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User's Guide
SNVA422E–January 2010–Revised April 2013
AN-2024 LMZ1420x / LMZ1200x Evaluation Board
1 Introduction
The LMZ1420x and LMZ1200x SIMPLE SWITCHER
®
power modules are easy-to-use DC-DC solution
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 LMZ14203/2/1 can accept an input voltage rail between 6V and 42V and the LMZ12003/2/1 can
accept an input voltage rail between 4.5V and 20V. The devices can deliver an adjustable and highly
accurate output voltage as low as 0.8V and as high as 6V. The control structure is constant on-time with
input voltage feed forward. This creates a nearly constant switching frequency across the input voltage
range. The control loop operates well with low ESR output capacitors such as ceramics. An output feed-
forward capacitor across the upper feedback resistor trims for optimum transient response. The precision
enable input allows for programmable UVLO of the input supply. The external soft-start capacitor
facilitates controlled startup output rise time. The LMZ1420x and LMZ1200x family is a reliable and robust
solution with the following features: lossless cycle-by-cycle valley current limit to protect for over current or
short-circuit fault, thermal shutdown, input under-voltage lock-out, and will start up into a pre-biased
output.
2 Board Specifications
• LMZ1420x V
IN
= 6V to 42V
• LMZ1420x enable UVLO = 8V
• LMZ1420x V
OUT
= 3.3V
• LMZ1200x V
IN
= 4.5V to 20V
• LMZ1200x enable UVLO = 4.5V
• LMZ1200x V
OUT
= 1.8V
• Operates at full load up to 80°C ambient at 12V input
• θ
JA
= 20°C / W, θ
JC
= 1.9°C / W
• Designed on four layers, all four layers are 1 oz. copper weight
• The two internal ground planes are identical
• Measures 1.705 in. x 3.03 in. (4.33 cm x 7.7cm) and is 62mil (.062”) thick of FR4 laminate material
For additional circuit modifications see the Design Consideration section in the device-specific data sheet.
For negative output voltage connections, see AN-2027 Inverting Application for the LMZ14203 SIMPLE
SWITCHER® Power Module (SNVA425).
SIMPLE SWITCHER is a registered trademark of Texas Instruments.
All other trademarks are the property of their respective owners.
1
SNVA422E–January 2010–Revised April 2013 AN-2024 LMZ1420x / LMZ1200x Evaluation Board
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