Description

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.Design TargetsThe 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.Product DescriptionThe 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