1 Introduction

This evaluation board describes the LM2745/LM2748 printed circuit board (PCB) design and provides an example typical application circuit. The demo board allows component design flexibility in order to demonstrate the versatility of the LM2745/LM2748 IC.

The demo board contains a voltage-mode, high-speed synchronous buck regulator controller. Though the control sections of the IC are rated for 3 V to 6 V (V_CC), the driver sections are designed to accept input supply rails (V_IN) as high as 14 V.

The demo board design regulates to an output voltage of 1.2 V at 3.5A with a switching frequency of 1 MHz from a 1-MHz clock source that has an amplitude from 0 V to V_CC. Note, the demo board is optimized for a 1-MHz, 14-V input voltage compensation design with V_CC = 3.3 V. If a slower switching frequency and input voltage is desired, consult the device-specific data sheet for control loop compensation procedures. For additional design modifications, see the Design Consideration section of the LM2745/8 Synchronous Buck Controller with Pre-bias Startup, and Optional Clock Synchronization Data Sheet.

The demo board accommodates the use of banana clips to clip onto pads on the board. If preferred, the pads inner diameters are 100 mils, for which a solder terminal can be placed (Newark 40F6004). The PCB is designed on two layers with 1-oz. copper on a 62-mil FR4 laminate.