LX1664/64A, LX1665/65A
DUAL OUTPUT PWM CONTROLLERS WITH 5-BIT DAC
T H E I N F I N I T E P O W E R O F I N N O V A T I O N
P R O D U C T I O N D A T A S H E E T
DESCRIPTION
KEY FEATURES
I 5-bit Programmable Output For CPU Core
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.
set by a DIP switch on the motherboard, or
hardwired into the processor’s package (as
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)
in the case of Pentium® Pro and Pentium II
processors). The 5-bit code adjusts the
output voltage between 1.30 and 2.05V in
50mVincrementsandbetween2.0and3.5V
in 100mV increments, conforming to the
Intel Corporation specification. The device
candrivedualMOSFET’sresultingintypical
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.
APPLICATIONS
I Socket 7 (Pentium Class) Microprocessor
Supplies (including Intel Pentium Processor,
AMD-K6TM And Cyrix® 6x86TM, Gx86TM and
M2TM Processors)
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 Pentium II and Deschutes Processor & L2-
(continued next page)
Cache Supplies
I Voltage Regulator Modules
IMPORTANT: For the most current data, consult LinFinity's web site: http://www.linfinity.com.
PRODUCT HIGHLIGHT
LX1665 IN A PENTIUM II SINGLE-CHIP POWER SUPPLY SOLUTION
F1 20A
12V
5V
L2
1µH
C3
0.1µF
6.3V
C5
1µF
U1
LX1665
1500µF x3
C2
Q1
IRL3102
1
2
3
4
5
6
7
8
9
18
R1
0.0025
SS
VC1
TDRV
GND
BDRV
VCC
Supply Voltage
for CPU Core
17
16
15
14
13
12
11
10
L1
INV
VOUT
VCC_CORE
VID0
VID1
VID2
VID3
VID4
LFB
2.5µH
Q2
IRL3303
C1
VID0
VID1
VID2
VID3
VID4
6.3V, 1500µF x 3**
** Three capacitors for Pentium
Four capacitors for Pentium II
C9
330µF
CT
C8
680pF
OV
Q4
Supply Voltage
For I/O Chipset or GTL+ Bus
LDRV
IRLZ44
PWRGD
R5
C7
330µF
18-pin
Wide-Body SOIC
OV
PWRGD
R6
PACKAGE ORDER INFORMATION
Plastic DIP
16-pin
Plastic DIP
18-pin
Plastic SOIC
16-pin
Plastic SOIC Wide
18-pin
TA (°C)
0 to 70
N
N
D
DW
LX1664CN
LX1665CN
LX1664CD
LX1665CDW
LX1664ACN
LX1665ACN
LX1664ACD
LX1665ACDW
Note: All surface-mount packages are available in Tape & Reel. Append the letter "T" to part number. (e.g. LX1664CDT)
L I N F I N I T Y M I C R O E L E C T R O N I C S I N C .
11861 WESTERN AVENUE, GARDEN GROVE, CA. 92841, 714-898-8121, FAX: 714-893-2570
Copyright © 1999
Rev. 1.2 11/99
1