LX1676

Microsemi

Integrated Products Division

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

Page 1

Mobile AMD Athlon

™ VRM Controller

Copyright

© 2000

Revision: 1.0, 4/12/2005

TM

®

DESCRI PTI O N

The LX1676 is a highly integrated

VRM power supply controller IC

featuring

two

PWM

switching

regulator stages.

The

two

constant

frequency

voltage-mode

PWM

phases

are

configured as a single biphase high

current output core supply.

In biphase operation, the high

current (>25A) output is generated by

balances the currents in the two

phases. Power loss and noise, due to

the ESR of the input capacitors, are

minimized by operating the PWMs

180° out of phase.

A

synchronized

Transient

Correction Loop† provides except-

ional control of the output droop and

overshoot during very high di/dt load

changes, the circuit can be configured

for droop only, overshoot only or

both.

This architecture also minimizes

capacitor

requirements

while

maximizing regulator response.

A true differential input amplifier is

used for remote voltage sensing at the

processor core.

A VID code generator provides an

internal reference that will set the

output voltage. This VID code can be

changed during operation and the

reference will slew the output voltage to

its new setting at a preset rate. During

VID changes on the fly the Power Good

indication will stay valid.

Current through the lower phase 1

MOSFET will be sampled using its

down.

For further protection, an over

voltage circuit will trip at a specified

setting and clamp the output by turning

off the upper MOSFETs and turning on

the lower MOSFETs.

The upper MOSFET drivers will use

a bootstrap capacitor to provide the

upper drive voltage over the input

voltage range of 6 to 24 volts.

IMPORTANT:

† Patent numbers US6292378,US6285571,US6356063, US6605931

KEY FEATUR ES

High Current Biphase

Operation

Outputs As Low As 0.925V

† Biphase LoadSHARE

TM

† Transient Correction Loop

Reduces Required

Capacitance

Differential Amplifier For

Remote Voltage Sensing

Integrated High Current

MOSFET Drivers

200KHz to 1MHz Frequency

Operation

Programmable Slew Rate

Control For Start-Up Sequence

and VID change

VID Changes On The Fly

Power Good Indicator

Short Circuit Protection

Output Over Voltage and

Under Voltage Protection

No current-sense resistors

APPLI C ATION S

AMD Mobile Athlon

™ or

Duron

™ Processor Core

Voltage Supply

Voltage Regulator Modules

PRODUCT H I GHLIGHT

L X 16 76

5 B i t V I D

70n H

Tr a n s i e n t C o r r e c t i on Loop

Vi n 6 t o 2 4 V

Vi n 6 t o 2 4 V

V out

Vi n + 5 V

PACKAGE ORDER I N FO

PW

Plastic TSSOP

38-Pin

LQ

Plastic MLPQ

38-Pin

°C)

RoHS Compliant / Pb-free Transition DC: 0518

RoHS Compliant / Pb-free Transition DC: 0512

0 to 70

LX1676CPW

LX1676CLQ

Note: Available in Tape & Reel. Append the letters “TR” to the part number. (i.e. LX1676CLQ-TR)