LX1671CLQ-TR MICROSEMI [Microsemi Corporation], LX1671CLQ-TR Datasheet

LX1671CLQ-TR

Manufacturer Part Number

LX1671CLQ-TR

Description

Multiple Output LoadSHARE PWM

Manufacturer

MICROSEMI [Microsemi Corporation]

Datasheet

1.LX1671CLQ-TR.pdf (21 pages)

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Rev. 1.2b, 2006-02-13

power supply controller IC featuring

three PWM switching regulator stages

with an additional onboard linear

regulator driver.

voltage-mode PWM phases can be

easily configured for a single Bi-Phase

high current output or two in-

dependently regulated outputs. Each

phase

grammable soft-start sequence.

versatility yields either three or four

independently regulated outputs with

full power sequencing capability giving

system

flexibility in power supply design.

current (>30A) output can utilize

different supply rails allowing Forced

Current

sources. Power loss and noise, due to

the ESR of the input capacitors, are

minimized by operating each PWM

output 180° out of phase. This

architecture also minimizes capacitor

requirements while maximizing re-

gulator response.

IMPORTANT: For the most current data, consult MICROSEMI’s website: http://www.microsemi.com

LoadSHARE is a Trademark of Microsemi Corporation

Protected by US Patents: 6,285,571 & 6,292,378

The LX1671 is a highly integrated

Two of the constant frequency

In Bi-Phase operation, the high

incorporates

designers

Sharing

complete circuit.

Refer to Typical

Note: Available in Tape & Reel. Append the letters “TR” to the part number (i.e. LX1671CPW-TR)

Application for

0 to 70

†

3.3V

12V

(°C)

11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570

from

the

fully

D E S C R I P T I O N

RoHS Compliant / Pb-free Transition DC: 0518

different

LX1671

ultimate

This

pro-

Plastic TSSOP

38-Pin

supplying up to 5A (Linear Regulator

Driver) and 15A (Switching Regulator)

for I/O, memory, termination, and other

supplies surrounding today’s

processor designs.

programmed via a simple voltage-divider

network.

MOSFET R

current limit conditions, in each PWM

phase, without the use of expensive

current sense resistors.

design engineers maximum flexibility

with respect to the MOSFET supply.

Each phase can utilize different supply

voltages for efficient use of available

supply rails.

phases are configured in Bi-Phase output,

the LoadSHARE

programmed via inductor ESR selection.

There are three other methods that can

also be used with LoadSHARE

other methods are presented in the theory

of operation section of this data sheet.

Integrated Products, Power Management

LX1671CPW

The additional outputs are capable of

Each

The LX1671 was designed to give

Core

P R O D U C T H I G H L I G H T

PACKAGE ORDER INFO

PWM

Microsemi

DS(ON)

Controller

Graphics

The

Additionally, when two

I/O

regulator

impedance, monitors

LX1671,

topology can be

Multiple Output LoadSHARE™ PWM

DDR Termination

Memory Bus

output

....

utilizing

. These

RoHS Compliant / Pb-free Transition DC: 0512

micro-

RODUCTION

Plastic MLPQ

38-Pin

LX1671CLQ

DDR Memory

Up to Four Independently

Regulated Outputs

Outputs As Low As 0.8V

Generated From An Internal 1%

Reference

Multiphase High Current Output

Reduces Required Capacitance

Integrated High Current MOSFET

Drivers

300kHz High Frequency Operation

Minimizes External Component

Requirements

Independent Phase Programmable

Soft-Start and Power Sequencing

Adjustable Linear Regulator Driver

Output

No current-sense resistors

DDR Termination Compliant

Multi-Output Power Supplies

Video Card Power Supplies

PC Peripherals

Portable PC Processor and I/O

Supply

APPLICATIONS/BENEFITS

ATA

K E Y F E A T U R E S

Memory Core

HEET

LX1671

Page 1

Related parts for LX1671CLQ-TR

LX1671CLQ-TR Summary of contents

Page 1

... Minimizes External Component Requirements Independent Phase Programmable Soft-Start and Power Sequencing Adjustable Linear Regulator Driver Output No current-sense resistors DDR Termination Compliant APPLICATIONS/BENEFITS Multi-Output Power Supplies Video Card Power Supplies PC Peripherals Portable PC Processor and I/O Supply Memory Core DDR Memory Plastic MLPQ 38-Pin LX1671CLQ Page 1 ...

