03799

11/24/2009

Rev:B

*Optimized PCB Layout file downloadable from the Enpirion Website to assure first pass design success.

EN5311QI

1A Synchronous Buck Regulator

With Integrated Inductor

RoHS Compliant

Halogen Free

Featuring Integrated Inductor Technology

Voltage

Select

DAC

Switch

VREF

(+)

(-)

Error

Amp

V

SENSE

V

FB

V

OUT

VS0 VS1 VS2

Package Boundry

P-Drive

N-Drive

UVLO

Thermal Limit

Current Limit

Soft Start

Sawtooth

Generator

(+)

(-)

PWM

Comp

V

IN

ENABLE

GND

Logic

Compensation

Network

Product Highlights

• Revolutionary Integrated Inductor

• 5mm x 4mm x1.1mm QFN package

• Very small total solution foot print*

• 4 MHz switching frequency

• Only two low cost MLCC caps required

• Designed for low noise/low EMI

• High efficiency, up to 95%

• Wide 2.4V to 6.6V input range

• 1000mA continuous output current

• Less than 1 μA standby current.

• Excellent transient performance

• 3 Pin VID Output Voltage select

• 100% duty cycle capable

• Short circuit and over current protection

• UVLO and thermal protection

• RoHS compliant; MSL 3 260°C reflow

Product Overview

The Ultra-Low-Profile EN5311QI is targeted to

applications where board area and profile are

critical. EN5311QI is a complete power

conversion solution requiring only two low cost

ceramic MLCC caps.

Inductor, MOSFETS,

PWM, and compensation are integrated into a

tiny 5mm x 4mm x 1.1mm QFN package. The

EN5311QI is engineered to simplify design and

to minimize layout constraints.

4 MHz

switching frequency and internal type III

compensation

provides

superior

transient

response.

With a 1.1 mm profile, the

EN5311QI is ideal for space and height

constrained applications.

A 3-pin VID output voltage selector provides

seven pre-programmed output voltages along

with an option for external resistor divider.

Output voltage can be programmed on-the-fly

to provide fast, dynamic voltage scaling.

Typical Application Circuit

10

μF

4.7

μF

GND

ENABLE

Voltage

Select

Figure 1. Typical application circuit.

Applications

• Area constrained applications

• Noise Sensitive Applications such as A/V

and RF

• LDO replacement for improved thermals

• Set top box/home gateway

• Smart phones, PDAs

• VoIP and Video phones

• Personal Media Players