PRODUCT H IGHLIGHT

OF

LX1664/64A, LX1665/65A

P ACKAGE ORDER INFORMATION

T

Plastic DIP

16-pin

0 to 70

LX1664CN

LX1665CN

LX1664CD

LX1665CDW

LX1664ACN

LX1665ACN

LX1664ACD

LX1665ACDW

N

Note: All surface-mount packages are available in Tape & Reel. Append the letter "T" to part number. (e.g. LX1664CDT)

Plastic DIP

18-pin

N

Plastic SOIC

16-pin

D

Plastic SOIC Wide

18-pin

DW

SS

TDRV

V

CC

INV

V

CC_CORE

VID0

VID1

VID2

VID3

OV

C

T

BDRV

GND

V

C1

U1

LX1665

VID3

C

5

1µF

12V

R

1

V

OUT

5V

18-pin

Wide-Body SOIC

Q

1

IRL3102

2.5µH

6.3V, 1500µF x 3**

14

13

12

11

10

1

2

3

4

5

6

7

C

8

680pF

VID2

VID1

VID0

VID4

C

3

0.1µF

0.0025

Supply Voltage

for CPU Core

6.3V

1500µF x3

** Three capacitors for Pentium

Four capacitors for Pentium II

VID4

L

DRV

Supply Voltage

For I/O Chipset or GTL+ Bus

8

16

15

L

FB

PWRGD

9

PWRGD

OV

17

18

Q

2

IRL3303

Q

4

IRLZ44

C

7

330µF

R

5

R

6

L

1

C

2

C

1

C

9

330µF

F

L

2

1µH

Copyright © 1999

Rev. 1.2 11/99

1

DESCRIPTION

KEY FEATURES

The LX1664/64A and LX1665/65A are

monolithic switching regulator con-

troller IC’s designed to provide a low cost,

high performance adjustable power supply

for advanced microprocessors and other

applications requiring a very fast transient

response and a high degree of accuracy.

Short-circuit Current Limiting with-

out Expensive Current Sense Resistors.

Current-sensing mechanism can use PCB

trace resistance or the parasitic resistance of

the main inductor. The

LX1664A and

LX1665A have reduced current sense com-

parator threshold for optimum perfor-

mance using a sense resistor. For applica-

tions requiring a high degree of accuracy, a

conventional sense resistor can be used to

sense current.

Programmable Synchronous Recti-

fier Driver for CPU Core.

The main

output is adjustable from 1.3V to 3.5V using

a 5-bit code. The IC can read a VID signal

I 5-bit Programmable Output For CPU Core

Supply

I Adjustable Linear Regulator Driver Output

I No Sense Resistor Required For Short-

Circuit Current Limiting

I Designed To Drive Either Synchronous Or

Non-Synchronous Output Stages

I Soft-Start Capability

I Modulated, Constant Off-Time Architecture

For Fast Transient Response And Simple

System Design

I Available Over-Voltage Protection (OVP)

Crowbar Driver And Power Good Flag

(LX1665 only)

set by a DIP switch on the motherboard, or

hardwired into the processor’s package (as

processors). The 5-bit code adjusts the

output voltage between 1.30 and 2.05V in

50mV increments and between 2.0 and 3.5V

in 100mV increments, conforming to the

Intel Corporation specification. The device

can drive dual MOSFET’s resulting in typical

efficiencies of 85 - 90% even with loads in

excess of 10 amperes. For cost sensitive

applications, the bottom MOSFET can be

replaced with a Schottky diode (non-syn-

chronous operation).

Linear Regulator Driver. The LX1664/

65 family of devices have a secondary

regulator output. This can drive a MOSFET

or bipolar transistor as a pass element to

construct a low-cost adjustable linear regu-

lator suitable for powering a 1.5V GTL+ bus

or 2.5V clock supply.

(continued next page)

APPLICATIONS

I Socket 7 (Pentium Class) Microprocessor

Supplies (including Intel Pentium Processor,

I Pentium II and Deschutes Processor & L2-

Cache Supplies

I Voltage Regulator Modules

IMPORTANT: For the most current data, consult LinFinity's web site: http://www.linfinity.com.