L I N D
O C
# :
1662
LX1662/62A, LX1663/63A
S
INGLE
-C
HIP
P
ROGRAMMABLE
PWM C
ONTROLLERS WITH
5-B
IT
DAC
T
H E
I
N F I N I T E
P
O W E R
O F
I
N N O VA T I O N
P
R O D U C T I O N
D
A T A
S
H E E T
DESCRIPTION
The LX1662/62A and LX1663/63A are
Monolithic Switching Regulator Con-
troller IC鈥檚
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
LX1662A
and
LX1663A
have reduced current sense com-
parator threshold for optimum perfor-
mance using a PCB trace. For applications
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
set by a DIP switch on the motherboard, or
hardwired into the processor鈥檚 package (as
in the case of Pentium
庐
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鈥檚 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).
Smallest Package Size.
The LX1662 is
available in a narrow body 14-pin surface
mount IC package for space sensitive appli-
cations. The LX1663 provides the additional
functions of Over Voltage Protection (OVP)
and Power Good (PWRGD) output drives
for applications requiring output voltage
monitoring and protection functions.
Ultra-Fast Transient Response Re-
duces System Cost.
The modulated off-
time architecture results in the fastest tran-
sient response for a given inductor, reduc-
ing output capacitor requirements, and re-
ducing the total regulator system cost.
Over-Voltage Protection and Power
Good Flag.
The OVP output in the LX1663
& LX1663A can be used to drive an SCR
crowbar circuit to protect the load in the
event of a short-circuit of the main MOSFET.
The LX1663 & LX1663A also have a logic-
level Power Good Flag to signal when the
output voltage is out of specified limits.
K E Y F E AT U R E S
I
5-bit Programmable Output For CPU Core
Supply
I
No Sense Resistor Required For Short-
Circuit Current Limiting
I
Designed To Drive Either Synchronous Or
Non-Synchronous Output Stages
I
Lowest System Cost Possible For Price-
Sensitive Pentium And Pentium II Class
Applications
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
(LX1663 only)
I
Small, Surface-Mount Packages
A P P L I C AT I O N S
I
Socket 7 Microprocessor Supplies
(including Intel Pentium Processor, AMD-
K6
TM
And Cyrix
庐
6x86
TM
, Gx86
TM
and M2
TM
Processors)
I
Pentium II and Deschutes Processor & L2-
Cache Supplies
I
Voltage Regulator Modules
I
General Purpose DC:DC Converter
Applications
IMPORTANT:
For the most current data, consult LinFinity's web site:
http://www.linfinity.com.
PRODUCT HIGHLIGHT
LX1662
IN A
P
ENTIUM
/P
ENTIUM
II
S
INGLE
-C
HIP
P
OWER
S
UPPLY
S
OLUTION
C
3
0.1碌F
12V
L
2
1碌H
5V
6.3V
1500碌F x3
C
2
U1
LX1662
1
2
3
C
5
1碌F
V
C1
TDRV
GND
BDRV
V
CC
C
T
VID4
14
13
12
11
10
9
8
SS
INV
V
CC_CORE
VID0
VID1
VID2
VID3
Q
1
IRL3102
L
1
, 2.5碌H
Q
2
IRL3303
R
1
2.5m9
Supply Voltage
for CPU Core
VID0
VID1
VID2
VID3
VID4
4
5
6
7
V
OUT
C
8
680pF
6.3V, 1500碌F x 3**
** Three capacitors for Pentium
Four capacitors for Pentium II
C
1
14-pin, Narrow Body SOIC
T
A
(掳C)
0 to 70
N
Plastic DIP
14-pin
LX1662CN
LX1662ACN
N
Plastic DIP
16-pin
LX1663CN
LX1663ACN
D
Plastic SOIC
14-pin
LX1662CD
LX1662ACD
D
Plastic SOIC
16-pin
LX1663CD
LX1663ACD
Note: All surface-mount packages are available in Tape & Reel. Append the letter "T" to part number. (i.e. LX1662CDT)
Copyright 漏 1999
Rev. 1.1 11/99
L
IN
F
INITY
M
ICROELECTRONICS
I
NC
.
11861 W
ESTERN
A
VENUE
, G
ARDEN
G
ROVE
, CA. 92841, 714-898-8121, F
AX
: 714-893-2570
Selection Guide
PA C K A G E O R D E R I N F O R M AT I O N
See next page
for
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