1 Introduction

The LM27342 demonstration board is designed to provide the power supply design engineer with a fully functional regulator design, which can be synchronized to an external clock between 1000 kHz and 2350 kHz. The evaluation board provides a 3.3-V output with a 2-A current capability. The wide input voltage ranges from 5 V to 20 V. Without an external synchronization signal, the design operates at 2000 kHz, reducing the solution size and keeping switching noise out of the AM radio band. The printed circuit board (PCB) consists of four layers of copper on FR4 material. There is a ground plane on the internal layer directly beneath the LM27342, and a ground plane on the bottom layer. The LM27342 is thermally tied to the ground planes by thermal vias directly underneath the device. The second internal layer is tied half to V_IN and half to V_OUT. This application report contains the evaluation board schematic, a quick setup procedure, and a bill-of-materials (BOM). For complete circuit design information, see the LM27341/LM27342/LM27341Q/LM27342Q 2 MHz 1.5A/2A Wide Input Range Step-Down DCDC Regulator with Frequency Synchronization data sheet.

The performance of the evaluation board is as follows:

• Input range: 5 V to 20 V
• Output voltage: 3.3 V
• Output current: 0 A to 2 A
• Frequency of operation: 1000 kHz to 2350 kHz
• Board size: 1.1 inches × 1.3 inches