear 1.8V TO 5.5V

47p F 1A FOR VIN ≥ 3V

Technology at www.linear.com/LTspice. Included LTC3536

6.49k in the download is a complete working version of 1000k

PWM BURST MODE/SYNC FB

LTspice IV, macro models for Linear Technology’s 220p F Download the LTspice IV

10µF OFF ON SHDN 22µF

power products, over 200 op amp models, as RT VC demonstration circuit for this

well as models for resistors, transistors and PGND SGND 1A low noise, buck-boost

MOSFETs. DC/DC converter at www. linear.com/3536

26 | January 2012 : LT Journal of Analog Innovation