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User's Guide
SNVA459A–January 2011–Revised April 2013
AN-2089 LMZ14203H/02H/01H Evaluation Board
1 Introduction
The LMZ14203H/02H/01H SIMPLE SWITCHER® power modules for high output voltage are easy-to-use
DC-DC solutions capable of driving up to a 3A load with exceptional power conversion efficiency, output
voltage accuracy, line and load regulation. They are available in an innovative package that enhances
thermal performance and allows for hand or machine soldering.
The LMZ14203H/02H/01H Evaluation Board is configured for 12V output voltage from 15V to 42V input.
The precision enable input allows for programmable UVLO of the input supply. The resistor voltage divider
R
ENT
and R
ENB
set the input UVLO threshold. Connect the V
IN
turret terminal to the EN turret on the board
to enable operation.
The external soft-start capacitor C
SS
facilitates controlled startup output rise time. The resistors R
FBT
and
R
FBB
set the output voltage. An output feed-forward capacitor C
FF
across the upper feedback resistor trims
for optimum transient response. The control loop operates well with low ESR output capacitors such as
ceramic and polymer electrolytic capacitors. The resistor R
ON
sets the operating frequency. See datasheet
for component selection details.
The LMZ14203H/02H/01H PCB layout offers excellent thermal performance, achieving junction-to-ambient
thermal resistance θ
JA
of 14.9°C/W. The evaluation board with its default Bill of Materials offers great EMI
performance, complying with the EN 55022 Class B radiated emissions standard. The solution also
complies with the CISPR22 conducted emissions standard with the addition of a small input filter.
2 Board Specifications
• V
IN
= 15V to 42V
• V
OUT
= 12V
• 3A max load at 24V
IN
and 65°C T
AMB
• Low radiated EMI (EN 55022 Class B compliant)
• 400kHz switching frequency
• Enable UVLO set at 13.5V
• θ
JA
= 14.9°C/W
• 4 copper layers
• 2 oz copper on top and bottom layer
• 1 oz copper on internal layers
• 6.985 cm x 7.620 cm (2.75 in x 3 in) with 1.575 cm (.062 in) thickness of FR4 laminate material
3 Additional Footprints
Additional component mounting pads are available to experiment with alternative input and output
capacitor combinations or a zener clamp on the enable input. See Figure 6 for corresponding schematic
locations.
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1
SNVA459A–January 2011–Revised April 2013 AN-2089 LMZ14203H/02H/01H Evaluation Board
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