34726 datasheet(10/19 Pages) FREESCALE

10 / 19 page

Analog Integrated Circuit Device Data

Freescale Semiconductor

34726

FUNCTIONAL DESCRIPTION

INTRODUCTION

FUNCTIONAL DESCRIPTION

INTRODUCTION

The 34726 is a high efficiency, synchronous, buck

regulator, utilizing a voltage mode control architecture with

feed forward. It is capable of providing a 300mA load current

for output voltages of 0.8V to 3.3V, from a single input voltage

rail between 2.7V and 5.5V.

In a buck converter, most of the losses at high output loads

are due to conduction losses in the power train, but at light

output loads, the conduction losses are reduced and most of

the losses become switching losses. Using Freescale’s Z-

mode architecture, the 34726, at light output loads, will

smoothly transition into a lower switching frequency, thus

improving its efficiency.

FUNCTIONAL PIN DESCRIPTION

SUPPLY VOLTAGE INPUT (VIN)

2.7V to 5.5V DC power input. Bypass with a 4.7

µF ceramic

capacitor as close as possible to the VIN and GND pins.

GROUND (GND)

Ground.

ENABLE (EN)

Active high enable input. EN is over-voltage protected to

6.0V, independent of the supply voltage. Drive with a logic

high signal (or connect to VIN) for normal operation. Drive

with a logic low signal, or connect to GND will disable the

34726.

FEEDBACK INPUT (FB)

Feedback of the output voltage.

SWITCHING NODE (SW)

This terminal connects to the output inductor. The node

internally connects the drain of both high side MOSFET and

low side MOSFET.

NO CONNECTION (NC)

Internally not connected. Connect to GND externally.

34726 Datasheet(PDF) 10 Page - Freescale Semiconductor, Inc