LX1668CDW Microsemi Analog Mixed Signal Group, LX1668CDW Datasheet
LX1668CDW
Manufacturer Part Number
LX1668CDW
Description
IC CTRLR DC/DC PROG SW 20SOIC
Manufacturer
Microsemi Analog Mixed Signal Group
Datasheet
1.LX1668CDW.pdf
(15 pages)
Specifications of LX1668CDW
Applications
Controller, Intel Pentium® II, III
Voltage - Input
5V, 12V
Number Of Outputs
3
Voltage - Output
1.3 ~ 3.5 V
Operating Temperature
0°C ~ 70°C
Mounting Type
Surface Mount
Package / Case
20-SOIC
Lead Free Status / RoHS Status
Lead free / RoHS Compliant
Available stocks
Company
Part Number
Manufacturer
Quantity
Price
Part Number:
LX1668CDW
Manufacturer:
LINFINITY
Quantity:
20 000
T
Copyright © 1999
Rev. 1.0a,2005-03-01
The LX1668 is a Monolithic Switching
Regulator Controller IC designed to
provide a low cost, high performance
adjustable power
microprocessors
requiring a very fast transient response and a
high degree of accuracy. It provides a
programmable switching regulator output,
together with one internal linear low dropout
regulator and one adjustable linear regulator
driver. The LX1668 offers a triple-output
single-chip power supply for Pentium® II
and other processors.
Programmable
Driver for CPU Core. The main output is
adjustable from 1.3 to 3.5V using a
TTLcompatible 5-bit digital code to meet
Intel specifications. The IC can read the
signal from a DIP-switch, hardwired to
Pentium II processor’s pins or from software.
The 5-bit code adjusts the output voltage
between
increments, and between 2.0 and 3.5V in
100mV increments. The device can drive
dual
efficiencies of 85 – 90%, even with loads in
excess of 10A.
H E
IMPORTANT: For the most current data, consult MICROSEMI’s website: http://www.microsemi.com
I
N F I N I T E
MOSFET’s
1.30
and
and
Synchronous
P
supply for
resulting
O W E R
2.05V
other
11861 W
Note: Available in Tape & Reel. Append the letters “TR” to the part number. (i.e. LX1668CDW-TR)
T
3.3V
0 to 70
V
2.5V
V
1.5V
OUT2
OUT3
A
(°C)
22µF
C5
O F
330µF
applications
ESTERN
1µF
in
C8
in
C4
D E S C R I P T I O N
C6
330µF
L
advanced
Rectifier
I
5V
I N
DW
typical
50mV
N N O V A T I O N
C9
1µF
A
1µF
R1, 0
R2, 50k
C3
F
VENUE
Q3
IRLZ44
I N I T Y
12V
RoHS Compliant / Pb-free
Plastic SOWB
20-Pin
, G
Transition DC: 0516
Internal Low Dropout [LDO] Regulator
provides a fixed 2.5V output for powering
the clock circuit at up to 250mA.
External Linear Regulator Driver output
can be connected to a MOSFET to provide a
high-current
suitable for supplying the GTL+ bus
circuitry
motherboard at 1.5V.
Short-circuit Current Limiting without
Expensive Current Sense Resistors. The
current sensing mechanism can use a PCB
trace resistance or the parasitic resistance of
the main inductor. For applications requiring
a high degree of accuracy, a conventional
sense resistor can be used.
Ultra-Fast Transient Response Reduces
System
modulated off-time architecture results in
the fastest transient response for a given
inductor.
Small Package Size. The LX1668 is
available in an economical 20-pin wide
body SOIC or a space-saving 20-pin TSSOP
package.
P R O D U C T H I G H L I G H T
LX1668CDW
C7
1µF
ARDEN
10
PACKAGE ORDER INFO
1
2
3
4
5
6
7
8
9
M
TDRV
V
V
V
V
L
L
VID0
VID1
VID2
DRV
FB
CC12
CC5
OUT2
CC3
I C R O E L E C T R O N I C S
G
ROVE
LX1668
Cost.
on
PWRGD
, CA. 92841, 714-898-8121, F
1µH
AGND
SS/EN
L2
PGND
BDRV
V
VID4
VID3
OVP
adjustable
CORE
V
a
FB
20
19
18
17
16
15
14
13
12
11
P
C
The
SS
ROGRAMMABLE
Pentium
IRL3102
0.1µF
Q1
PWRGD
VID4
VID3
VID2
VID1
VID0
P
fixed
PW
R O D U C T I O N
Q2
IRL3303
LDO
2.5µH
L1
C2
1500µFx3
II
RoHS Compliant / Pb-free
2.5mΩ
R
SENSE
frequency
processor
Plastic TSSOP
20-Pin
M
Transition DC: 0442
3.3V / 5V
I
function
LX1668CPW
N C
AX
ULTIPLE
R3
10k
2N6504
: 714-893-2570
Q4*
.
