EN5312QI 查看數據表（PDF） - Enpirion, Inc.

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EN5312QI

1A Synchronous Buck Regulator With Integrated Inductor

Enpirion, Inc. 

March 2007

Detailed Description

Functional Overview

The EN5312QI is a complete DCDC converter

solution requiring only two low cost MLCC

capacitors.

MOSFET switches, PWM

controller, Gate-drive, compensation, and

inductor are integrated into the tiny 5mm x

4mm x 1.1mm package to provide the smallest

footprint possible while maintaining high

efficiency, low ripple, and high performance.

The converter uses voltage mode control to

provide the simplest implementation and high

noise immunity. The device operates at a high

switching frequency. The high switching

frequency allows for a wide control loop

bandwidth providing excellent transient

performance. The high switching frequency

enables the use of very small components

making possible this unprecedented level of

integration.

Enpirion’s proprietary power MOSFET

technology provides very low switching loss at

frequencies of 4 MHz and higher, allowing for

the use of very small internal components, and

very wide control loop bandwidth. Unique

magnetic design allows for integration of the

inductor into the very low profile 1.1mm

package. Integration of the inductor virtually

eliminates the design/layout issues normally

associated with switch-mode DCDC

converters. All of this enables much easier

and faster integration into various applications

to meet demanding EMI requirements.

Output voltage is chosen from seven preset

values via a three pin VID voltage select

scheme. An external divider option enables

the selection of any voltage in the 0.6V to VIN-

0.6V range. This reduces the number of

components that must be qualified and

reduces inventory burden. The VID pins can

be toggled on the fly to implement glitch free

dynamic voltage scaling.

Protection features include under-voltage lock-

out (UVLO), over-current protection (OCP),

EN5312QI

short circuit protection, and thermal overload

protection.

Integrated Inductor

Enpirion has introduced the world’s first

product family featuring integrated inductors.

The EN5312QI utilizes a low loss, planar

construction inductor. The use of an internal

inductor localizes the noises associated with

the output loop currents. The inherent shielding

and compact construction of the integrated

inductor reduces the radiated noise that

couples into the traces of the circuit board.

Further, the package layout is optimized to

reduce the electrical path length for the AC

ripple currents that are a major source of

radiated emissions from DCDC converters.

The integrated inductor significantly reduces

parasitic effects that can harm loop stability,

and makes layout very simple.

Soft Start

Internal soft start circuits limit in-rush current

when the device starts up from a power down

condition or when the “ENABLE” pin is

asserted “high”. Digital control circuitry limits

the VOUT ramp rate to levels that are safe for

the Power MOSFETS and the integrated

inductor. The soft start ramp rate is nominally

1.65V/mS.

Over Current/Short Circuit Protection

The current limit function is achieved by

sensing the current flowing through a sense P-

MOSFET which is compared to a reference

current. When this level is exceeded the P-

FET is turned off and the N-FET is turned on,

pulling VOUT low. This condition is maintained

for a period of 1mS and then a normal soft start

is initiated. If the over current condition still

persists, this cycle will repeat in a “hick-up”

mode.

©Enpirion 2007 all rights reserved, E&OE

7

www.enpirion.com

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