PRODUCT HIGHLIGHT
DUAL OUTPUT PWM CONTROLLERS WITH 5-BIT DAC
P RODUCTION DATA SHEET
T HE I NFINITE P OWER OF I NNOVATION
LX1664/64A, LX1665/65A
PACKAGE ORDER INFORMATION
T
A
(°C)
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
1
20A
L
2
1µH
LX1665 IN A PENTIUM II SINGLE-CHIP POWER SUPPLY SOLUTION
Copyright © 1999
Rev. 1.2 11/99
1
11861 WESTERN AVENUE, GARDEN GROVE, CA. 92841, 714-898-8121, FAX: 714-893-2570
L INF INITY MICROELECTRONICS INC.
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
■ 5-bit Programmable Output For CPU Core
Supply
■ Adjustable Linear Regulator Driver Output
■ No Sense Resistor Required For Short-
Circuit Current Limiting
■ Designed To Drive Either Synchronous Or
Non-Synchronous Output Stages
■ Soft-Start Capability
■ Modulated, Constant Off-Time Architecture
For Fast Transient Response And Simple
System Design
■ 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
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
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
■ Socket 7 (Pentium Class) Microprocessor
Supplies (including Intel Pentium Processor,
AMD-K6
TM
And Cyrix
®
6x86
TM
, Gx86
TM
and
M2
TM
Processors)
■ Pentium II and Deschutes Processor & L2-
Cache Supplies
■ Voltage Regulator Modules
IMPORTANT: For the most current data, consult LinFinity's web site: http://www.linfinity.com.
See next page
for
Selection Guide