SCR
*
OVP crowbar
Q4 optional
O
CPU Core
C1
1500µF x 6
V
UTPUT
CORE
D
A T A
5-Bit Programmable Output For
CPU Core Supply
Internal Fixed 2.5V Low Dropout
Regulator
Adjustable Linear Regulator
Driver
Complete Single-Chip Power
Solution For Pentium II
Processors
No Sense Resistor Required For
Short-Circuit Current Limiting
Soft-Start And Hiccup-Mode
Current Limiting Functions
Modulated Constant Off-Time
Control Mechanism For Fast
Transient Response And Simple
System Design
Power Good Flag
Over-Voltage Pin & SCR
Digital-Compatible Inputs
(Including VID Pins)
Output Disable Function Shuts
Off PWM While Keeping 2.5V
LDO Active - Compatible With
"Green PC" And "Instant On"
Requirements
Compatible to VRM8.2 - 8.4
Specifications
Pentium II & Pentium III
Processor Supplies
Voltage Regulator Modules
General Purpose And
Microprocessor DC:DC Supplies
DC : DC C
K E Y F E A T U R E S
K E Y F E A T U R E S
S
H E E T
ONTROLLER
LX1668
1
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LX1668CDW Summary of contents
Page 1
... C4 330µF V OUT3 1.5V C6 330µF T (° Note: Available in Tape & Reel. Append the letters “TR” to the part number. (i.e. LX1668CDW-TR) L Copyright © 1999 Rev. 1.0a,2005-03-01 11861 W ESTERN P ROGRAMMABLE Internal Low Dropout [LDO] Regulator provides a fixed 2.5V output for powering the clock circuit 250mA ...
Page 2
LX1668 P ROGRAMMABLE LUT E MAXIM UM RAT INGS 12V Supply Voltage (V ...
Page 3
ROGRAMMABLE (Unless otherwise specified, 4.75V < V < 5.25V and 10.8V < V CC5 T ...
Page 4
LX1668 P ROGRAMMABLE Table 1 - Adaptive Transient Voltage Output VID4 ...
Page 5
ROGRAMMABLE 100 EFFICIENCY AT 3.1V EFFICIENCY AT 2.8V 75 EFFICIENCY AT ...
Page 6
LX1668 P ROGRAMMABLE Pin Pin Number Designator Description 1 TDRV Gate drive to the top FET. ...
Page 7
ROGRAMMABLE SWITCHER OUTPUT VOLTAGE REGULATION Refer to the IC Block Diagram and the Product Highlight ...
Page 8
LX1668 P ROGRAMMABLE OVER-CURRENT PROTECTION (OCP) and HICCUP The over-current protection function is tripped when the ...
Page 9
ROGRAMMABLE Ref Description U1 Controller IC C1 Capacitor, 1500µF, 6.3V, 44m ESR C2 Capacitor, 1500µF, ...
Page 10
LX1668 P ROGRAMMABLE L = 5µH, L OUT OUTPUT INDUCTOR The output inductor should be selected ...
Page 11
ROGRAMMABLE OUTPUT CAPACITOR (continued) excursion in the transient. Adaptive voltage positioning in- creases the value ...
Page 12
LX1668 P ROGRAMMABLE CURRENT LIMIT (continued) There are several alternative types of sense resistor. The surface-mount ...
Page 13
ROGRAMMABLE CURRENT LIMIT (continued) General Guidelines for Selecting trip Select ...
Page 14
LX1668 P ROGRAMMABLE LINEAR REGULATOR Capcitor Selection The internal LDO regulator and the external linear regulator ...
Page 15
ROGRAMMABLE LINEAR REGULATOR (continued) 3.3V/5V LX1668 6 L DRV 10k 10k ...