Page 2

Supply Voltage ( ................................................................-0.3V to 5.5V CC Supply Voltage (V ) Transient ......................................................-0.3V to 6.0V ...

Page 3

TM N AME Bi-Phase Operation: Phase 1 and 2 Voltage Feedback Single Phase Operation: Phase 1 Voltage Feedback , connect to the output through a resistor network to set FB1 desired output voltage of Phase 1 Error Amplifier Output – ...

Page 4

TM Unless otherwise specified, the following specifications apply over the operating ambient temperature 0°C otherwise noted and the following test conditions: V Parameter SWITCHING REGULATORS Input Voltage Operation Current Reference Voltage Line Regulation (Note 2) Load Regulation (Note 2) Minimum ...

Page 5

Unless otherwise specified, ...

Page 6

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TM CS2 CS Comp - + VS2 V I TRIP SET EO2 LPF2 Error Comp + - - FB2 + Amplifier/ Compensation V REF RF2 20k LPF1 P HASE1 SS/ENABLE CSS Figure 3 – Block Diagram of Phase 2 Connected ...

Page 8

TM +5V VOUT4 Figure 4 – Bi-Phase Operation With Phase 1 and 2 LoadSHARing From 12V and 5V (Phase 2 high-side MOSFET driver bootstrapped to 17V) Copyright © 2000 Rev. 1.2b, 2006-02-13 11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, ...

Page 9

TM LO1 PG1 LO2 H02 VC2 LDGD LDFB LDDIS DGND LX1671 AGN D RSVD SS2 RF2 FB2 EO2 CS2 VS2 SS1 FB1 Copyright © 2000 Rev. 1.2b, 2006-02-13 11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570 ® Multiple ...

Page 10

TM +3.3V +5V VOUT2 Figure 6 – Bi-Phase Operation With Phase 1 and 2 LoadSHARing From 3.3V and 5V Copyright © 2000 Rev. 1.2b, 2006-02-13 11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570 ® Multiple Output LoadSHARE™ PWM ...

Page 11

ENERAL ESCRIPTION The LX1671 is a voltage-mode pulse-width modulation controller integrated circuit. The internal ramp generator frequency is fixed to 300kHz. The device has external compensation, for more flexibility of output current magnitude (UVLO) ...

Page 12

SHARE (ESR M I HASE OAD ETHOD The first method is to change the ratio of the inductors ...

Page 13

L1, Switch Side 100 62k LPF1 Not Resistor Used Divider L2, Resistor Switch Side Divider LPF2 62k 62k 100 TBD 4700pF Where ...

Page 14

SHARE (P I HASE OAD ROPORTIONAL The best topology for generating a current ratio at full load and ...

Page 15

The circuit in Figure 9 sums a current through a 1MΩ ...

Page 16

UTPUT NDUCTOR The output inductor should be selected to meet the requirements of the output voltage ripple in steady-state operation and the inductor current slew-rate during transient. The peak-to- peak output voltage ripple is: = × V ...

Page 17

NPUT APACITOR The input capacitor and the input inductor, if used, are to filter the pulsating current generated by the buck converter to reduce interference to other circuits connected to the same 5V rail. In addition, the ...

Page 18

UTPUT NABLE The LX1671 MOSFET driver outputs are shut off by pulling the soft-start pin below 0.3V. The LDO voltage regulator has its own Enable/Disable pin (LDDIS) for control of this output voltage ...

Page 19

The power N-MOSFET transistor’s total gate charge spec, (Qg) ...

Page 20

TM PW 38-Pin Thin Small Shrink Outline (TSSOP 38-Pin Plastic MLPQ (5x7mm EP Note: Dimensions do not include mold flash or protrusions; these shall not exceed 0.155mm(0.006”) on any side. Lead dimension ...

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TM PRODUCTION DATA – Information contained in this document is proprietary to Microsemi and is current as of publication date. This document may not be modified in any way without the express written consent of Microsemi. Product processing does not ...

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