LM25576 Reference Design 6-42V input, 5V 3A output
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This LM25576 reference design is based on a LM25576 demonstration board which was a assembled and tested platform to evaluate the LM25576 SIMPLE SWITCHER® step-down converter. The reference design takes a 6V-42V input and generates a regulated 5V output that can source up to 3A of current.
The primary consideration for this design was to obtain the highest efficiency LM25576 design, over it’s full operating voltage input range. Cost and size of components were a secondary consideration (i.e.: using small, less expensive ceramic capacitors; a small, off the shelf inductor; etc.). The result is a design that achieves 95% peak efficiency, with a short list of necessary components. All optional features of the LM25576 can be enabled if necessary. The board layout is ideal for demonstrating the capabilities of the target design, while allowing for easy probing and adjustments.
The LM25576 is an easy to use Simple Switcher buck regulator which allows design engineers to design and optimize a robust power supply using a minimum set of components. Operating with an input voltage range of 6 - 42V, the LM25576 delivers 3A of continuous output current with an integrated 170 mΩ N-Channel MOSFET. The regulator utilizes an Emulated Current Mode architecture which provides inherent line regulation, tight load transient response, and ease of loop compensation without the usual limitation on low-duty cycles associated with current mode regulators. The operating frequency is adjustable from 50 kHz to 1 MHz to allow optimization of size and efficiency. To reduce EMI, a frequency synchronization pin allows multiple IC’s from the LM2557x family to self-synchronize or to synchronize to an external clock. The LM25576 guarantees robustness with cycle-by-cycle current limit, short-circuit protection, thermal shut-down, and remote shut-down. The device is available in a power enhanced TSSOP-20 package featuring an exposed die attach pad for thermal dissipation.
The LM25576 is supported by the full suite of WEBENCH® On-Line design tools
- Board Gerbers
- Orcad Board Layout
- Bill of Materials (Excel)
- Board Layouts (pdf)
- Orcad Schematic
- Board Electrical Measurements
- SIMPLE SWITCHER® regulator
- 6-42V input operation
- Synchronizeable switching frequency
- Regulated 5V output at up to 3A
- 300 kHz switching frequency
- Easily adjustable output voltage down to 1.225V
- 95% maximum efficiency
- On-board shutdown circuitry
- Also demonstrates LM5576
- Integrated WEBENCH design
- RoHS compliant
- Design was assembled and tested
- Step-down 36V, 24V, or 12V rail to regulated 5V output
- Robust, industrial power supply
- Automotive applications
- White goods power supplies