User's Guide
SNVA248 – October 2007
AN-1646 LM3102 Demonstration Board Reference Design
1
Introduction
The LM3102 Step Down Switching Regulator features all required functions to implement a cost effective,
efficient buck power converter capable of supplying 2.5A to loads. The Constant On-Time (COT)
regulation scheme requires no loop compensation, results in a fast load transient response and simple
circuit implementation that allows a low component count, and consequently very small overall board
space is required for a typical application. The regulator can function properly even with an all ceramic
output capacitor network, and does not rely on the output capacitor’s ESR for stability. The operating
frequency remains constant with line variations due to the inverse relationship between the input voltage
and the on-time. Protection features include output over-voltage protection, thermal shutdown, V
CC
under-
voltage lock-out, gate drive under-voltage lock-out. The LM3102 is available in the thermally enhanced
eTSSOP-20 package.
This user's guide details the design of a demonstration board which provides a 3.3V output voltage with
2.5A load capability for a wide input voltage range from 8V to 42V. The demonstration board schematic,
PCB layout, Bill of Materials, and circuit design descriptions are shown. Typical performance and
operating waveforms are also provided for reference.
2
Demonstration Board Schematic
Figure 1. LM3102 Demonstration Board Schematic
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1
SNVA248 – October 2007
AN-1646 LM3102 Demonstration Board Reference Design
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