April 2012

Doc ID 10209 Rev 4

1/30

AN1882

Application note

Designing with the L6926, high efficiency monolithic

synchronous step-down regulator

Introduction

This application note details the main features and application advantages of this new

synchronous step-down regulator. After describing how the device works and the main

features, a step-by-step design section is provided in order to aid in the selection of the

external components and in the evaluation of the losses. The device performances are

shown in terms of efficiency and thermal results. At the end, some application ideas are

proposed. This new product, designed using BCDV technology, is a high efficiency

monolithic synchronous step-down regulator capable of delivering up to 800 mA of

the 100% duty cycle operation capability. The input voltage ranges from 2 V to 5.5 V. The

control loop architecture is based on a constant frequency peak current mode, while high

efficiency at light loads is achieved by a low consumption functionality. The very low

quiescent current (25 µA) and shutdown current (0.2 µA) make the device very suitable to

supply battery-powered equipment like PDAs and hand-held terminals, DSCs (digital still

cameras) and cellular phones. The switching frequency is internally set at 600 kHz, but the

device can be externally synchronized up to 1.4 MHz. An internal reference voltage of 0.6 V

(typ) allows the device to regulate a minimum output voltage of the same low value. The low

features are: hysteretic UVLO, OVP, constant current short-circuit protection, Power Good

and thermal shutdown. The MSOP8 package allows significant space savings on the board.

Figure 1.

Application test circuit

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